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Decision support system for construction cycle design Law, Gordon Ki-Wai 1987-12-31

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DECISION  SUPPORT  SYSTEM  FOR CONSTRUCTION  CYCLE  DESIGN  by  GORDON KI-WAI LAW  THESIS SUBMITTED IN PARTIAL FULFILLMENT THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE  in THE FACULTY OF GRADUATE STUDIES DEPARTMENT OF CIVIL  ENGINEERING  We accept t h i s t h e s i s as conforming to the r e q u i r e d  standard.  THE UNIVERSITY OF BRITISH COLUMBIA APRIL 1987  © Gordon Ki-Wai Law, 1987.  In  presenting  requirements British freely that  this f o r an  Columbia, available  or  understood  that  financial  advanced  I  agree  gain  degree  that  f o r extensive  purposes  Department  in partial  f o r reference  permission  scholarly  thesis  by  copying granted  his  or  her  not  be  allowed  permission.  DEPARTMENT OF C I V I L  ENGINEERING  The U n i v e r s i t y o f B r i t i s h 2075 Wesbrook P l a c e Vancouver, Canada V6T 1W5  Date:  APRIL 1987  Columbia  of by  shall I  this the  of  this  without  the of  make i t  further  agree  thesis f o r Head  representatives.  or publication  of  the University  and s t u d y .  be  shall  at  the Library  may  copying  fulfillment  of  my  It  i s  thesis f o r my  written  ii  ABSTRACT  The design  o b j e c t i v e of t h i s t h e s i s i s to develop a  of a computerized  construction  conceptual  environment f o r d e t a i l e d design of  activities  associated  with  projects  c h a r a c t e r i z e d by s i g n i f i c a n t r e p e t i t i o n . High-rise of  r e p e t i t i v e construction  design  of a t y p i c a l  understanding the  building construction  activity  floor  p r o j e c t s . The c o n s t r u c t i o n structure  of the d i f f i c u l t y design  i s used as the example  process.  i s studied  and complexity  Modeling  cycle  to gain  an  involved i n  technigues  currently  used i n c o n s t r u c t i o n p l a n n i n g ,  modeling technigues developed  in  research,  the f i e l d  balancing reviewed  of  operations  technigues to  construction  used  determine cycle  in  and  industrial  their  assembly  line  engineering  are  applicability  for detailed  design. o  Using the concept of d e c i s i o n support systems developed in  the  fields  engineering  for  of  management  solving  problems, a conceptual  science  ill-structured  design  f o r c o n s t r u c t i o n c y c l e design  and and  of a d e c i s i o n i s developed.  knowledge ill-defined  support  system  iii T A B L E OF CONTENTS  ABSTRACT  i i  LIST OF FIGURES  ix  ACKNOWLEDGEMENT  xi  1.  INTRODUCTION  1  1.1  2  1.2 1.3 1.4 2.  T r a d i t i o n a l Approach t o C o n s t r u c t i o n P l a n n i n g . R e p e t i t i v e C o n s t r u c t i o n and Construction Planning Need f o r A c t i v i t y Design F i e l d Management  Tools f o r 4  Research O b j e c t i v e and Approach  5  TERMINOLOGY  7  2.1  H i e r a r c h i c a l L e v e l s i n C o n s t r u c t i o n Management  8  2.2  Terminology f o r Information 2.2.1 2.2.2  3.  3  CYCLE PLANNING  Representation  ... 10  Work Breakdown S t r u c t u r e i n "Assemblies"  11  Work Breakdown S t r u c t u r e i n Work/Component " C a t e g o r i e s "  12  IN REPETITIVE  CONSTRUCTION  PROJECTS  14  3.1  The T y p i c a l C o n s t r u c t i o n C y c l e  15  3.2  The C o n s t r u c t i o n C y c l e P l a n n i n g Problem  16  3.2.1 3.2.2  Design Parameters and Decision Variables Need f o r An A c t i v i t y Design Environment  17 24  iv 4.  E X I S T I N G  4.1  MODELS  FOR  C O N S T R D C T I O N  P L A N N I N G  26  D e t e r m i n i s t i c Models  26  4.1.1  Bar Charts  26  4.1.2  C r i t i c a l Path Method  4.1.3  Line-of-Balance  4.1.4  Time Space Scheduling  4.1.5  M u l t i p l e A c t i v i t y and  (CPM)  29  (LOB)  31 Method  (TSM).  Crew Balance Charts 4.2  P r o b a b i l i s t i c Models 4.2.1  37 39  U n c e r t a i n t i e s i n The C o n s t r u c t i o n Environment  39  4.2.2  Queuing Models  40  4.2.3  D i s c r e t e Event S i m u l a t i o n  42  4.2.4  Monte C a r l o S i m u l a t i o n  44  4.2.5  Program E v a l u a t i o n and Review Technique  (PERT)  45  4.2.6  D e c i s i o n CPM  4.2.7  G r a p h i c a l E v a l u a t i o n and Review Technique (GERT) P r o j e c t Length A n a l y s i s and E v a l u a t i o n Technique (PLANET) ... P r o b a b i l i s t i c Networking E v a l u a t i o n  4.2.8 4.2.9  Technique  5.0  34  46  (PNET)  4.3  Mathematical Programming  4.4  Current  P R O D U C T I O N B A L A N C I N G  AND  Techniques  A S S E M B L Y  Production  5.2  Assembly Line 5.2.1 LineP r oB da ul ca tn ic oi nn g  49 50  L I N E  (ALB)  5.1  47 48  P r a c t i c e i n C o n s t r u c t i o n Modeling .... P L A N N I N G  46  55  Planning  56 Procedure  57 58  V  5.2.2 5.3  Example of L i n e B a l a n c i n g  Assembly L i n e B a l a n c i n g  59  Algorithms  5.3.1  System C o n s t r a i n t s  5.3.2  P r i o r i t i e s of Work Element  63 64  Assignment 5.3.3  Balanced Assignment and Smoothing .  65  5.3.4  V a r i a b l e Element Time  66  5.3.5  Element S h a r i n g , and  5.4  5.5  64  M u l t i p l e Manning  Multiple Stations  66  5.3.6  Related A c t i v i t i e s  67  5.3.7  Other C o n s i d e r a t i o n s  68  Assembly L i n e B a l a n c i n g and C o n s t r u c t i o n C y c l e Design 5.4.1 S i m i l a r i t i e s Between ALB and C o n s t r u c t i o n C y c l e Design 5.4.2 D i f f e r e n c e s Between ALB and C o n s t r u c t i o n C y c l e Design  69 69 70  A p p l i c a t i o n of ALB to C o n s t r u c t i o n C y c l e Design  6.  73  5.5.1  L i m i t a t i o n s of ALB Algorithms  74  5.5.2  A p p l i c a t i o n of ALB P r i n c i p l e s to C o n s t r u c t i o n C y c l e Design  76  DECISION SUPPORT SYSTEM  (DSS) FOR  ACTIVITY DESIGN  78  6.0  Objectives  6.1  The C r e a t i v e Human D e c i s i o n Making Process  ...  80  6.2  D e c i s i o n Support Systems f o r D e c i s i o n Making .  82  6.3  D e c i s i o n Support System Activity  78  (DSS) f o r  Design  83  6.3.1  Module 1 - Problem R e c o g n i t i o n  6.3.1.1  Representation Information  ....  89  of P r o j e c t 89  vi 6.3.2  Module 2 - Problem D e f i n i t i o n  6.3.2.1  Current P r a c t i c e and  91  Problem D e f i n i t i o n  91  6.3.2.2  Problem D e f i n i t i o n and The DSS ....  6.3.2.3  Problem D e f i n i t i o n and Computer Input Format  93  6.3.3  Module 3 - S o l u t i o n Formulation  6.3.3.1  Review and S e l e c t C o n s t r u c t i o n Technologies Current P r a c t i c e and S e l e c t i o n of Technologies S e l e c t i o n of Technologies and The DSS  6.3.3.1.1 6.3.3.1.2 6.3.3.1.3  92  ...  95 97 98 98  A t t r i b u t e s of C o n s t r u c t i o n Technologies  100  6.3.3.2  Define C o n s t r u c t i o n Operations  6.3.3.2.1  D e f i n i n g an Operation  105  6.3.3.2.2  D e f i n i n g Related Operations  105  6.3.3.2.3  R e d e f i n i n g Operations  107  6.3.3.3  Sequence Defined Operations  110  6.3.3.3.1  Operations Sequence and The P-Matrix Operations Sequence and Lag C a l c u l a t i o n s  6.3.3.3.2 6.3.3.3.3 6.3.3.3.4  R e p e t i t i v e C o n s t r u c t i o n and The P-Matrix Sequencing The  Operations  .... 104  110 112 112  with  P-Matrix  114  6.3.3.4  Estimate and Assign Resources  115  6.3.3.4.1  Current P r a c t i c e and Resource Assignment ALB and E s t i m a t i o n of Resource Requirements  116  6.3.3.4.2  118  vi i 6.3.3.4.3  Assigning  Labour Crews  121  6.3.3.4.4  Assigning  S p e c i a l Resources  123  6.3.4  Module 4 - S o l u t i o n A n a l y s i s  126  6.3.4.1  Current P r a c t i c e i n Resource A n a l y s i s and C y c l e Design  126  6.3.4.2  C r i t i c a l Path Method f o r Solution Analysis  6.3.4.3  Presentation  6.3.4.3.1  C r i t i c a l Path A n a l y s i s R e s u l t s  6.3.4.3.2  Status  6.3.4.3.3  Work Schedules f o r Labour Crews and S p e c i a l Resources Module 5 - Design Improvement and Enrichment  6.3.5 6.3.5.1 6.3.5.2 6.3.5.3 6.3.5.4  7.  128  CONCLUSIONS  of A n a l y s i s R e s u l t s  .. 129  .... 129  of Committed Resources  130 131 138  D i f f i c u l t i e s i n Improving An A c t i v i t y Design  138  An Approach to S o l u t i o n Improvement  139  S o l u t i o n Improvement and The M u l t i p l e Operation Time Chart  ... 142  I n s t r u c t i o n s to Manipulate The M u l t i p l e Operation Time Chart  ... 143  AND RECOMMENDATIONS  146  7.1  Conclusions  146  7.2  Recommendations f o r Future Research  148  7.2.1 7.2.2 7.2.3 7.2.4  Computer Programming and Field Application  148  Graphics I n t e r f a c e f o r C y c l e Design  148  I n t e g r a t i o n with Other Management Functions  149  I n t e g r a t i o n with Other Modeling Technigues  150  viii 7.2.5  BIBLIOGRAPHY  D e t a i l e d Planning of C o n s t r u c t i o n C y c l e Operations  151 152  ix  LIST OF  FIGURES  4.1  Fenced bar chart of a warehouse p r o j e c t  28  4.2  Precedence diagram of a warehouse p r o j e c t  28  4.3  Line-of-Balance  33  4.4  Time Space diagrams  36  4.5  Multiple activity  38  4.6  Current a p p l i c a t i o n of CPM construction planning  5.1 5.2  modeling technique  chart of a b u i l d i n g c y c l e in  54  Example of a 20-element assembly p r o d u c t i o n process Suggested balance  60  to the assembly  p r o d u c t i o n process  62  6.1  C r e a t i v e human d e c i s i o n making process  81  6.2  Problem r e c o g n i t i o n , problem d e f i n i t i o n and solution formulation S o l u t i o n a n a l y s i s and design improvement and  87  6.3  enrichment  88  6.4  Problem d e f i n i t i o n  94  6.5  Review and  99  6.6  Review work tasks of c o n s t r u c t i o n technology  103  6.7  D e f i n i n g an o p e r a t i o n  108  6.8  Defining related operations  109  6.9  Sequencing o p e r a t i o n s - the P-Matrix  111  6.10  Estimate  120  6.11  A s s i g n i n g labour crews to o p e r a t i o n s  124  6.12  Assigning special  125  6.13 6.14  C r i t i c a l path a n a l y s i s r e s u l t s Resource Status Table  select construction technologies  and  commit resource pools  resources  to o p e r a t i o n s  134 135  X 6.15  S e l e c t crews and s p e c i a l resources  6.16  i n M.O.T. chart M u l t i p l e Operation Time  6.17  General Rules f o r design  to report  (M.O.T.) chart improvement  136 137 141  xi  ACKNOWLEDGEMENTS  I want Russell, and  to express  my  my  supervisor,  encouragement  sincere  gratitude  f o r h i s valuable  throughout  my  advice,  studies.  a p p r e c i a t e h i s e f f o r t s and time i n reviewing the  valuable  suggestions  t o improve  i s most  I  the content.  gratefully  guidance greatly  t h i s t h e s i s and  are extended to Dr. W.F. C a s e l t o n f o r reviewing Acknowledgement  to Dr. A. D.  My  this  extended  thanks thesis. t o the  Canada Mortgage and Housing C o r p o r a t i o n who has provided the scholarship  which  enabled  the U n i v e r s i t y of B r i t i s h A  special  colleagues  who  t r e a s u r e d support  thank have  me to pursue  graduate  s t u d i e s at  Columbia. you  given  to me  professors, valuable  friends  advice  and encouragement during t h i s  and  study.  and much  1  1.  Construction  INTRODUCTION  projects  are t r a d i t i o n a l l y  owners or users who are concerned aesthetical the  aspects  difficulties  of the f a c i l i t i e s  i n producing  construction  industry  technologies  that  construction  duration  and l i t t l e  through  mass  firms and s u b c o n t r a c t o r s  associated  with  their  costs to an extent in t h e i r  and  has  and  threaten  time,  The  methods and and s a f e l y  relatively  general  contracting  their a c t i v i t i e s and  s p e c i a l i z a t i o n and  to  reduce  when problems  overall develop  through  activities  except when a c o n s t r u c t i o n a c t i v i t y on  unit  Expertise  by l e a r n i n g  of c o n s t r u c t i o n  within  technologies  i n business.  i s developed  impact  short  f o r economies of s c a l e  to master the s k i l l s  analysis  significant  completion  of  Therefore,  that they can stay  in-depth  r a r e l y considered  are  concentrate  s p e c i a l i z e d areas  practice;  end products.  economically  i s offered  production.  consider  facilities.  projects  scope  l i m i t e d areas i n order  and r a r e l y  the d e s i r e d  can e f f i c i e n t l y ,  by  the f u n c t i o n a l and  must develop c o n s t r u c t i o n  produce the d e s i r e d p h y s i c a l Most  about  developed  project  during  is  i s new  cost  and  construction  completion of the p r o j e c t , or when the a c t i v i t y  i s to be repeated a s i g n i f i c a n t than twelve to f i f t e e n  times).  number of times  (say g r e a t e r  2  1.1  TRADITIONAL  Current as  on  requirements  of  and  projects.  with  c y c l e schedule,  to  plan,  to achieve  them.  methods of accomplishment higher  management,  production  level  immediate  concerns  method  and  elimination interested  of  of  imbalances  affecting  valuable  a  analysis  with  which  of  mean  adoption  as  to meet  construction idle  are  detailed  not short  are concerned with the goals  imposed by  efforts  commitment  and  management  they  a  their  of  at  process.  of  the Their  resources,  operations  the  and  resources.  the  They  the  revealing  potential  rate  construction.  of  of c o n s t r u c t i o n  information  are  useful  activities  for tracking  delays  also  and  A  and more  provides  controlling  resources.  rarely  systematic  although  who  Day-to-day o p e r a t i o n a l plans are  field  i n a much more d e t a i l e d breakdown of c o n s t r u c t i o n as  them  provides  construction  the  delays  activities  detailed  also  focus  the  are  seguence  information  required  must  with  resource  such  F i e l d management personnel,  management and  work,  tactical  higher  used, such  deadlines  towards  expected a  Such  PLANNING  methods being  construction  objectives are  provided  CONSTRUCTION  path method, p r o v i d e  information  personnel  TO  construction planning  the c r i t i c a l  goals  APPROACH  considered manner.  and  Rather,  and m o d i f i c a t i o n  of c o n s t r u c t i o n  studied they  detail  are e i t h e r  of past  s i t e managers and c o n s t r u c t i o n  in  methods  activities and  implicit  in a i n the  or developed  superintendents  by  i n the f i e l d  3  during  c o n s t r u c t i o n of the f a c i l i t i e s . D e t a i l e d d e s c r i p t i o n s  of day-to-day c o n s t r u c t i o n operations key  site  personnel.  managers  and  experience project  It  is  construction  and  in  skills  an  r e s i d e i n the minds of  generally  accepted  superintendents  to  efficient  achieve  the  manner.  that  will goals  However,  have set  the  tied  to  advance  tradition in  usefulness  1.2  these s k i l l s  and  historical  construction of past  enough  for  the  management  t r a i n i n g environment through which s i t e management are expected to a c g u i r e  site  personnel  i s extremely uneven precedents.  technologies  often  The  and  rapid  reduces  the  experience.  REPETITIVE  CONSTRUCTION AND  Repetitive  construction  CONSTRUCTION  projects,  which  PLANNING  include  mass  housing development, h i g h - r i s e b u i l d i n g , highway, bridge tunnel for  projects,  a  l a r g e number  repetition  be  of  typical  however,  progresses. building, be  resulting t imes.  by  standardized  s e c t i o n s . The  types allow  high  savings  that  propagate  and  result  from  magnify  For example, i n the p r o d u c t i o n savings  in  multiplied  the  construction  thirty  from poor p l a n n i n g  times;  idle  design  degree  i n cost  through h i g h l y d e t a i l e d c o n s t r u c t i o n  m u l t i p l i e d ; problems  will,  will  characterized  i n these p r o j e c t  time achieved to  are  time  and  poor  planning  a  project  as  a  of  planning  of a t h i r t y  of  and  typical of  story floor  resources  w i l l a l s o be m u l t i p l i e d  thirty  4  1.3  NEED FOR  ACTIVITY  D E S I G N TOOLS FOR  FIELD  MANAGEMENT Existing  planning  management at meet  the  site. the in  the  needs  problem  construction  of  industry  and  levels f a i l  Dabbas and  the  recognized  by  p r a c t i t i o n e r s in  and  has  [98]  methods  calculation  construction  been addressed by stated  [27]  "Methodologies  in  its  consideration  for  at are  the  l e v e l of  less  analyzing  field  abundant.  a t t e n t i o n as higher  little  traditional to  construction a c t i v i t i e s construction problems  particular,  when  not  i n order  they  Also,  the  as  much  in  planning  the  design  does of  to b e n e f i t from advances i n this  actually  approach arise  c o n s t r u c t i o n process when i t i s o f t e n e i t h e r too c o s t l y to make changes.  for  [27]  to c o n s t r u c t i o n  innovations  control at  received  l e v e l systems."  technologies.  only  problems  systems  operations  have  approach  encourage  address  d e c i s i o n making and In  level  that:  which  construction  technological  The  systems  the  [98]  further stated  and  authors  that:  includes  any  process on s i t e . "  Halpin  to  at  s o l v i n g the p r a c t i c a l o r g a n i z a t i o n problems of production  for  management  network  and  originated  project  l i t e r a t u r e . Peer  the  algorithm  of  i s well  the c o n s t r u c t i o n "None  which  organizational  detailed  This  models  deals  with  during  the  l a t e or  too  5  To  encourage  the  activities  before  deal  problems  with  detailed  resources  design  of  are a c t u a l l y  before  they  arise  construction  committed in  the  and to  field,  a  p l a n n i n g system which c a t e r s to the needs of s i t e management personnel must be developed. provide  information  Such a system should be able to  useful  for tracking  v a l u a b l e resources, should be easy to  respond  to the dynamic  and  controlling  to use and should be able  environment  of the c o n s t r u c t i o n  site.  1.4  RESEARCH  OBJECTIVE  AND  APPROACH  The o b j e c t i v e of t h i s t h e s i s design of a computerized construction  environment f o r d e t a i l e d  activities  associated  with  repetition.  The  with  projects activity  design  plans  design  goals  would  also  to  creativity  i n the a c t i v i t y  thesis In problem  chapter  two,  design of activities  by  significant would  assist  to s y s t e m a t i c a l l y analyze resulting  in  tactical  s e t f o r a c o n s t r u c t i o n p r o j e c t . The  personnel  In  apply  on  environment  construction a c t i v i t i e s  to achieve  environment  emphasis  characterized  c o n s t r u c t i o n management personnel and  i s to develop a conceptual  allow  personal  construction judgment,  management  intuition  and  throughout  the  design p r o c e s s .  the terminology  used  i s presented. chapter  three,  in high-rise  the  construction  cycle  planning  c o n s t r u c t i o n p r o j e c t s i s d e s c r i b e d to  6  gain  an  understanding  involved  of  the  difficulties  and  complexity  in designing a construction a c t i v i t y .  In  chapter  planning  four,  described  studied  to  activity  design.  in  the  determine  In chapter described  existing  five,  in  the  models  literature  their  for  construction  are  reviewed  applicability  the assembly  industrial  line  and  for  detailed  balancing  technigue  engineering  literature  is  s t u d i e d to determine whether i t can be adapted f o r design of construction In  activities.  chapter  d e c i s i o n making  six, a  brief  overview  solution Finally,  environment formats  problem  analysis, a  and  the  i s d e s c r i b e d . Then, the process  design i s d e s c r i b e d by flow c h a r t s and recognition,  of  definition,  and  design  conceptual i s described interaction  solution  of  an  i n terms of between  of  of  activity  f i v e modules: problem  improvement  design  process  and  enrichment.  activity  computer  the  formulation,  design  input/output  computer  and  the  d e c i s i o n maker. Chapter  seven  presents  thesis  recommendations f o r f u t u r e r e s e a r c h .  conclusions  and  7  2.  TERMINOLOGIES  One of the f i r s t construction  planning  terminology In  this  with  construction  the  lack  to d e s c r i b e  the terminology  process  will  be  the  LEVELS  management  hierarchical  structure  the  concerns  of management  the  construction  At  consistent processes.  level  site.  IN  and w i l l  be  used  with two  used i n the a c t i v i t y  described.  CONSTRUCTION  of  the  of the p r o j e c t  i n t h i s t h e s i s . Terminology a s s o c i a t e d  HIERARCHICAL  i n t o three  a  for describing  introduced  design environment w i l l a l s o be  In  of  used  approaches to work breakdown s t r u c t u r e s  2.1  i n the study of  construction  at the p r o d u c t i o n  hierarchy  consistently  is  which  chapter,  management  problems encountered  MANAGEMENT  construction  projects,  a  e x i s t s because of the d i f f e r e n c e s i n personnel  The h i e r a r c h y  at head  can be roughly  l e v e l s : o r g a n i z a t i o n a l , p r o j e c t and  the o r g a n i z a t i o n a l  level,  office  management  and at divided  production. i s concerned  with the l e g a l and business s t r u c t u r e of a f i r m , the various f u n c t i o n a l areas head o f f i c e functions.  of management, and the i n t e r a c t i o n between  and f i e l d It i s also  management personnel performing  these  concerned with  total  the a p r o j e c t ' s  8  cost, of  duration,  other  the  project  definition,  breakdown resource  the  (1)  into  and  to the  i s  legal  activities  at the production  selection  portfolio  concerned  with  o b l i g a t i o n s , and f o r time,  of  level,  i n chapter  efficient  t h e commitment  the production  level  which  one,  cost  and  of resources  i s described  i s concerned  construction  of c o n s t r u c t i o n a t the s i t e .  methods  three  is  and  and  and t h e d a y - t o - d a y  Construction  can i n v o l v e  with  levels  planning  of  detail:  Activity An  activity  element  of  purpose  a of  usually the  time  related  physical  activity example  is  a  project.  planner/scheduler,  time  resource  I t i s normally and  cost  estimator,  or  facility unique  by and  of a t h i r t y  a  defined  cost  sequence  must  consuming f o r the  control  to the construction  of an a c t i v i t y  structure  (2)  management  contractual  management  technologies,  at  in relation  control.  site/field  progress  level,  of t h e p r o j e c t  Management as  flow  projects.  At project  and cash  be  by  engineer. of  a  a  It i s  division  of  of o p e r a t i o n s .  An  completed  i s the completion  of  once. the  An  floor  story high-rise building.  Operation A  construction  of  work  tasks  is  closely  operation  r e l a t e d t o each  related  represents other  a  collection  technologically.It  to the construction  method  and can  9  be r e p e t i t i v e is  measured  operation using  i n nature. in  The d u r a t i o n  hours  or  i s the forming  say  a  tower  days.  of an o p e r a t i o n  An  example  of  of a s e c t i o n of a f l o o r 2  crane,  general  an  slab 10  labourers,  carpenters and 1 foremen. (3)  Work  Task  A work task construction into  i s the b a s i c d e s c r i p t i v e u n i t  process.  components,  detailed should  a  construction clear  readily  any  grasp  a  i s broken down  considerations  component  Its description of  a  and v i s u a l i z e  or  what  of  must  construction  task  be  crew  i s involved  a so  can  i n the  are t h e r e f o r e the b a s i c b u i l d i n g  of o p e r a t i o n s .  installing  factor  identifiable  member  work task. Work tasks blocks  task  motions are i n v o l v e d . A work  operation.  that  readily  human  eguipment be  I f a work  of the  support  An  example  bracket  of  of a work  task i s  a  of  section  slab  formwork. Another assignment  term  that  which  is  will a  be  collection  operations s p e c i f i c a l l y assigned Of production  the  hierarchical  level  is  problem. D i s c u s s i o n s production  level.  in this of  work  thesis i s tasks  or  to a crew member or a crew.  levels  pertinent  in this  used  to  described, the  thesis w i l l  only  activity  concentrate  the design  at the  10  2.2  TERMINOLOGY FOR Information  INFORMATION  REPRESENTATION  r e p r e s e n t a t i o n i s one of the most  important  elements i n any problem s o l v i n g environment. In the a c t i v i t y design the  environment, which w i l l  physical  down  into  smaller  representing proper  this  being  terminology In  between  the  be  approach  the above  "Work  can  to  the  Structures  [64] d e s c r i b e d  subdividing  an  terminology  and  in  the  in  a work  in  effort [64]  is a  which  systematic a  physical  constructed.  to work breakdown s t r u c t u r e i n p h y s i c a l work  described  the a c t i v i t y design  structure  manner  f a c i l i t y and i t s components are  assemblies  provide  as:  approach  represent  The approaches  management  information.  Breakdown  words, a work breakdown to  in  to ensure  and  i n t o i t s components and/or end product." In other  broken  employed  computer  Ponce-Campos and R i c c i  systematic  be  consistent  literature,  to represent  breakdown s t r u c t u r e (WBS) "a  to  thesis,  work breakdown s t r u c t u r e s d e s c r i b e d i n  paper  Construction",  has  terminology  must  management  needed the  The  information  Systematic  construction  constructed  units.  communication  personnel. the  facility  be developed i n t h i s  categories  below  will  environment.  be  will used  be  adopted.  The  i n d i s c u s s i o n s of  11 2.2.1  WBS  The defining  IN  PHYSICAL  first  task  "ASSEMBLIES"  in any  problem  the problem in a clear  construction  project,  the  solving  and precise  problem  process i s manner. In a  definition  process  involves defining the dimensions of the physical f a c i l i t y in d e t a i l . The following  terminology w i l l  definition  activity  in  the  be used for problem  design  environment  physical  facility  being  developed. Total-Assembly:  denotes  the  delivered defined  to  be  at completion of the project  as  by the t o t a l  scope  of work  in the  contract documents. Assembly  Group:  denotes a grouping of physical assemblies  with  similar  significant structure;  functions portion  and  of  a  e,g superstructure,  represents building  a or  substructure,  south-wing, north-wing. Assembly:  denotes  a  meaningful  assembly  group;  subdivision  e.g. a floor  of  elevation,  an a  sub-grade elevation. Sub-Assembly:  denotes a horizontal d i v i s i o n  of an assembly  group or an assembly; e.g. the north-wing of the  superstructure,  elevation.  bay  13  of  a  floor  12  Assembly  ( s u b a s s e m b l y ) Component: denotes  one  of  the  components of an assembly (subassembly); e.g. slab,  columns,  walls,  and  cores  are  components of a floor elevation assembly.  2.2-2  WBS IN WORK/COMPONENT  "CATEGORIES"  Construction operations are labour intensive processes. Solution  formulation  work which  involves  defining  are to be performed can be  the operations or  to construct categorized  the physical  facility.  Operations  by  performing  the work or the physical components on which work  is being performed. The following terminology in the solution formulation process  the trade  will  in the a c t i v i t y  be used design  environment being developed. C a t e g o r y Group: denotes  a  disciplines concrete, Category:  grouping or  of  trades;  components  e.g.  by  civil/site,  metal.  denotes a grouping  of components by functions  under the same category group; e.g. under the category-group supported  of  concrete,  we  can have  slabs, grade slabs, cores, columns,  footings, and walls. C a t e g o r y Component: denotes the material or sub-component that  make  up  an  identifiable  project  13  component; e.g. in the concrete component we can  have  form-work,  rebar,  concrete,  and  process  in each  work  misc. metals. Category  Sub-Component: denotes  a  category  component;  composed  of  e.g.  [form-work  [form-work]  installation]  [form-work dismantling] processes.  is and  14  3.  CYCLE PLANNING  In  order  designing  a  decision  to  understand  construction  making  construction  IN REPETITIVE  be used  as an  activity  design  involved  example  to  problem. The t y p i c a l  building  identified  as a s i n g l e a c t i v i t y  design  construction  the a c t i v i t y  cycle  can  activity  and  construction  in this  project  problems  objective  discussed.  will of  Then, the design  studied. F i n a l l y ,  designing  the  complexity  construction is  therefore  activity. cycle  typical  projects  will  of  the  cycle in a  often  simply  network; f o r floor.  be  Thus,  design  The  identified the terms  will  cycle  be  used  first  in a high-rise building be  construction  described cycle  and  the  design  are  parameters and v a r i a b l e s w i l l be  statements w i l l be made regarding  of the c o n s t r u c t i o n construction  the  thesis.  construction  construction and  chapter  this  i n the p r o j e c t  of a c o n s t r u c t i o n  The t y p i c a l  in  project  with the design  interchangeably  in  of form and pour the f i f t h  of a c o n s t r u c t i o n  design  involved  in  illustrate  PROJECTS  process  in high-rise construction  high-rise  example,  the  activity,  process  cycles  CONSTRUCTION  cycle planning  c y c l e design  the goal  problem and the need of a  environment.  15  3.1  THE  T Y P I C A L  The  construction  construction  of  Construction major  C O N S T R U C T I O N  the  of  portion  construction  of  of  a  C Y C L E  high-rise building consists  substructure  the  superstructure  of  the  the  total  and often  can  (3)  mechanical,  structural  activities  activities  as  structural activities which are The  are  cyclic  (4)  the  most  of  out  operations  of  the  roughly  a  are  are c o l l e c t i v e l y c a l l e d  The  divided  building finishes.  The  significant proceed  group unless  The  sequence  repeated  the  of  operations  floor structure.  a  number  of  times  Because  of  sequence of  operations,  the they  the " t y p i c a l c y c l e " .  Since the f l o o r s t r u c t u r e s must be completed before other  activities  activities network.  mentioned  often  The  above  appear  rate  at  as  general their  fact  contractors  own  involve  This  which  has  a  begin,  typical  the  well  in  floor  the  other  groups  intermittent  use  of  special  to c o n t r a c t o r s s p e c i a l i z e d  of  the  structural  the  project  structure  recognized  structural  work-force;  subcontracted  the  f a s t the other a c t i v i t i e s  been  perform  can  "critical"  produced t h e r e f o r e governs how progress.  of  structural  i s completed.  repeated  a  (2)  to produce a t y p i c a l  building structure  nature  duration.  complete. by  for  (1) s t r u c t u r a l ,  cannot  are  characterized  carried  the  and  activities  components  sequence  until  other  form  accounts  be  i n t o the f o l l o w i n g groups of a c t i v i t i e s : electrical,  superstructure.  project  superstructure  of  and  activities activities  trades i n those  are  is can  most with which often  particular  16 areas.  Since  group  of  structural  activities  concentrate  3.2  the  activities  the  following  manager, c o n s t r u c t i o n  and sometimes  use  foremen w i l l  the  personnel  construction approach  to  a floor  resource  construction  methods.  f o r example,  pour f l o o r  a duration  the  construction  project  methods and  meetings,  construction planning in general  because  In  of  equipment met  the  at In  of f i v e  the  field  appropriate traditional  construction  the a c t i v i t y  cycle network  of form and  days. Even  though  are d i s c u s s e d  lack  of  a  manner. Problems  with  and documented  the chosen  in  proper  system, they are o f t e n mentioned analyzed  the  order  the  i n the p r o j e c t  technologies  terms, and are r a r e l y  a systematic  most  the  appears  as a s i n g l e a c t i v i t y ; s l a b with  the  planning,  often  the  i n terms  resources.  effectively,  choose  and  and  i s therefore  of the committed  technologies  manner  materials,  must  structure  meet to d i s c u s s how  effective  "time" o b j e c t i v e  committed  superintendent,  The major concern i s meeting  labour,  of the " c o s t "  management  for  The  to a c o n s t r u c t i o n f i r m , the  i n the most  money,  utilization.  to  the s i t e  criteria  time,  expense  will  PROBLEM  manager, s i t e  i s to be c o n s t r u c t e d .  the p r o j e c t of  critical  discussions  CYCLE PLANNING  Once the p r o j e c t i s awarded  buildfhg  the  on the s t r u c t u r a l a c t i v i t i e s .  THE CONSTRUCTION  project  form  only in  construction  17 methods and t e c h n o l o g i e s during  the c o n s t r u c t i o n  3.2.1  DESIGN To  DECISION  the d e c i s i o n  involved  process  i n designing  a  some of the parameters and d e c i s i o n of the c o n s t r u c t i o n  cycle  Cycle  and understand the  variables floor  activity,  i n the design structure  the t a r g e t  date  f i n i s h e d product,  management  must make a  floor, into  the  time  i . e . cycle  a  time-cost  reguired time.  proper operation eguipment  cycle  eguipment and forming The  cycle  time  material  and  labour  handling  decision  pool  a  a  typical  often  evolves  reduced  and increased  can  also  be  decision  through  selection  cycle  expensive overtime  shortened  to reduce i d l e time of of  by  labour  effective  technology. for  i n f l u e n c e and i s i n f l u e n c e d and  construct  problem:  time  planning and  f o r d e l i v e r y of  at the expense of more  eguipment, a l a r g e r labour However,  to  This  trade-off  time can be achieved  cost.  in a  discussed.  to meet  regarding  and  VARIABLES  Time In order  the  as they appear  construction  of a t y p i c a l  h i g h - r i s e b u i l d i n g p r o j e c t w i l l be (1)  only  process.  PARAMETERS AND  illustrate  complexity  are d e a l t with  a  floor  structure  will  by the s e l e c t i o n of forming  technologies,  usage and seguencing of  material, operations.  eguipment  18 Forming  Technologies  Formwork cost represents variable It  portion  normally  of  accounts  concrete  placement  rigidly  specified  normally do not concrete  for  cost  33%  concrete  vary  to any  division  and  the to  structure  55%  of  and  cycle. total  cost  of  reinforcing  s i g n i f i c a n t extent.  of  most  the  [25]); the  the  steel Cost of  over-time, e f f i c i e n t  handling  the  proper sequencing  allocation  material  r e l a t e d to the  of the major and  in  (Fintel  e f f e c t i v e use  appropriate are  cost  placement depends on  operations, space  the  one  and  work  selection  equipment,  a l l of  forming system s e l e c t e d and  of  of  which  how  the  system i s implemented. Conventional normally  only  forming or formwork.  in  the In  entire  story  passed  up  low-rise  be  to the  complicated  building  after  and  floor the  is  simple,  i s not  later  through  concrete  undemanding projects  f e a s i b l e , an  disassembled shafts  has  used  non-reusable  construction  equipment  formed  next  formwork  extreme of  lifting  may  building  minimum  highly  opposite  where expensive  the  built-in-place  or  and  outside  acquired  the  strength.  Reusable projects  such  economy of  the  formwork as  is  used  high-rise  formwork w i l l  cost  of  formwork,  either  cost  of  non-reusable  large  building depend  rental  parts,  in  (3)  or  on:  repetitive  projects. (1)  custom  number of  the  The first  built,  (2)  reuses,  (4)  19  cost  of  erecting  cleaning, forming  sections  their  and  indicated  their  proper  of  as  the  equipment  purposes  tower  of  ganging  shoring  time,  of  system i n terms  and  labour  operations.  which  building areas  required  the  they  are  prohibit  reach  of  is  crucial  to  For  locations  use  the  choice  intended.  their  the  lifting  conditions  of  equipment, only with  of and  most  in  mobile  Capacities  of  size  of  the  one  large plan  necessitates  Conversely,  the  major  site  the the  use  busy  crane;  capacity  formwork  i s normally  areas  of  lifting  be governed by the maximum reach and lifted.  of  has  tower cranes are most o f t e n used. Being  in projects  tower cranes.  on  projects,  expensive p i e c e  used except  crane  projects  of a p r o j e c t . The  depends  for  consequently,  limit  cost  studied  cost,  scheduling  cost performance  commercial  be  The  in h i g h - r i s e construction  such  high-rise  an  of  impacts on other  that  eguipment  the  (5)  Transportation  Experience  lifting  choice  v e r t i c a l ) must a l s o be  reguirements and Materials  and  modifications.  the  implications  time and  stripping,  r e p a i r i n g , and  ( h o r i z o n t a l or of  and  two  and or  equipment  the more will  weight r e q u i r e d of  sections  the that  to  crane  may  can  be  transported. The transport concrete  lifting of  equipment  heavy  forming  will  be  sections,  used  for  the  prefabricated  or r e i n f o r c i n g s t e e l components, and  placement  20  of concrete  when a crane  Most of these o p e r a t i o n s  and  bucket  are c r i t i c a l  c y c l e . Thus c a r e f u l p l a n n i n g and schedule  system  i s chosen.  i n the s t r u c t u r e  study of the equipment  i s r e q u i r e d to a v o i d delay  or i n t e r r u p t i o n  of  operations. Concrete  Placement  Next costly  to  item  placement economy  the  and  is  method and  efficiency of  formwork, concrete labour  has  a  quality  intensive.  significant  of  the  of the o p e r a t i o n  rate of placement  per u n i t  time.  The  most  placement  are  hoists.  For  large  material  hoists,  i s the most  The  choice  impact  concrete  used  crane  and  projects,  the  placed.  The  i n terms  concrete  placed  systems  of  concrete  bucket,  and  material  integrated  conveyor b e l t s ,  of  on  i s o f t e n measured  i n volume of  frequently pumping,  placement  and  systems  motorized  of  buggies  might be used. The  use of h i g h - e a r l y s t r e n g t h concrete can  the c u r i n g time and be  reused  more  significantly and  finishing.  selection testing  to  of  thus allows the forms and  o f t e n . Use  reduce In  the  fact,  concrete  determine  of time  reguired  additives  design of the s t r u c t u r a l  cycle.  shores  super-plasticizers  decisions  strength  reduce  can  for  be  will  placement  p e r t a i n i n g to and  to  the  non-destructive central  to  the  21  (5)  Prefabrication  of  Components  Prefabrication  of  s t r u c t u r e components,  such  as  concrete s t a i r w a y s , column r e i n f o r c i n g s t e e l cages,  and  use of welded r e i n f o r c i n g  s t e e l mesh, o f t e n allows  the  corresponding  to  operations  efficient  manners  by  parallel  rather  than  be  carried  allowing  them  out  to  sequentially.  in  more  proceed  in  Prefabricated  components, however, need to be t r a n s p o r t e d to the work l o c a t i o n and for  use  of  thus have to compete with other o p e r a t i o n s lifting  components and site  areas  equipment;  moreover, p r e f a b r i c a t e d  on-site prefabrication  needed  for  material  processes  storage  occupy  and  other  purposes. (6)  Breakdown and  Sequence of  Decisions transportation, determine reguired choose  to  and  made and  be  then  half place  a  floor,  the  rest  made f o r other elevator cores.  the can  the  of  the  the  list  The  floor  decide  the  operations  of  i n which  to form  or  he  operations maker  and  as  can  smaller  they  are  the whole  can  similar  such  technologies  decision  concrete,  floor;  material  structure into  sequence  concrete  place  placement  out.  down the  decide  place  forming,  extent  carried  c o n s t r u c t e d . He  and  on  concrete  some  to break  sections be  to  Operations  decide  to  then  form  to  floor form  d e c i s i o n s can  c o n s t r u c t i o n of  and be the  22  Decisions broken sets  down of  on  and  transitions  required.  operations between  time f o r labour and (7)  Scheduling  of  come on ready  for  up  impose  Number  of  arising  tasks the  and  in  of  the  minimize  idle  though  and  from  not  distinct  space  during  the  be  scheduled  to  must  operations. limited  product  to  the  is  Conflicts  work space  equipment must be avoided  on  Sizes,  forming,  the  sub-trades  Crew  material  breakdown  the  in  and  technologies,  set  construction  involved  requ i red.  Crew  define  labour  to  partly-finished  costs  placement  components,  involved  of  and as and  to the general c o n t r a c t o r .  Decisions  together  number  c o n t r a c t o r s , are  particular  delay  Crews,  concrete  be  to ensure smooth  sub-trades,  Sub-trades  need f o r the same l i f t i n g  (8)  and  time  only when the their  subsequently  the  to  resources.  by  general  take  between sub-trades  they  is  sequencing  i s necessary  equipment  process.  site  determine  operations  by  which  construction  structure  Careful  performed  in d e t a i l  operations  floor  Sub-Trades  Operations studied  the  constructed  forms  corresponding  how  each  types, and  of  of of  Mix  handling,  prefabrication the  floor  operations  the  floor  operation  the s i z e s and  and of  structure and  tasks  structure.  subseguently  The  define  mixes of each crew  23 The desired  production cycle  proportional used  rate  time  required  will,  to the crew  to speed  to  achieve  up  to c e r t a i n  size.  Multiple  up the c o n s t r u c t i o n  limits,  the be  crews  can be  operations,  but at  the expense of more s e t s of forms and more crowded work space. Extra to  shorten  shifts  and/or  c y c l e time  over-time  can a l s o be used  but not without  the a s s o c i a t e d  costs. Use  o f R e s o u r c e s and Crew A s s i g n m e n t Given  must  the pool  determine  equipment  the schedules  member  of  pool  resource  crew  p r o d u c t i v i t y r a t e with  the d e s i r e d p r o d u c t i o n given  a  and/or  major  f o r each so  as  p i e c e of  crew and each  to achieve  the  maximum e f f i c i e n c y . I f  r a t e cannot be achieved  of resources,  pool  the d e c i s i o n maker  f o r each  and work assignments  individual expected  of r e s o u r c e s ,  changes  with the  i n the s i z e  i n the c o n s t r u c t i o n  of the  technology  must be contemplated. Operations scheduled be  use  made on the p r i o r i t i e s  limited  shared  resources  must  be  to minimize queuing d e l a y s . D e c i s i o n s have to  when c o n f l i c t s of  that  given  of equipment  work space,  to v a r i o u s  usage a r i s e .  the work schedule  must be c a r e f u l l y developed  operations  For the case of each  to avoid over-crowding.  crew  24 (10) I d e n t i f y i n g C r i t i c a l  Operations  and P r o c e s s e s  Once the construction operations and assigned that  to various crews and equipment,  are c r i t i c a l  smooth progress identified. and  and w i l l  operations  p o t e n t i a l l y disturb the  of the construction  Any expected  studied  have been defined  process  problems should  and the corresponding  must be  be  analyzed  correction  plans  developed, i f time and cost allow, before they actually happen in the f i e l d .  3.2.2  NEED FOR AN A C T I V I T Y  From  the above  DESIGN  discussions,  ENVIRONMENT  we  can i d e n t i f i e d the  following c h a r a c t e r i s t i c s of the construction  cycle  design  problem: (1)  multiple objectives: time, cost, and effectiveness and e f f i c i e n c y of committed  (2)  resources;  trade-offs between multiple objectives such as time and cost within product quality constraints;  (3)  a  large  number  technologies,  of  variables,  choice  of  construction  as  choice  methods  of and  sequence of operations,  and the commitment and use of  resources,  determine the effectiveness of  that together  the subsequent production (4)  such  schedule;  a large number of possible values for each variable and a large number of feasible variable value combinations.  25  The u l t i m a t e o b j e c t i v e of the c o n s t r u c t i o n c y c l e design process time  i s to maximize p r o f i t s  and  cost  evaluation because and  of  the  effective  because of the  design  between  inability  f u n c t i o n that  selection  This  not  However, known  the d e c i s i o n  do not have a c l o s e d form  a l l the  design  v a r i a b l e s and  the design o b j e c t i v e . An optimal s o l u t i o n cannot be  obtained  by a d e t e r m i n i s t i c mathematical p r o c e s s . The problem must solved  by  management  objective  and  the  personnel complex  who  the  design  between  the  design  linkages  i n the s o l u t i o n design  Although available  to  p o s s i b l e to c r e a t e an management  The  of  planning five.  can  generate  conceptual  environment review  and  will  be  modeling and  best  design  environment  personnel  alternatives field.  the  described techniques  industrial  explore  a c t i o n plan  design  of is  alternative,  i s not i t is  i n which the c o n s t r u c t i o n  readily an  and  process.  a d e t e r m i n i s t i c mathematical procedure determine  be  understand  v a r i a b l e s , and by a p p l y i n g experience, p e r s o n a l judgment intuition  a  the  precisely  to d e f i n e a l l of  link  of  require  alternatives.  them are  v a r i a b l e s i n q u a n t i t a t i v e term, we production  the  solution.  a l l possible  linkages  through  to be  engineering  design  used  i n the  an ' a c t i v i t y  chapter  being  the  used in  six,  design  after  the  in construction  chapters  four  and  26  4.  E X I S T I N G MODELS FOR  In  order  to  develop  a  CONSTRUCTION  construction  PLANNING  cycle  planning  framework, the e x i s t i n g models used i n c o n s t r u c t i o n will  first  be reviewed  detailed construction  4-1  DETERMINISTIC  4.1.1  BAR  The Gantt  to determine t h e i r cycle  design.  MODELS  (or Gantt)  chart  the e a r l y 1900's. The b a s i c  of work to  monitor  and  introduction,  that  portraying  must and  track  status  (2)  project  many  plans  to  of  the bar chart in  followed  Henry  L.  management  in  has  work  item  represents  i n order  enable  the  and  received  work  (activity) the planned  with  the  project.  disciplines  modeling concept of the bar chart  length  production  by  i n t e n t i o n s a r e : (1) to s e t down  be  fruition,  management  project  developed  ( i n f l u e n c e d by t e c h n i c a l r e s t r i c t i o n s ) , stages, or  project  from  was  (1861-1919) f o r i n d u s t r i a l  phases  applicability for  CHARTS  bar  the steps  planning  wide for  progress.  to b r i n g planner Since  duration  scaled  to its  acceptance graphically The  i s the r e p r e s e n t a t i o n a time  a  basic of a  bar whose  of the work item. I t  27  can  be l o c a t e d  starting, it  i n calendar  execution  represents.  a graphical  and completion  The s c a l e d  management  o v e r a l l scheduling, The is  major  simple  item. Ingenious use of the bar chart  with  useful  of  project  to understand  hierarchy.  information  and  model  personnel at a l l l e v e l s i n  involved  and  The  nature  of the i n t e r - r e l a t i o n s among work  be  deduced  inadequate  general,  Used  by  solving  management  construction  sophisticated chart  users.  models  itself,  the  complex  personnel  often  projects  are now  and  output  the  the  and  representation,  Whitetaker the fenced  retains  the s i m p l i c i t y  network  logic  techniques activity  bar charts  items.  items have to bar  chart  face  that  today.  analyzed  using  i s displayed  is  In more  i n bar  personnel.  devised  a  graphic  ( f i g u r e 4.1), which  of the bar chart model but shows the  i n precedence  including  chart  rationale.  found  [83]  work  problems  format f o r easy understanding by f i e l d Melin  to show  construction  the i n t e r - r e l a t i o n s of p r o j e c t  for  construction  fails  i n the  operations  by  i s that i t  update, and thus has  However, the model  the t e c h n o l o g i e s  on  and p r o d u c t i v i t y .  advantage of the bar chart  used by c o n s t r u c t i o n  management  details  item  of the bar i s a l s o used as  use of resources  and easy  been widely the  length  of the p r o j e c t work  base on which to p l o t a c t u a l performance toward  completion of the work provides  time to i n d i c a t e the schedule f o r  the  have t h e i r  or arrow  1ine-of-balance  origin  diagrams. Other and  i n the bar chart  multiple modeling  28  S MOVE  15  IN  [7 C L E A R B I ORDER  16  EXCAVATE  AND D E L . REBRR  ANO P E L .  ROOF 17  SITE  10 P L A C E  E 3 ORDER  PLACE  11  STRUCT.  INSTALL  INSTALL  E0U1PTMENT  UlNDOUslia  C L E A N UP  fTEBPfl  CAST  FOOTINGS  STEEL  13  ERECT  M  POUR  URLLS  •itl  4. ORDER  ANO D E L .  UIN00U5  5 ORDER  ANO D E L .  EQUIP.  8 15 JAN79  22  Figure  29  FLOOR  "itl.  5 12 FEB79  19  4.1:  Fenced  Source:  Melin  I<IIIIIII  26  S 12 MAR79  19  bar chart  06  9  0  9 10  16  23  30  of a warehouse  7 H MAY 7 9  project  [ 8 3 ] , p . 501  POUR FLOOR  3  07 10  CLEAR SITE .  MOVE IN  2 9 APH79  and W h i t e t a k e r  ORDER REBAR S  0  26  10  3  5  li  10 oe 20  29 10 30  EXCAVATE  PLACE REBARS  H  10 25  25  40 13 69 CAST ROOFING  9 30  PLACE ROOF 69 10 75  0  0  04 99  65 16 70  0  ORDER WINDOWS  INSTALL WINDOWS  19 99 70  70  4.2: Source:  Precedence Melin  diagram  '  of a warehouse  and W h i t e t a k e r  CLEAR UP  5 75  ACTV ITT DESCRIP.  ORDER EQUIP.  Figure  INSTALL EQUIP.  40 29 69  9  ORDER STEEL  69 19 79  ERECT WALLS  ES - EARLY START EF - EARLY F I N I S H 10 • ACTIVITY IDENTIFICATION L F - LATE F I N I S H LS - LATE START DU • ACTIVITY DURATION TF - TOTAL FLOAT  project  [ 8 3 ] , p . 500  29 4.1.2  CRITICAL PATH METHOD The  E.  critical  Kelly  of  represents the  (CPM)  path method, o r i g i n a t e d  UNIVAC  and  a project  Morgan  plan  by  a  R.  Walker  network model  l o g i c of the c o n s t r u c t i o n p l a n . Two  precedence  of  duPont,  that  depicts  types of graphs,  former  techniques  to  assign  such  a  wide  that  The a  figure  network  variety  spectrum  of  of  4.2)  and  the  ( a c t i v i t y on arrow) diagrams have been used, with the preferred.  node,  James  arrow  being  on  by  the  now  (activity  i n 1957  model  uses  a t t r i b u t e s to  problems  can  labeling the  be  model  treated  graphically. Preparing  a CPM  network u s u a l l y  involves  the  following  steps: 1.  List  2.  E s t a b l i s h the for  the a c t i v i t i e s  each  (or work  durations  of  items). and  the  resources  reguired  activity.  3.  Develop the network l o g i c ,  i . e . precedence r e l a t i o n s .  4.  F i n d the c r i t i c a l  non-critical  5.  On  path and  a time frame, develop resource  each type of resource 6.  Level  resources  paths.  usage histograms f o r  f o r the whole p r o j e c t .  within  acceptable  limits  for  the  project. 7.  Re-schedule s t a r t  times of  activities  to s u i t  resource  leveling. 8.  I t e r a t e through is  achieved.  3 to 7 u n t i l  a "satisfactory" solution  30 The major advantages of the c r i t i c a l  path method are as  follows: 1.  Logic  restraints  are  whereas assumptions  clearly  shown  on  the  diagram  were necessary when bar c h a r t s were  used f o r c o n t r o l . 2.  I t s t i m u l a t e s more d e t a i l e d which  usually  d e l a y s , fewer 3.  results  in  p l a n n i n g by better  coordination,  claims and e a r l i e r p r o j e c t  I t permits e v a l u a t i o n of the impacts actual  the c o n t r a c t o r  changes  of  project  fewer  completion.  of a n t i c i p a t e d  conditions  and  on  the  c o n t r a c t o r ' s work. 4.  I t can be used to p r o v i d e progress and payment data.  5.  Updating  permits  delivery  dates  completion 6.  method,  it  personnel diagram  with  by  the  final  path method i s packages  integrate  the  project  m a t e r i a l procurement,  cost  scheduling control  and  functions.  the has  because  and  and  i n the c o n s t r u c t i o n i n d u s t r y . S e v e r a l  packages  accounting Despite  advantage of the c r i t i c a l  f o r use  these  function  f o r owner f u r n i s h e d items  access to numerous computer software  developed of  of occupancy dates, needed  dates.  An a d d i t i o n a l the easy  refinement  numerous not of  advantages  been  welcomed  its relative  i t s modeling  of  rules  u n t r a i n e d p e r s o n n e l . Updating  by  critical  many  be  path  construction  complexity.  cannot of  the  The  network  easily  understood  the p r o j e c t  network i s  31 also  tedious  f o r large  redrafting  and  assistance  of  printout  projects.  computational computers,  generated  comprehensible  by  Even  work  the  when  much  i s performed  vast  amount  with  of  i s not welcomed and i s o f t e n site  personnel.  Birrell  of the the  computer  not e a s i l y  [11]  criticized  the c r i t i c a l path method f o r not being able to represent the more r e a l i s t i c  4.1.3  " h e u r i s t i c " process of c o n s t r u c t i o n p l a n n i n g .  LINE-OF-BALANCE The  line  developed applied where  of balance  the  is a  objective  products  manufacturing was  scheduling  i n the LOB technique:  (1)  The p r o d u c t i o n represents operations is  reguired  to  evaluate  diagram,  the  the  as shown  inter-relations  for a single  the  constraints  unit  flow  Three  of  diagrams  the  of  the  are  4.3(a), assembly product.  on the o p e r a t i o n s and shows the o p e r a t i o n s  to produce  a single  unit,  such  as a  used  the planned  plot  time.  For a mass  number  housing  of  typical  project.  diagram, as shown i n f i g u r e  versus  of  technological  The o b j e c t i v e to  rates  of the f i n i s h e d  representation  first  control  in figure  f l o o r s t r u c t u r e of a h i g h - r i s e b u i l d i n g (2)  technique  and p r o d u c t i o n  in a production l i n e .  used  It  (LOB)  by the U.S. Navy i n the e a r l y 1900s. I t was  to i n d u s t r i a l  finished  (LOB)  4.3(b), i s  units  produced  development  project,  32 the  objective  diagram  may  housing u n i t s produced (3)  The  progress  indicates  the  subassemblies  the expected  as  numbers  of  shown units  should  be  in figure  4.3(c),  for  of  represents  diagram; number  the of  produced  an  length  units  to date.  "line  of balance"  from  the  of  of  a  the  bar  the  by  and  each  i n the p r o d u c t i o n  indicates  the  line),  of progress date  actual  subassembly  i s compared a line  objective  particular  the  specific  bar graph;  corresponding  (or balance  to the l e v e l at  shown  A c t u a l progress  production  corresponds operation  operation  each  completed  dates. I t takes the form of a v e r t i c a l bar  number of  i n each week or month.  diagram,  which  show  to the produced  diagrams. needed to  It  f o r each  achieve  the  objective. The current  line status  of balance of  an  activity  s t a t u s so that c o r r e c t i v e when r e q u i r e d .  method  action  focuses relative  on monitoring the to  i t s scheduled  can be i n i t i a t e d  where and  33  -V  0 Months  prior  Figure  to  unit  Purchase  -v—A  m-  | Subcontract  1  part  part  \ ^  Subassembly  / \  Unit  completion  completion  completion  4.3(a):  Production  diagram  - - 70 - -  Feb.  1  Fig 4.3(b): Objective  Figure 4 . 3 :  diagram  Fig 4.3(c):  Line-of-Balance  Source:  Johnston  Progress diagram  modeling  [57], p.  250  technigue  34  4.1.4  TIME SPACE SCHEDULING METHOD (TSM) The  and  time  Cacha  "linear  space  s c h e d u l i n g method  [123], has  scheduling  been l a b e l e d  method  by  (LSM) "  d e s c r i b e d by S t r a d a l other  authors  (Johnston  [57]),  also  as  "linear  planning chart" (Russell  [114]), " v e r t i c a l p r o d u c t i o n method  (VPM)"  and  (O'Brien  [23]).  This  the LOB  scheduling  technique. TSM  objective emphasis label  [93]),  diagram on  the  "flow  technique  planning  balance  line  "Time Space S c h e d u l i n g  where  each  has  emphasizes  for  s c h e d u l i n g technique  line  some  a diagram  purposes  of  the  activity  similar  while  to the  places  diagram.  The  because  the  locations  take  to  LOB  i s chosen  the  (Cormican  relationship  progress  Method"  shows c l e a r l y  corresponding  method"  place  or in  "space" a  given  location  where  "time". The location  TSM  diagram  graphs  time  versus  i s e s s e n t i a l l y a measure of p r o g r e s s . L o c a t i o n  can  be measured i n many ways. In h i g h - r i s e b u i l d i n g p r o j e c t s the measure  is  floors  whereas  projects  the a p p r o p r i a t e u n i t  measured  i n terms  of  mass  housing  i s housing  hours,  a p p r o p r i a t e to the p r o j e c t i n the  in  days,  time and  development  u n i t s . Time can  be  weeks, or months, as  is  l e v e l of d e t a i l d e s i r e d  schedule.  Stradal  and  Cacha  [123]  has  described  diagrams f o r s t u d y i n g the e f f e c t of double  the  use  s h i f t s and  of  TSM  change  in p r o d u c t i o n r a t e s of c o n s t r u c t i o n o p e r a t i o n s on the number of  formwork  sets  diagrams to study  required. the  floor  O'Brien  cycle  of  [93]  has  a high-rise  used  TSM  building;  35  the a v a i l a b i l i t y of s c a f f o l d i n g f o r b r i c k l a y e r s and requirement  f o r sheetrock c o n t r a c t o r s were s t u d i e d and r a t e s  of progress of d i f f e r e n t a satisfactory  which  Further,  it  the  trades were synchronized to produce  schedule.  The most s i g n i f i c a n t with  close-in  can  advantage of TSM  convey  a  responsibilities  be separated and  detailed of  i s the  simplicity  working  schedule.  individual  crews  can  represented by t h e i r corresponding  also  progress  1 i nes. Authors importance time  who of  advocate  "balanced"  for valuable  level,  the  use  production  resources  it  is left  lines  indicates  of progress f o r v a r i o u s a c t i v i t i e s the  TSM  i s minimized.  the Time-Space diagram  model i n d i c a t e s  of  the  stress  the  that  idle  such At  the  activity  "desired" rates  (see f i g u r e 4 . 4 ( a ) ) . T h i s  " d e s i r e d " end  result  to the management. One  but how  disadvantage  to achieve of the  s i m i l a r to that of the bar c h a r t model, i s the d i f f i c u l t y identifying  logic  relationships  disadvantage  of  i s that  TSM  confusing  to  activities  is large,  and  when  untrained  production  (see f i g u r e 4 . 4 ( b ) ) .  the  between a c t i v i t i e s .  i t can  personnel sequence  rates  vary  the  of a c t i v i t i e s  from  location  of  Another  become complicated when  TSM,  number  and of  i s complex to  location  36  F i g u r e 4.4(a): Source:  A simple Time-Space diagram O'Brien  [93], p.  115  DAVf  F i g u r e 4.4(b): Source:  A more complex Time-Space diagram  S t r a d a l and Cacha  Figure  4.4:  Time-Space  [123], p.  diagrams  454  37 4.1.5  MULTIPLE ACTIVITY AND Halpin  Activity  and  Chart  with crew a l l o c a t i o n s h a n d l i n g systems. A vertical  bar  [43]  Woodhead 4.5)  (figure  and  described  used  to  the  coordinate  Multiple activities  to schedule d e l i v e r y and  It consists  i s used  CREW BALANCE CHARTS  material  of a s e r i e s of v e r t i c a l  f o r each crew, h o i s t ,  bars.  or crane u n i t  i n v o l v e d . Each v e r t i c a l bar p o r t r a y s the work assignment schedule  f o r a labour  crew  or a major  piece  of  The work assignments f o r each crew or equipment such The  that  they occur  i n a common length  bars are then analyzed to see  l o c a t i o n s or i n use of shared Crew charts  Balance  except  operation  of  the a  Charts  represent  individual  sequences.  Crew  crew  crew  balance  similar  model  particular  rearranging  focuses and  member  charts  unnecessary  work  overload  on  each  can  idle  produce the most e f f i c i e n t These system and to  models  are  also  assignments evaluation contribution  to of  various operation  of  each  i s used  be  used  to and  f o r work  of the work crew crew be  members,  minimized  to  crew s i z e .  only  management  can  internal  assignments  to  time  conceptual models  i n c l u d e no q u a n t i t a t i v e  assist  of  activity  the  bar  work  assignments  and  cycle.  is conflict  to m u l t i p l e  improvement purposes. By changing the s i z e and  are arranged  equipment.  are  former  equipment.  or b u i l d i n g  i f there  and  to  They  sequencing  working  the  real  or a n a l y t i c a l techniques  determine  crews.  of  trade.  the are  and They  set  of  helpful the  work  in  total  provide a  the  labour clear  38 statement  of work  assignments and sequences not available  from other models.  Form Erection  Dismantling forms  Dismantle fcxmi B Area  Erect forms A Area  *  Unload  Inspect  R. Steel  Mortar Available*  Pour C  Concrete Bucket pour C  Finish  Lift lurms  •Clean up  Windows  Son  '  >  Slack C  I  Erect forms 8 Are*  *  > 1  Dismantle forms 0 Area  Slack D  Unload Erect forms C Area  n i  cS  R. Steel  Pour D  Concrete Bucket • pour 0  Unload Dismantle forms A Area  >-  *  Erect forms 0 Area  Finish  Lift forms  Clean up  Windows  Inspect  R. Steel  Pour A  Concrete Bucket pour A  Finish  Lift forms  Clean up  Windows  Inspect  R. Steel  Pour 8  Concrete Bucket pour 8  Sort  •  Crane  Inspect Sort Dismantle forms C Art*  Hoist  Concrete  ( Stack B  Windows  Steel Crew  Sort  Set windows  Mortar  Bricks Stack  Mortar  Masonry  Lay brick 0  Slack Layout /» Lay brick A  Set windows  Available  Stack  Mortar  Stack  Available Set windows  Mortar  Lay brick B  Available Bricks  Stack Layout C  Stack  Set windows  Layout f  Mortar  Lay brick C  Available  o Stack A  1  Finish  Lift forms  Clean up  Windows  Slack Stack  Layout D  'Available for other tasks.  Figure  4.5:  Multiple a c t i v i t y chart for a building cycle  Source:  Halpin and Woodhead [43], p 37  39 4.2  P R O B A B I L I S T I C MODELS  4.2.1  UNCERTAINTIES Probabilistic  planning  because  Uncertainties project  I N THE  models of  the  i n both  influence  CONSTRUCTION  have  dynamic  external  the  accuracy  d u r a t i o n s . Ahuja and Nandakumar list  of  stochastic  been  elements  used  ENVIRONMENT  for  construction  construction  and of  internal  environment. elements  estimates  for  [2] i d e n t i f i e d  that  affect  of a  activity  the f o l l o w i n g  the  accuracy  of  a c t i v i t y duration estimates: 1.  l e a r n i n g curve  11. foundation  2.  weather  12. design schedule  3.  space c o n g e s t i o n  13. drawing approval schedule  4.  crew absenteeism  14. i n s p e c t i o n schedule  5.  regulatory  15. i n e f f e c t i v e  6.  design changes  7.  economic  8.  labour unrest  18. t r a n s p o r t a t i o n schedule  9.  crew  19. union  problems  20. l e g a l  problems  requirements and  activity  rework 16. i n e f f i c i e n t level  interfacing  10. p r o j e c t complexity Carr included  [19]  included  learning  Nandakumar congestion,  [2]  included  supervision consultant  17. m a t e r i a l d e l i v e r y schedule  weather  curve e f f e c t s  crew  conditions  seven  absenteeism,  conditions in their  and  models.  elements regulatory  Ashley  [7]  Ahuja  and  (weather,  space  requirements,  40 design  changes  labour  unrest),  significant  and  which  QUEUING The  theory  word  in  considered earliest 1920. has  "queue"  line  analysis  various  machine  model  are c a l l e d  the s e r v i c e s  a  wide  inventory  computer networking,  system a f t e r  the r e q u i r e d  is  of  hauling  represented  individual  the customers; demanded  the network  according  l o a d i n g by a loader  across  telecommunications,  can be  services  fleet  of the  1909 through  repair/maintenance,  demand  a  is  s e r v i c e s f o r many d i s c i p l i n e s .  queuing  enter  Erlang  f o r many from  that  of a c t i v e r e s e a r c h . I t  disciplines:  of demand and s e r v i c e s . The  through  in  and queuing  the e f f e c t  situations  system  proceed  most  estimates  "line",  the groundwork  different  simplest  Customers may  the  situations.  remains an area to  traffic,  provide  and  Forecast).  means  various  of queuing  h o s p i t a l s , and counter  that  levels  be  duration  c o n t r o l and storage, m a t e r i a l h a n d l i n g ,  The  to  f o r analyzing  on  laid  applied  vehicular  i n French  has  to have  of  activity  techniques  Queuing theory  spectrum  considered  (PROject Duration  technigues  been  on  activity  MODELS  provides  waiting  economic  they  influences  t h e i r model PRODUF  4.2.2  rework,  to  items  the  are c a l l e d  needs  and  that  facilities servers.  at any p a r t i c u l a r  their  by a  server,  leave  the  s e r v i c e s are r e c e i v e d . An example trucks  (customers)  which  (server) - see G r i f f i s [41].  require  41 Queuing simple  theory  provides  mathematical  solutions for  systems and p r o v i d e s measures of e f f e c t i v e n e s s of the  system  being  modeled.  simple  concrete  Examples  delivery  system  of  these  in a  measures  for a  construction  type  project are: (1)  Average  number  of  units  i n the queue,  e.g.  average  number of concrete t r u c k s w a i t i n g to be emptied. (2)  The  average  waiting  time  or  delay  before  service  begins, e.g. the average w a i t i n g time f o r each  concrete  truck before i t i s emptied. (3)  The p r o b a b i l i t y than  some  truck  that  value,  the t o t a l  delay  can be  e.g. the p r o b a b i l i t y  has to wait  more than  greater  that a concrete  a certain  period  of  time  before i t can be emptied. (4)  Expected  idle  utilization tower  time  of t o t a l  of v a l u a b l e  service f a c i l i t y ,  resources  such  e.g. the  as labour  and  crane.  Through  study  of  these  system  efficiency  measures,  d e c i s i o n s can be made r e g a r d i n g : (1)  Securing a d d i t i o n a l s e r v i c e f a c i l i t i e s , additional  lifting  equipment  e.g. i n s t a l l i n g  (additional  tower  crane,  h o i s t , or using a concrete pump with higher c a p a c i t y ) . (2)  Rearranging  existing  service f a c i l i t i e s ,  e.g.  layout  delivery  routing  reduce  of  concrete truck w a i t i n g  time.  system  to  changing total  42 (3)  Establishing  a  schedule  to  service  facilities,  lifting  equipment  increase  i t s utilization.  Solutions  reduce  e.g. sharing with  t o simple  other  queuing  crews  models  solutions  queuing  situations  construction  readily  obtainable.  4.2.3  DISCRETE  Simulation performed the or  i s a  system  would  respond  are defined  functions There such  a s GPSS,  such  a s t h e CYCLONE  for  planning and  problems  projects. such  and scheduling  construction  (Halpin  advantages:  as l o g i c a l  to  from  complex arenot  as  Simulation  (Phillips [44]).  High  [44]) were  (Mellichamp  are  t o determine  how  i n i t s structure by w h i c h  system  and mathematical  simulation  GASP.  facility  experiments  and parameters.  purpose  SLAM,  (Halpin  distribution  following  general  either  procedure  variables  SIMSCRIPT,  construction  numerous  I t i s a  input  a r e many  projects  i n order  t o changes  and analyzed  of system  other  trades  f o r t h e more  i n which  of a system  i n i t s environment.  outputs  and  SIMULATION  procedure  on t h e m o d e l  and  of the  c a n be o b t a i n e d  However, m a t h e m a t i c a l  EVENT  time  the crane  tables.  i n large  idle  languages,  level  languages  developed  especially  has been  applied  design  and  production  [84]), material  [102]),  In general,  to  and simulation  handling high-rise has t h e  43  1.  It  allows  order  managers  to  Decision  elements of  3.  real  i n the  factors  in are  all  during  foreseeable  the process  of  model. makers  without  to  the  construction  simulation  operations  the  curve  arise  to examine  decision  construction  other  system  experiment  risk  of  with  disturbing  system.  that  learning  the  external  in d e t a i l  strategies  Many authors recommend  forced  model  allows  different  with  they i n t e r a c t .  are  the  which  a simulation  Simulation  the  how  makers  designing  experiment  determine  important and 2.  to  stochastic  should  because  effects, project  i n the complex and  management be  used  other  models  come-back  delays,  variables  and  literature to  model  cannot  treat  weather,  parameters  exposed environment of  and  which  construction  projects. Simulation to  simulate  studied  and  can  which  has  be  of  other  using  they  requires  most  by  developed  i s a powerful t o o l that can be used the  modeling  the  applied  complex  technigues.  techniques only  represent.  to  Use  the of  are  the  the  use  and  cannot  be  models  "custom-made"  project  simulation  situations  technique  also  language. Mathewson  [79]  of a " ( s i m u l a t i o n )  to reduce the programming e f f o r t  that  However,  generally  specific  knowledge of a s i m u l a t i o n  suggested  research  situations  reliably  program  required;  development i n t h i s area  are  generator"  however, f u r t h e r required.  44  4.2.4  MONTE CARLO Monte  values and  method  f o r random  combined  study.  i s a  variables  t o determine  I t c a n be  activity a  Carlo  SIMULATION  possible  value  from  outcomes  durations  are  treated  as  path  calculations  repeated  many  times,  project  duration  provide  unbiased  an  each  activity.  of  profile  activities,  an  often  distribution  provided a  estimate  results  large  the  the  normal  The p r o c e d u r e i s on each  projected  times of  individual  the  of the project  simulation completion-  of the " c r i t i c a l i t i e s "  i s made  a  priori  on t h e  a  reliable  d i s t r i b u t i o n i s dominated  by a few  are not correlated.  number of  of simulations  the  requires  there  represents  generated, and  of  indication  activities  and thus  t h e number  The  f o r each  that  Once  under  calculating  d i s t r i b u t i o n . I t provides  projection  In addition,  number  assumption  i fthe f i n a l  requires  accurate  time.  No  the final  even  by randomly  statistics  projection  d i s t r i b u t i o n and an  shape  it  critical.  distributions  durations  a r e performed.  the  whereby  t h e system  deterministic  keeping  and  were  of  t o generate  f o r the activity.  activities  from  the distribution  critical  of  properties  utilized  technique  a r e sampled  i n a p r o b a b i l i s t i c network  feasible  time  simulation  profile  large  i s no  of simulations  measure  t o produce  of  amounts  the  of  by w h i c h  required.  However,  final  computing one c a n  45  4.2.5  PROGRAM EVALUATION AND REVIEW TECHNIQUE The  major  assumption The  difference  between  PERT  and  CPM  i s the  of d i s t r i b u t i o n s f o r a c t i v i t y d u r a t i o n s f o r PERT.  o r i g i n a l developers of PERT chose a beta d i s t r i b u t i o n to  estimate Given  the shape  of the a c t i v i t y  the most l i k e l y ( m ) ,  estimates  of an  duration  optimistic(a),  activity  duration  distribution.  and p e s s i m i s t i c ( b )  the mean  and  standard  d e v i a t i o n of the a c t i v i t y d u r a t i o n are approximated  The  mean  =  (b - a) / 6  standard dev.  =  (a + 4m + b) / 6  developers  distribution  was  PERT for  proved  actually restrict After  of  chosen  [33]  Elmaghraby  the  (PERT)  The  project limit  the estimated that  duration w i l l theorem",  approximation  the  above  activity  and  is  the tends then  ignoring  durations  of the p r o j e c t  activity  beta  However,  function.  are estimated, i s computed  by  d u r a t i o n s as d e t e r m i n i s t i c .  resulting  distribution  of the  normal, because of the " c e n t r a l made. the  In  making  correlations  paths, the r e s u l t i n g estimates on expected become o p t i m i s t i c ,  the  approximations  the shape of the d i s t r i b u t i o n  the expected  assumption  that  its flexibility.  that  mean-time-to-completion  treating  claimed  by:  i . e . underestimated.  the of  above network  project durations  46 4.2.6  DECISION Decision  by  having  CPM  CPM  both  networks  (Naaman  deterministic  nodes. The d e c i s i o n s  taken  [90]) are c h a r a c t e r i z e d  activity  nodes  and  decision  at the d e c i s i o n nodes depend on  the outcomes of events which are not known with  certainty in  advance. Completion of the network can be achieved number  of p o s s i b l e  optimal  determined by a lengthy acceptable  path  can  paths.  The optimal  i n t e g e r programming be  determined  by  through a  path  can be  procedure or an more  economical  i n t e r a c t i v e h e u r i s t i c procedures. T h i s model forms the b a s i s of more complex ones, such as GERT d i s c u s s e d  4.2.7  GRAPHICAL EVALUATION AND REVIEW  below.  TECHNIQUE  (GERT) GERT, developed  Graphical by P r i t s k e r  [105]),  represents  network  modeling  representation types.  Evaluation and Happ  and s i m u l a t i o n  The s p e c i a l f e a t u r e s  activity  time  extension It  makes  of l e s s  of GERT  distributions,  Review  Technique,  ( P r i t s k e r and Happ  a considerable technique.  and  to the PERT/CPM possible  restrictive  include  user  probabilistic  with of  logics;  definable branching, complex  t h e r e f o r e complex models of systems  random v a r i a b l e components the model  the  network  m u l t i p l e outcomes, feedback, s e l f - l o o p i n g , and other node r e a l i z a t i o n  [104],  i s performed  can be r e p l i c a t e d . Execution  by Monte  Carlo  type  simulation  47  procedures.  Model  optimizing  and  and  Because  error.  with  GERT,  develop  4.2.8  system  the  and  outputs  descriptive  improvements  of  the  model  of  are  given  from  idea  for  administration deadlines.  slack  of  In  PLANET  assumption  not  an of  meet  them  modeling  logic  is  difficult  can  under  to  not  be  developed nine  version  critical  path.  which  i t is  critical  from  the  or  slack  a viable the  t e c h n i q u e as  critical  path  completion for activity  the  tends  time.  The  duration  in  the  to  g e n e r a l enough. by  Pritsker  probability of  GERT  Kennedy  uses  promised  funds,  are  in  ones.  mean  distribution  arose  NASA  t o meet  "stolen"  variances over  beta  by  limited  which  be  [62])  faced  Program  activities  optimistic  a  may  from  modified  trial  Thrall  problems  c o n s i d e r e d t o be  and  original  PLANET  to  resources  mean  produce  choose  by  EVALUATION  and  to expedite the c r i t i c a l  of  GERT  the  determine  PERT was  PERT a l s o  (Kennedy  the Space S h u t t l e  that  activities  of  order  to  such  summing  than  (PLANET)  consideration  essential  the  system  PROJECT LENGTH ANALYSIS AND  The  performed  c o m p l e x i t y of a  rather  understand.  TECHNIQUE  to  are  the  GERT m o d e l i n g  did  and  Happ  allows  distributions. not  and  Thrall  Monte  Carlo  include [62]  technique with  However,  analysis  therefore  simulation critical  user  of  the  developed  approach path  the  to  a  analysis  48 at  each  simulation  the i n c l u s i o n type  and  thus  allows  feedback,  looping,  and  of l a r g e v a r i a n c e s i n the development/testing  activities.  4.2.9  PROBABILISTIC  NETWORKING  EVALUATION  TECHNIQUE  (PNET)  PERT c o n s i d e r s a c t i v i t y  d u r a t i o n s as random  However, the r e q u i r e d p r o j e c t  d u r a t i o n i s determined  on the b a s i s of the mean c r i t i c a l expected  completion  time  path and  for  a  problem  but  i t requires  solely  subsequently  given  underestimated. Monte C a r l o s i m u l a t i o n the  variables.  network  can be used  and  is  to s o l v e  c o n s i d e r a b l e computing  These are the o b s e r v a t i o n s that motivated Ang  the  time.  Abdelnour  [4] to develop PNET. The between  technique different  activities  which  Abdelnour  [4]  employed paths  or  100%  selecting  has  that  the paths are d i f f i c u l t 0%  which  PERT  stated  considers arise  probabilities analytical,  then of  the  sharing  ignored.  Ang  of and  correlating  to c a l c u l a t e except f o r the cases of  correlation.  can  correlations  probabilities  They  then  r e p r e s e n t a t i v e paths. The  probability  from  previously joint  the  be  these  calculated paths.  i t i s be more economical  Monte C a r l o s i m u l a t i o n technique.  proposed project as As  the the  a  scheme  for  completion-time product  of  the  technique  is  and e f f i c i e n t  than  the  49 4.3  MATHEMATICAL  PROGRAMMING  TECHNIQUES  In a d d i t i o n to the modeling techniques d e s c r i b e d other  mathematical  models  have  been  described  above, i n the  o p e r a t i o n s research l i t e r a t u r e . Of these, l i n e a r programming and  dynamic  programming  have  been  applied  to c o n s t r u c t i o n  problems. Most  applications  techniques  described  engineering optimal  of  i n the c o n s t r u c t i o n  literature  have  resource a l l o c a t i o n s  duration  compression  development industrial described  work  (Perera  has  also  engineering. by  mathematical  Riggs  been  programming and  applied  (Coskunoglu  industrial  to problem  of  [24]) and network  [100]). E x t e n s i v e research and been  The  done  in  "Economic  [110] and  the  the area  Scheduling "Multiple  S h o r t e s t Path Problem" d e s c r i b e d by White  of  Path"  Objective  [130] are based on  these mathematical programming t e c h n i q u e s . Even  though  mathematical  programming  an optimal s o l u t i o n  to be i d e n t i f i e d  alternatives,  have  they  construction related (1)  constraints  mathematical (2)  The  effort,  situation  from a l a r g e number of  the f o l l o w i n g  disadvantages f o r  problems:  In most s i t u a t i o n s , and  techniques allow  the p r o j e c t cannot  be  objectives, easily  variables,  reduced  to  form. cost, into  and  time  mathematical  to  reduce  equations  a are  problem often  50  excessive  (3)  f o r use  i n c o n s t r u c t i o n planning  day  basis.  The  time r e q u i r e d  too  long.  The  on a day-to-  to modify a developed model i s o f t e n  mode i s t h e r e f o r e  not  responsive  dynamic p r o j e c t c o n d i t i o n s at the p r o d u c t i o n (4)  The  models  developed  with  this  CURRENT  PRACTICE  Deterministic acceptance  in  simplicity.  Among  critical be  techniques  projects  for  are  and  has  the  critical  of  detail  i s the  briefly  The  which i t has  planning been  major a c t i v i t i e s , a c t i v i t y estimates  are  activity  then can  be  defined  is  to at  is f i r s t  to each as:  can  that  construction the  critical  i s shown i n f i g u r e  d u r a t i o n and  assigned  model  be the  on  the  level  carried  out,  activity  level,  activity. broken down i n t o resource  activity.  form  4.6  Although  4 . 1 . 2 .  restriction  applied  c o n s t r u c t i o n process  the  of  in section no  relative  described,  of  application  path method p l a c e s at  models  analysis  described  gained  their  analytical  planning  level.  have  of  the s m a l l e s t element t r e a t e d i s an The  an  only time  in c o n s t r u c t i o n  been  because  deterministic  activities.  traditionally, i.e.  the  not  MODELING  techniques  construction  systematic  and  path method  CONSTRUCTION  modeling  path method  used  IN  the  levels.  comprehensible to management at the p r o d u c t i o n  4.4  to  and  pour  the  requirement For  example,  a  complete  51 floor  slab in five  days employing 5 c a r p e n t e r s , 4 masons, 2  general  labourers  and  implicit  management  the  tower  crane.  out  input  data  the  operations  are  then  [131]  .. . . have  leveling  reviewed  resource focused  d u r a t i o n as fixed  the  activity limits  practical  need  resource  CPM  activity.  and  and  in  scheduling quality  using  project  They have assumed fixed  time."  There  flexibility  constraints  resource  is  i n the  and  resource  algorithms  the a c t i v i t y d u r a t i o n s and  for  The  stated that:  criterion.  over  to  constrained  developments  duration,  over  resource of  algorithm  the only  each  the  algorithms.  constrained  on  requirements  process,  crew assignments  in  using  c o n s t r a i n e d s c h e d u l i n g algorithms 11  and  involved  analyzed  resource a n a l y s i s and Willis  the  d e c i s i o n s have been made r e g a r d i n g  c h o i c e of c o n s t r u c t i o n t e c h n o l o g i e s carry  In  fixed  ....  "the  definition  requirements  ...."  [131] Willis of  further  a system  described  f o r a n a l y s i s of  the  "practical  resource  requirements"  constrained p r o j e c t s .  They i n c l u d e : (1)  stability project  in  such  the o r i g i n a l (2)  re-scheduling that  there w i l l  v a r i a b l e resource  facility  be  a  resource no  constrained  drastic  changes  to  schedule; requirements  resource c o n s t r a i n t s over (3)  of  over  time  and  variable  time;  to allow an a c t i v i t y  to be f i x e d  i n time;  52 (4)  facility  to  allow  stretching  and  squashing  of  act i vi t i e s ; (5)  facility  to  allow  consideration  of  variable  requirements over the d u r a t i o n of an a c t i v i t y ; (6)  facility The  requirements  approach failed the  to allow assignment of a l t e r n a t i v e  to  simply  construction  indicate  process  that  modeling  resource and  resources. the  using  current CPM  has  to model a l l of the p r a c t i c a l or r e a l i s t i c aspects  construction  assumes  planning  constant  process.  resource  The  requirement  current over  of  approach  an  activity  d u r a t i o n such that i n the example used e a r l i e r , the  assigned  labour  assigned  resources  "exclusively" This are  the  required  clean  the  and  activity three  for  scheduling and  They do be  not  part  of  labourers  formwork  each  methods a  of  crane  at  have  form and  the  second allow  modified  day. neglect shift  activity  the  to  the  be  In  floor  slab.  resources  duration.  and  end  For  only  to  of  the  needed only f o r about constrained  possibility  durations  be  required  start  eliminate  interactively.  pour  activity  might  Current  to  the assigned  the tower crane might be  hours  time  only  o i l the  tower  because some of  general  and  the  activity  is un-realistic  example,  to  to  and  of  resource  and other  assigned words,  resource using  over  conflicts. resources the  need  e x i s t s f o r a more " f l e x i b l e " framework to t r e a t the elements that  the  capture.  current  approach  to c o n s t r u c t i o n modeling f a i l s  to  53  In  addition,  decision  choice  of construction  which  are  only  making  processes,  technologies  implicit  in  the  and crew current  construction planning, must be treated.  such  as the  assignments, approach  to  ^  START  ^  L i s t of A c t i v i t i e s ) and P - r e l a t l o n s /  Activity Durations  Z  7  Set Resource  /  1/ C r i t i c a l Path Ana l y s i s  P r o j e c t Duration Activity Start/ F i n i s h Dates  <^ #, > I m p l i c i t Management D e c i s i o n s #  1. Choice of t e c h n o l o g i e s and c o n s t r u c t i o n methods 2 . Resource a l l o c a t i o n and crew assignments  Resource Analys I s  rES  \1 Constrained Resource AssIgnment  1  Pro} e c t Schedule To S i t e Management^  ^  Figure  4.6:  STOP  Current application of CPM in construction  0  ^  planning  A  55  5.  PRODUCTION  Russell is  the  [114] has s t a t e d :  characterized  repetitive best  by a  activities,  from  projects  [7] s t a t e d  processes  i n their  repeating  sequence."  balancing  problem  large  repetitive  assembly  line  design  The  among  break  down."  of a  small  with  and  by  The  operations above  and  between  the  t h e assembly  studied  and  industrial  line  suggested  engineers  c a n be a p p l i e d  i n  assembly-line  similarities  have  problems  "The  line  tasks  repetitive  problem  used  s e t of  products."  the  few  assembly  to the  for design  repetitive activities. In  and  despite  similarity  resemble  identical  However,  approach  ....  activity  [31] s t a t e d :  design  the  duration  "Multiple-unit, multiple-floor, or  noted  whether  of  and  i s concerned  activity  problem.  systems  Davis  have  of r e p e t i t i v e and non-  i s substantial  projects  of  construction  and a r c h i t e c t s t o d i s t i n g u i s h one  structure  numbers  authors  design  of short  that:  progressive  other  each  of  linearly  and  number  another, there  i n terms  building  large  e f f o r t s by owners  project  Ashley  PLANNING AND ASSEMBLY LINE BALANCING  this  the line  chapter, balancing  similarities  construction determine applied  the assembly problem  and  assembly  to construction  production line  cycle  production  are studied  differences  and assembly  whether  line  between will  balancing  planning.  i n some  be  process detail.  repetitive analyzed  techniques  to  c a n be  56  5.1  PRODUCTION Many  as  of the planning  bar chart  field  PLANNING  tools,  i s a  which  operate change.  planning  word  could  on  that  for  the environment managers  planning,  execution,  production  process  operations  are  and to  of  have  their  origin  themanufacturing materials  to  bring  about  a r e faced control  with  of  that  changed  the  by  used t o  goal-oriented  operations  on  in  the problems of  the  quantity,  such  industry.  as c o n t r o l l e d forces  ensure  agreed  i n construction,  describes  be d e s c r i b e d  Production  specific  used  and l i n e - o f - b a l a n c e ,  of production  Production  models  i n the  results  of the  schedule  and of  q u a l i t y and c o s t .  Schmenner  [117]c l a s s i f i e d  the production  processes  as  follows: (1)  J o b Shop  -  shop  produces  that  assembled (2)  Batch  products  e.g.  lots a  which  materials, (3)  -  have  models,  of products  e.g.  a  food  food  i s served  with  no o n i o n  parts  generally  factory  t o meet  which a r e  orders  that  designed  in-  manufactures  of a wide  v a r i e t y of  and s i z e s .  Assembly  but with fast  or plastic  e.g. a machine  machines.  clothes  Worker-Paced products  custom products;  metal  into other  Flow  house;  generally  Line  opportunities restaurant  but certain  -  mostly  f o r selected  where options,  a  standard such  or pickles, are possible.  standard options; list  of  as hamburger  57 (4)  Machine-Paced in  as  intensive; conveyor paced  assembly  tasks  rationally group  LINE  possible; have  a  i s more  labour  line,  products.  or  a  Machine-  referred  products usually t o be  paper  with  t o as  not  little  produced  measured  mill  productivity  or  in  i n tons,  a  petroleum  i s only  and  or  dependent  the capacities  of  PRODUCTION  (1863-1947)  i s usually  "assembly  line  further  t h e components  idea  of t h e end product and so  on  component  i s reversed, ( t h eb a s i c  credited  e r a " when  i n t r o d u c e d . The b a s i c  indivisible  be  on t h e  simply  raw m a t e r i a l s  sub-subassemblies,  subdivision  standard  where  i s decomposition  smallest  dependent  production  are often  and so  of  the  was  mix as  equipment.  Ford  automobile  work  -  plant  ASSEMBLY  of  product  (3) w h i c h  of electronic  e t c ; e.g.  processing  and  Flow  t h e type  creation  same  i s more  automobile  lines  units  processing  line  -  lines".  barrels,  Henry  to  line  customization  discrete  5.2  a  assembly  Continuous  on  compared  e.g.  "assembly  no  Line  (3) b u t t h e p r o d u c t i v i t y  equipment  (5)  Assembly  we  subdivided) into  the  of the  into  the first  assembly  subassemblies,  down  the line  until  the  i s  reached.  If  this  can define  indivisible  with  unit  the operations or  o f work  which  subassemblies,  that  cannot  are necessary and so on,  to  until  58 the this  end  product  process  i s reached.  i t i s known  Because as  the  of the l i n e a r  assembly  line  aspect  of  production  process.  5.2.1  LINE BALANCING PROCEDURE Balancing  following (1)  an a s s e m b l y  number  The  in  normally  involves  the  of s t e p s :  industrial  done  line  engineer  detail,  must  including  describe the  what  has  descriptions  to  be  of  job  which  is  elements. (2)  Each  of  often or (3)  job elements  determined  by s p e c i a l  Once  times  engineer  (4)  the  by  reference  stopwatch  are  them  production  are  r e a s o n a b l e . Changes  used  to  this  i s done  and  balance  placing  to  with  the  agreement  line  to  i s by  the  standard  the  loads  another.  the  s u p e r v i s o r s on  whether  or  not  they  reguired.  relevant  among  work  job elements,  relevant  a r e made a s  taking  them w i t h  time  established  specific  determine  i s reached, work  to  a  studies.  assigned  reviews  Once  i s assigned  information i s  the workers.  elements  from  one  One  way  worker  59 (5) The  initial  balance  adjustments  are  i s s t u d i e d f o r reasonableness  made u n t i l  the  line  is  and  satisfactorily  balanced. (6) The  "paper"  factory all  floor.  are  larger  the worker work  changing  The  pieces  product  and  bottlenecks  ready  for  trial  s u p e r v i s o r s , and  activity.  If a c t u a l  p r e d i c t e d , help w i l l be time  adding  - by  changing  fixtures  or  the  other  on  the  workers element given to  layout of equipment,  p r o d u c t i o n methods, or reducing the t o t a l work  keys  p i e c e s and  than  to improve  by r e - b a l a n c i n g the assembly  EXAMPLE OF  complex  then  engineer,  station,  assignment  5.2.2  The  is  become i n v o l v e d i n t h i s  times  the  balance  LINE BALANCE  to  line  and  tasks and tasks are  line.  balance  production  are  process  (2) j u g g l i n g  so  that  the  built  into  i t . An  assembly p r o d u c t i o n process  (1)  breaking  into  down  i t s component  the c o o r d i n a t i o n of  process  is  example  smooth of  i s shown i s f i g u r e  a  a  these  and  no  20-element  5.1.  F i g u r e 5.1(a):  network of work elements  JOB ELEMENT  ESTIMATED TIME (minutes)  JOB ELEMENT  ESTIMATED TIME (minutes)  1 2 3 4 5 6 7 8 9 10  0.65 0.11 0.37 0.75 0.10 0.58 0.25 1.01 1.17 0.43  11 12 13 14 15 16 17 18 19 20  1.10 1.75 0.94 0.62 0.45 0.81 0.87 1.60 0.60 0.83  F i g u r e 5.1(b):  Figure  Precedence  5.1:  Job elements  and estimated element  Example of a 20-element  assembly p r o d u c t i o n  process Source:  times  Schmenner [117], p. 97  61  The  objective  i s to  use  the  information  given  to  develop a flow l i n e process capable of t u r n i n g out 300 u n i t s of  the product i n an e i g h t hour day. The suggested p o s s i b l e  means of developing the process can be summarized Total  as f o l l o w :  job element time = Sum =  (element time a l l elements 1 to 20)  14.99 minutes  T o t a l p r o d u c t i o n minutes req'd / working day =  14.99 min/unit x 300 u n i t s  =  4497 minutes  Assume a 7.5 hour work day (450 min) Number of workers req'd/ working day =  4497 min. / (450 min./worker)  =  10 workers  For p e r f e c t balance: " C o n t r o l c y c l e time"  The  =  (14.99 m i n u t e s / u n i t ) / 10 worker  =  1.5 minutes  following  b a l a n c i n g problem:  i s a suggested s o l u t i o n  to the assembly  62  WORK STATION  JOB ELEMENTS  TOTAL TIME/UNIT (minutes)  1 2 3 4 5 6 7 8 9 10 11  1,2,4 3,5,6,7 8,10 9,12 9,12 13,14 11 15,17 16.18 16.18 19.20  1.51 1.30 1.44 1.46 1.46 1.56 1.10 1.32 1.21 1.21 1.43  Fig.  5-2:  Suggested  -0.01 0.20 0.06 0.04 0.04 -0.06 0.40 0.18 0.29 0.29 0.07  balance to the assembly  production Source:  BALANCE DELAY (minutes)  line  process  Schmenner [117], p. 98  Observations p e r t a i n i n g to t h i s s o l u t i o n a r e : Eleven  work  because  of  stations  are  the i n a b i l i t y  reguired  to meet  instead  of  the i d e a l  ten  "perfect  balance. " Some s t a t i o n s  have been  are u n d e r - u t i l i z e d Stations other  are  i n order  (note that  1.75  resulting  while  some  and  control cycle  to s o l v e  the times  1.60  station,  i n unproductive i d l e  4, 5, 9 and 10 have workers working  unit  cycle"  overloaded  the problem  of job elements  respectively  which  are  time.  on every of  "over-  12 and 18 over  the  time. I f only one worker was assigned to  work on element 12 or 18, b o t t l e n e c k s would occur.  63 5.3  ASSEMBLY LINE BALANCING ALGORITHMS In  general,  the  objectives  in designing  an  assembly  l i n e process are to minimize the number of groupings or work s t a t i o n s with a given time  for  a  restrictive Two  given  number  time, or to minimize the c y c l e  of  stations  subject  to  certain  balancing  problem  constraints.  approaches  have been  cycle  adopted  to the assembly by  line  manufacturing p r o d u c t i o n  the a n a l y t i c a l approach  management -  (Akagi [ 3 ] , Wilson [132]) which  an " o p t i m a l " s o l u t i o n and the h e u r i s t i c approach Raouf  et a l [109], Tonge 126])  solution.  The  programming  analytical  technique  which  gives  approach  which  most  routines  that  approach  reduce  the  authors  manageable by manual or computer are  used  beings  to simulate  when  they  of  a  "acceptable"  to  problem  of  selective  until  i t is  operations. Sensible  unaided  in  the  be  effort.  the decision-making p a t t e r n  operate  integer  agree  i s the a p p l i c a t i o n size  (Arcus [ 5 ] ,  employs  demanding i n terms of mathematical modeling The h e u r i s t i c  an  give  rules  of human  system.  Another  reason f o r the use of h e u r i s t i c s f o r the ALB problem i s that the  number  of  possible  groupings  of  work  elements  i s so  l a r g e that an e x h a u s t i v e enumeration scheme i s u n - r e a l i s t i c .  64 5.3.1  SYSTEM  Similar production  to  line  technological performed may  CONSTRAINTS a  construction  i s also  constraints,  i na specific  arise  equipment  subjected  because  process, to certain  i . e . t h e work  order.  assembly  precedence  tasks  have  or  t o be  I n a d d i t i o n , zone c o n s t r a i n t s  of the physical  or the operator,  an  location  or because  of  specialized  of health  or safety  regulations.  5.3.2  PRIORITIES  Tonge to  assist  OF WORK ELEMENT  [126] g i v e s  a list  ASSIGNMENT  of the rules  i n t h e assignment  of  work  that  c a n be u s e d  elements  to  work  stations: (1)  Choose  the task  (2)  Choose  the task  This  with  increases  assignment  the largest  with the  t h e most number  t o the next  (3)  Choose  a task  (4)  Choose  the  of  time. "immediate" tasks  followers.  available for  station.  randomly. task  which  task  which  became  available  first  f o r  available  last  f o r  followers  (including  ass ignment. (5)  Choose  the  became  assignment. (6)  Choose  the task  followers  with  t h e most  t o i t s immediate  followers).  This  rule  also  65 i n c r e a s e s the number of tasks a v a i l a b l e to the next (7)  station.  Choose the task f o r which the sum of i t s times p l u s the times  (8)  of  it's f o l l o w e r s  i s the l a r g e s t  (Helgeson  and  Birnie  [48] c a l l e d t h i s the ranked p o s i t i o n a l w e i g h t ) .  Number  the tasks such that a l l f o l l o w e r s of a task have  a  higher  number,  necessary.  a s s i g n i n g a number  Choose  the  task  with  Number  a l l tasks  with  no  arbitrarily  the  ( f o l l o w i n g a s u g g e s t i o n of Jackson (9)  f o r assignment  lowest  when number  [53]).  predecessors  as  1.  I f the  highest number assigned to any immediate predecessor of a task  i s n, number  task with  that  the lowest  task  number  K i l b r i d g e and Wester  [63]).  Numerous  rules  assignment  n + 1. Then choose the  (based  were  on the approach  also  recommended  other authors; Raouf et a l [109] suggested  giving  to work elements  path.  5.3.3  BALANCED ASSIGNMENT AND Another  work  problem  assignment  another  station  delay".  This  (proportional each  which are on the c r i t i c a l  work  that  no  may  have  an  measured  to the sum  station)  by  priorities  SMOOTHING  o f t e n d i s c u s s e d i s that of a "balanced"  such  is  of  station  i s overworked  excessive by  the  of the squares  as d i s c u s s e d  amount  of  smoothness of i d l e  i n Moodie  while "idle index  delays at  and Young [88].  66  The  smoothness  transfer"  5.3.4  o f work  elements  VARIABLE  ELEMENT  The  problem  recognized an  scheme also  discussed  work  worker  production  and Young work  element  times  element  Later,  times  incentive  Mansoor  [74]  of the selection  of N  available to  by  "confidence  t h e u s e o f a wage  ratings  were  [88] d e s c r i b e d  a user selected  i n terms  of M  times  o f work  productivity.  the problem  performance  element  and v a r i a n c e s  out of a pool  their  stations.  variable  [77] d i s c u s s e d  t o ensure  5.3.5  variable  balanced against  Mansoor  by " t r a d i n g and  TIMES  consider  the averages  operators to  to  the problem  level".  of  between  b y some a u t h o r s . M o o d i e  algorithm  including and  o f a b a l a n c e c a n be i m p r o v e d  operators  just  meet  according  the  desired  level.  ELEMENT  SHARING, M U L T I P L E  MANNING  AND  MULTIPLE  STATIONS Some a u t h o r s use  of  multiple  balancing  i s less  problem  manning  to solve  realistically time  (Arcus  in  of  a  the problem  be b r o k e n than  [ 5 ] , Akagi et a l [3])  down  the cycle  t h e manner  work  station  when  a  further  work  such  discussed the  or  "parallel"  element  that  cannot  t h e element  time. Akagi et e l formulated the  that  a  worker  can  move  between  67 stations  i n order  to a s s i s t  another  when the work at h i s s t a t i o n Sarker  et a l  [116]  worker with  i s complete  formulated  an  element  (element s h a r i n g ) .  the problem to allow  parallel  work s t a t i o n s to i n c r e a s e e f f i c i e n c y and p r o d u c t i v i t y and reduce c y c l e time below the g r e a t e s t element  5.3.6  to  time.  RELATED A C T I V I T I E S Arcus  problem  [5], i n h i s d e s c r i p t i o n of COMSOAL, t r e a t e d  by  proposing  to a s s i g n  the  work elements  the  according  to f i v e programs: 1.  use no  2.  group tasks by workers p o s i t i o n ,  3.  group task by  4.  group tasks by u n i t ' s p o s i t i o n , or  5.  any This  early  as  criterion,  tools,  combination problem, 1960  and  of the above in f a c t , later  was  criteria. studied  discussed  by  by  Tonge  Agrawal  [126]  [1]. Agrawal  stated that: "An  assembly  related  to  others.  The  belonging on one  some  may  to  the  be  operations  relationship  another  allotting (or  operation  can  considered and  be  by  same subassembly,  .... The  to  unrelated ways of  be to  their  interdependent  a l g o r i t h m employed w i l l  be  a set of r e l a t e d o p e r a t i o n s to a worker  workers)  as  against  operation allotment  the "  usual [1]  as  operation-by-  68 The  "relatedness"  determined algorithm less  a  set  the precedence forms  feasible  the  given  cycle  from  of  links.  which  than  starting are  by  of  (total of  is  proposed  an  given  operation  related  the end of the precedence  then assigned with p r i o r i t y  elements  Agrawal  sets  time)  work  time  operations  network;  the s e t s  to the s e t s with the  l a r g e s t t o t a l times. Tonge related  [126] e x p l o i t e d  the work  employed  an  the s t r u c t u r e  elements  hierarchical  into  "sets"  approach  of a network and and  "chains"  to the task  and  assignment  problem. In phase one of h i s approach, men are a s s i g n e d to a group of work elements work  element  element  to work  time  available  instead  typical  station  i n any grouping  of the t y p i c a l or men;  thus  i s limited  by  of the " a v a i l a b l e s t a t i o n  two of h i s approach, the  instead  procedure  the assignment of a s s i g n i n g  assignment of  the t o t a l the t o t a l  men  time". In phase  procedure then work  work  elements  follows to each  i n d i v i d u a l s t a t i o n or man.  5.3.7  OTHER  The  CONSIDERATIONS  following  concepts were a l s o d i s c u s s e d  by M a r i o t t e  [78] : Batching  and banking  using  an  time f o r a s h o r t p e r i o d of time.  extra-shift  or over-  69  Multiple  Lines  production  rate.  Off-line  stations  certain joined  5.4  work with  or  multiple  and  elements  LINE  to  subassembly  a r e performed  t h emajor  ASSEMBLY  shifts  increase  lines  before  where  they  are  assembly.  BALANCING AND  CONSTRUCTION  CYCLE  DESIGN  5.4.1  SIMILARITIES  BETWEEN  A L B AND  CONSTRUCTION  CYCLE  DESIGN The  two p l a n n i n g  processes large also  consist  number  functions  of sets  of s i m i l a r  resemble  each  other  resemble  of repetitive  or identical i n that  each  i n that  tasks  finished  both  t o produce products.  t h e managers  a  They  a r e concerned  with: (1)  formulation out  of operations  t o produce  and works  the finished  tasks  products  t o be c a r r i e d  within  project  constraints; (2)  choice of  of technologies,  work  site  efficient (3)  balanced work  to carry  and e f f e c t i v e assignment  tasks  t o work  choice  of equipment,  out the operations  and l a y o u t i n t h e most  manner;  of the identified s t a t i o n s or workers;  operations  and  70  (4)  implementation operations  (5)  of a production  a t t h e work  devising  production  productivity,  lower  time  unit.  5.4.2  f o reach  DIFFERENCES  plan  and monitoring  of  s i t e ; and  method  improvements  production  BETWEEN  cost,  A L B AND  to  increase  and reduce  CONSTRUCTION  cycle  CYCLE  DESIGN Bolinq as  [12] d e s c r i b e d  sequential  crew  repetitive construction  systems  and s t a t e d  that  projects  a sequential  crew  system: "consists  of  another  i n  particular in  these  immobile  a  task  or  constructed. and  a  Units  relatively  processed  by  typical  system,  the first  crew  brings  these  units  as  they  perform  their  assigned  enter  Bolinq  complete  and t h e remaining  with  processed  they  one  systems into  sequence are  to  large  t o those  following  t h e system  process Crews  being  are often  as compared  units  crews  sequence  on a u n i t  the sequential  new  more  fixed  systems  production In  two  assembly  production  i n a  t o one a n o t h e r ,  by each  crew  has given  a  work  available.  respect  t h e system."  between  become  repetitive  a  fixed  and u n i t s  i n t h e same  order  as  [12]  good  summary  construction  line  crews  but stopped  of  project short  the and  differences a  typical  of suggesting  an  71 algorithm  for  the  between the two (1)  Units  systems can  in construction  worker  have  construction (2)  Unit  construction  to  context.  be summarized as projects  travel  are  follows:  the  workface  u n i t s can be  as  number is  considered  i n t o the system when work by  crew i s i n i t i a t e d . In-process inventory  assembly  immobile;  progresses.  introduced  small  differences  l a r g e and  along  in r e p e t i t i v e construction  to be  The  of  units;  buffer  non-existent  first  is limited  stock  i n most  the  of  projects.  to a  the  main  This  make  the proper balance of crew assignments more c r i t i c a l avoid unnecessary i n t e r r u p t i o n and (3)  Factory  type  numbers  of  time;  assembly smaller  feedback  on  line  items the  idle  time.  production for  an  produces  extended  effectiveness  to  of  the  large  period  of  production  process can be c o l l e c t e d more q u i c k l y and  modifications  for  improvement  more  and  easily.  can  be  improvements  in  p r o d u c t i v i t y . In c o n s t r u c t i o n p r o j e c t s , there might  not  be  sufficient  to  the  pay  production  and,  construction  back  in  design  once  requires  on  future  time to study and  implemented. This design  expended  quickly of  will  effort  implemented  improvement  balance  Any  also  implement the  improvements  initial  optimization  of  design the  where p o s s i b l e , c e r t a i n f l e x i b i l i t y process  accommodate changes or  should  be  improvements.  is  initial in  maintained  the to  72 (4)  Because of  of  the  s i z e of  workers  Assignment  lowers  of  work  consideration  the  relocation  of  Relatedness  the  productivity  elements  from  however,  has  so one  relocation  significantly.  therefore  relatedness  workers  i s ,  u n i t , unnecessary  to  as  to  area  difficult  take  reduce  to  to  into  another.  be  clearly  def i ned. (5)  The  work  elements  restricted  by  equipment,  and  imposes  of  construction  requirements limited  additional  projects  for  space  special  at  constraints  are  the on  trades  work  the  often  face.  work  or These  assignment  process. (6)  In  construction  unit  (7)  (8)  being  projects,  produced,  rather  than  the  broken  down  into  the  the  large  Because  of  processing  can  be  achieved  The  way  the  unit  less  well  of  construction an  of  can  be  of  an  size is  work  operations,  defined)  cycle  in is  design  program  is  of  the  the norm  operations  unit  produced  experience  interactive  the  d e t a i l s of  size  the  manning  unless  finer  time  of  are  tasks. and  thus  element  more e a s i l y i n c o n s t r u c t i o n  the  input  multiple  exception  longer  rather  because  the  sharing  projects.  more  flexible  (or  construction  projects  and  therefore  process. which  desirable  This  may  prompts  in  the  necessitate  the  user  for  d e c i s i ons. (9)  Because  of  construction  the  complexity  operations  as  and  skill  compared  to  dependence the  more  of  routine  73 motions are  f o r an  more  susceptible  element  times  maintain.  responsive  Because  of  manufacturing  better and  line  of  of of  trades  cycles work  operations,  heavy t h e more  more d y n a m i c p r o j e c t  cycle  of  because  flexible  to  assembly projects  might  however  than  in  operators  perform  the  find  Design  the  of t h e p h y s i c a l  construction  environment.  to analysis  problem.  level  units  of s k i l l e d  equipment  manufacturing  techniques  constraints  assembly  larger  planning  between  design  the  developing  construction  balancing  line  of of  approaches  at the production  the requirements  and  defined  repetitive  and  DESIGN  put into  The s i m i l a r i t i e s  production  immobility  CYCLE  f o r production  well  assignment  manipulate  availability  systematic  line  construction  environment  has been  to the construction  an assembly  projects,  more  assembly  stringent  and  the  effort  Relatively  construction  more  and  and  to  to  site.  stable  and computer programs  production  application  easy  due t o v a r i a b l e  for  CONSTRUCTION  more  operations.  that  be  operations  i s difficult  system  a t t h e work  TO  more  facilitate  production  indicate  of  the  runs,  control.  line  ALB  industry  methods  procedures  therefore  OF  construction  continuity  design  t o changes  APPLICATION  product  thus  cycle  must  line,  to interruptions  and  The  projects  5.5  assembly  have design size  construction of  specific  respective  methods  and t h e  74  5.5.1  LIMITATIONS  Even been  though  done  the  number  difficult account the from  a paper  81% or  by  a l l s i t u a t i o n s and to  [86], quoting  optimize  statistics  that:  i s done  error  make i t  either  manually  industrial  a p p l i c a t i o n s do n o t a l w a y s  f i tinto the  mold  specific  computerized  balancing  packages.  methodology,  which  ability  power  ingenuity,  about is  of  the  who  computer, line  prudent  can  use  to  t h e computer  line  t o guide  his  achieve  who  i n the precedence  use any s p e c i f i c  engineer  programming.  i n conjunction  balance."  analyst  then described  line  oriented  i s familiar  t h e r e l a t i o n s h i p s between  not given  Moodie  i s interactive  and p e r c e p t i o n s assembly  computer the industrial  the product  the  assembly  t h e manual methods w i t h t h e  an engineer,  of  workable, "....  offers  of t h e computer,  assembly power  A  t o combine  where  uses  rules  Apparently,  of  and  balancing  c o n s t r a i n t s and  i n order  i n 1969, s t a t e d  have  methods.  the  not  to suit  Moodie  of the b a l a n c i n g trial  line  assignment  alternatives  design.  development  of production  an a l g o r i t h m  published  and  assembly  possible  f o r a l l possible line  good  number  of  to devise  assembly  ALGORITHMS  research  designing  the large  great  ALB  extensive  in  algorithms,  OF  with the insights, with the a  and knows  something  the elements matrix  an i n t e r a c t i v e balancing  good,  which [86]  program  algorithms  the the decision  which but  maker  does  simply through  75 the  manual  the  analyst The  more  line  balancing  process  t o show t h e i m p l i c a t i o n s  above statements  simplistic balancing  all  factors  manufacturing In  to  algorithms which  to  described  the precedence  by  Sequencing  are  uses  the  line  balancing  and  precedence  the  commands a r e :  fail  line  of a that  to  capture  design  relationships  tasks the  work  in  the  t o be  performed  same w o r k  <task  operator work  task with  station  <no.  specify  of the  a certain  just  been  -  University  by  to  the  tasks  Examples  the  same  control  of work  defined.  define  those  [118] i n t h e  Nottingham  the l i s t s  and  set  of  operator  of  work or  at  station.  number)  specified  than  "instructions"  after have  factors  Schofield  at  level  tasks>  the  extensive  developed  procedures  of  of  diagram",  a s e t of high  <list  by  the  some  " f a r more  Program  (NULISP)  MULTI*  decisions.  indicate  and h e u r i s t i c s  capture  that  FIX*  problem  to  environment.  order  JOIN*  feedback  of d i f f e r e n t  the  influence  restrictions  Line  provides  made b y M o o d i e a n d h i s c h o i c e  approach  assembly the  and  AT* to  <station be  performed  special equipped  skilled with  operators) particular number  of  number)  or  by  -  work  particular  a  particular  at  machinery.  <station station  operators.  the  a  specialized  AT*  assign  to  number) be  manned  76  CYCLE*  <desired  cycle  time  assembled  5.5.2  Despite  currently  applied  (1)  OF  ALB  of  PRINCIPLES  the desired  one  unit  of the  TO  CONSTRDCTION  DESIGN  stringent  construction  work  operations  a v a i l a b l e ALB a l g o r i t h m s ,  employed  - define  product.  t h e more  designing  rate>  f o r production  APPLICATION CYCLE  in  production  i n the design  of assembly  to construction cycle  Estimation  of  assignment  constraints  and t h e l i m i t a t i o n s the following production  of  principles  lines  c a n be  planning:  Resource  Requirements  for  Perfect  f o r a 20 e l e m e n t s  assembly  Balance The  example  of l i n e  production  described  illustrates  a single  procedure.  The  precedence the  number  desire  maker. balance  in  section  iteration  first  step  of s t a t i o n s  then  rate  planning.  been  the  becomes a d e s i g n  this line  work  defined  eight  objective  process  balancing tasks  and of  t o meet t h e hour  d a y . The  f o r the decision  c a n be i n c r e a s e d  This  chapter  i s estimation  required  o f 300 u n i t s e a c h  be a c h i e v e d .  of  of t h e manual  or operators  The number o f o p e r a t o r s cannot  2.2  after  r e l a t i o n s h i p s have  production  estimation  balance  when  i s called  perfect backward  77 In  the  backward  traditional  planning  literature informal  and  project  project  guideline  perfectly  Special Cycle As  in  The  elements  previous  of  are  section.  find  applications  on  specific  of  of  resource  experience  involved  and  to overall  this  Interactive  of  there project  reguirements  provide  in  difficulty  past  chapter s i x .  [118],  s i n g l e program  The  in  more  the  can  under  guideline.  Construction  extensive  used  of  of  for construction  line  as  of  by  to  more  include.  the  control  the  design  design  far  the  Schofield  cycle  involved  construction  discussed  principles cycle  are  realistically  instructions  described  above  elements  design  i n the c o n s t r u c t i o n the  the  production  p r o c e d u r e s as  Applications system  assembly  even  balancing  in  for  by  Estimation  resource  Schofield  involved  line  support  the  improvement  can  i n an  productivities  superintendents  conditions  by  t h a n any  operations  dependent  on  personnel  Design  design  extensive  designs.  Instructions  described  the  of  planning,  construction  influenced  because  estimations  the  field  the  highly  for possible  balanced  in  by  because  therefore and  construction  mentioned  are  and  managers  productivity;  (2)  is  p e r f e c t l y balanced is  to  performed  operations  requirements  no  This  conditions  achieving  is  seldom  i t i s only  manner.  construction  the  is  approach  in  can  also  problem. a  are  decision described  78  6.  DECISION SUPPORT SYSTEM  6.0  OBJECTIVES Traditional  approaches  emphasized  the use of  techniques  whereby  closed  form  the design  that  the activity  closed  form  problem  deterministic  that  generated  problem  experience,  personal  personnel  be  solving  variables  and  in  stated  defined  solutions therefore  involved  modeling  t h r e e , we h a v e  cannot  judgment  have  by  a l l the design  o b j e c t i v e . In chapter design  solving  quantitative  c a n be  link  function; design  management  to  solutions  functions  with  the  (DSS) FOR ACTIVITY DESIGN  by  depend  a on  intuition  of the  activity  design  the  process. In  this  support  chapter,  systems  described  management s c i e n c e the  development  involved design needed terms  i n the industrial  literature of  i n designing  an  activity of  five  and  system  environment  modules  improvement  and d e c i s i o n  e n g i n e e r i n g and  studied to assist i n of  the  a construction activity.  design  solution  are first  understanding  of a d e c i s i o n support  definition, design  d e c i s i o n making processes  -  problem  formulation, enrichment.  which  A  would  i s then  processes conceptual  provide the  discussed  recognition, design  i n  problem  analysis,  and  79  In  dealing  brief  with  statements  information  the problem  are  representation.  process  of  physical  dimensions  components  detailed  personnel  technology  that  realistic  described.  The for  management Labour  path assist and  f o r part and  enrichment  instructions  improve plans, for  are  the  also  use i n the  field.  structures  solutions  are  balancing  are  assigned  duration. charts  to  operation  to time  The  than  as  to  an  critical  are adopted  of  to  improvement high  allow  schedule and  guide  process.  rather  be  described  to  assignment  Examples  design  data  and t h e d e s i g n  the operation  the multiple  appropriate  crews  can  analysis  preliminary  called  as  activity  processes.  are  the  requirements  of the operation  multiple  category  management  line  resource  Resources  to modify the  resource  the  assist  design  assembly  assigned  i n the solution  personnel  of  i nthe  f o r describing  Input  of  of  defining  and work  selecting  formulation  in  workers.  method  by  can  only  problem  assists  format  i s presented.  estimating  personnel  individual operation  systematic  and  principles  resources  definition  that  comparing  construction permit  that  of the subassemblies A  module,  the  The f a c i l i t y  technologies in  regarding  problem  i s described.  construction  adopted  made  recognition  level  management  manually produce (M.O.T.)  and t o tactical charts,  80 6.1  THE  CREATIVE  A systematic described  HUMAN  DECISION  MAKING  PROCESS.  approach to the d e c i s i o n making process  by Salvendy  [115]  i s represented  by f i g u r e 6.1  as and  i n v o l v e s the f o l l o w i n g s t e p s :  (1)  Problem  Definition  Understanding need  for  a  obtaining,  Problem  processing  Solving  step  of  to  c r e a t i n g new  (3)  Idea  step  and  to  the  the  recognizing  involves  examination  of  the  searching, raw  data  to  Choosing  Formulation)  solve  and the  process on new  analyzing problem  of  past  This  conceptualizing  the  experience,  situation,  (Solution  the  courses  s o l v i n g process.  best of  and  adapting  developing  and  problem.  Analysis)  solution  action  This step  possible  defined.  s o l u t i o n s f o r the d e f i n e d  Screening  possible  This  inventing,  drawing  experience  s i t u a t i o n and  (Solution  action  involves  problem,  Recognition)  d e f i n e the problem.  Developing, courses  the  decision.  i d e n t i f y and  (2)  (and  from  generated involves  in  the the  t e s t i n g the  set  of  problem set  of  81 possible  solutions  most e f f e c t i v e  Idea  involves idea  the  choosing  the  examining  a tactical  Improvement)  solution the course  i s maintained  develop the  (Design  screening process  focus  and  solution.  Enrichment Preparing  for feasibility  f o r action. of action  f o rfurther and  plan  This  chosen  improvement.  common-sense  step i n the  A  broad  i s employed  to  t o be f o l l o w e d i n c a r r y i n g o u t  solution.  - Situation PROBLEM Problem PROBLEM Many  -  Fig.  6.1:  Defined SOLVING  (2)  Ideas  IDEAS —  DEFINITION  SCREENING  Best  Idea  IDEA  ENRICHMENT  (3)  (4)  Action  C r e a t i v e human d e c i s i o n  making  process  (1)  82  6.2  D E C I S I O N  SUPPORT  In the l a s t have  taken  knowledge systems  i n the f i e l d s  engineering. can  in  such  cannot  completely  making  process  relationship "The  The  as  the  research and development  Godin  solving.  human  process  that  experts  a  expert  However,  [40], r e a l i z e  in  "symbiotic"  and  of  many  computers  the  decision  human-machine  whereby:  computations  churns  through  i n employing  vast  h e u r i s t i c s proved to  of  scheduling  ( i . e . when the  too s i m p l e ) , the human was c l o s e  provide  assistance."  numbers  the embedded  h e u r i s t i c s , but when i t needed help hand  science  d e c i s i o n making  advocate  computer  at  M A K I N G  of management  problem  replace  and  D E C I S I O N  o b j e c t i v e i s to develop  simulate  "experts"  researchers,  AND  decade, e x t e n s i v e  place  that  human  S Y S T E M S  very  flexible,  insightful  [40]  The above system i s a l s o d e s c r i b e d as the " I n t e r a c t i v e Decision  Support  System"  decision  makers  to  p r o c e s s , draw intuition performs and  in the  (IDSS f o r s h o r t ) .  more  closely  on experience the  of  making data  process;  and  those  makers  i n making  i n v o l v e d i n conceptual To  making.  meet Young  the  specific  [135]  qualitative  allows  behavioral judgment and  the  information  q u a n t i t a t i v e a n a l y s i s . The IDSS, however,  decision  IDSS  their  and apply p e r s o n a l  decision  functions  follow  The  computer  processing  cannot  decisions  assist  such  as  designs and i n n o v a t i o n s . needs  proposed  the  of  qualitative  "Right-Brained  decision or  Total  83 DSS"  (TDSS  f o r short)  Young  has d e s c r i b e d  total  decision  qualitative too  aspects  Based  the  making.  the conceptual with  special  on c u r r e n t  support  systems,  environment  emphasis  making  stage  decision  and  understandings the  concept  a conceptual  i s developed  approach support  taken  of  activities.  activity  research  and  decision  design  f o r an a c t i v i t y  system  foractivity  the  management The  data  6.2 a n d f i g u r e process  personnel  base  activity modules:  the discussions  design  process  will  of the  i s represented  6.3. T h e s e  system  n o t be d i s c u s s e d on  design  carried  and  Building  DESIGN  charts  out  by  i n designing construction  management  i n this  design  sections.  design  e x t e n s i v e and p r e c i s e d e f i n i t i o n  five  i s  interactive  of  requires  the  i t  decision  i n the conceptual  realistically  construction  will  on t h e  o f t h e human  i n the following  the flowcharts i n figure  reflect  of a  process,  DECISION SUPPORT SYSTEM FOR ACTIVITY The  design  to the construction  present  While  i n the construction industry.  process  by  decision  of the decision  at  making  6.3  system,  f o rapplication  problem  development  i n detail  support  extensive  design  f o r creative  (DBMS)  shown  of data s t r u c t u r e s  thesis. i n sections be  roughly  6.1  a n d 6.2,  divided  into  84 Module  1 - Problem  This  module  Recognition  represents  management  personnel  draw  familiarize  themselves  with  by  the current  difficulties and  how  that  current  The  of  work  definition  of  requirements  step  personnel  of  have  of problems allows  been  i n the past  which  field  information  them  the particular  represented t o study  type  solved  can then  the  of problems  in be  to  the  past.  adapted f o r  Definition i n problem  solving  t o be  executed  problem  process  technologies,  Using  the dimensions of  these  c a n be  dimensions  accurately  facility  to  dimensions, the  determined.  also  the  Detailed  allows  resource  and f a c i l i t a t e s  the  alternatives.  Formulation  the problem have  design,  i s defining  of the p h y s i c a l  must be d e f i n e d .  3 - Solution  After  This  with  t o be e s t i m a t e d  of design  Module  the type  and s u b a s s e m b l i e s  constructed  study  body  For construction a c t i v i t y  assembly  scope  a  in  situation.  first  problem. the  worked  on  process  I t also  problems  2 - Problem  Module  be  associated  similar  Solutions the  situation.  the  has  to formulate  involves  been a  defined,  preliminary  field  activity  selecting the appropriate  defining  and  management  seguencing  design.  construction construction  85 operations  to  estimating  produce  and committing  equipment  and work  space,  Module 4 - S o l u t i o n The by  computer  of  analyzed  Idle  and c o n f l i c t s to  modifications  Whether  intuition  for  module  4  required terms  seek  the  and  an  be  analyzed The  variables  operations  must  and  are  schedule.  be i d e n t i f i e d for  and  appropriate  Enrichment  the process  t o improve in  identified on  the design  effectiveness. study  t o produce  of both  hardware,  and e f f e c t i v e n e s s .  the  time  field  the preliminary  design  solution can  experience,  design  The f i n a l  and c o s t . F i n a l l y ,  solved and  design  that  analyzed  module  alternatives that  be  c a n be  through  solution  analysis  judgment  process  Iterations  a design  which  problems  improvement  other  through  the  o f t h e management p e r s o n n e l .  to  then  personnel  identified  depends  from  cost  must  of resources  represents  problems  effectively  t o produce  Improvement  management p e r s o n n e l  process.  and  to the preliminary design.  module  solving  - labour,  parameters  management  Module 5 - D e s i g n This  unit,  the defined operations.  solution  design  and  communicated  assembly  Analysis  processed  results  to perform  routines f o r feasibility  values  time  physical  the resources  preliminary design  defined  by  the  3  and  might  be  i s acceptable i n  elements  that  are not  86 normally be  included  short and to  considered  cycle  i n the  achieve  the  The  issues  design  activity  be  crew  set  in  produce  can  be  can  tactical  equipment followed  each  module  Examples  formats  environment  are  s e c t i o n s . Through  d e c i s i o n support  described.  input/output design  a  to  process  also  plans  -  schedules  i n the  field  for a construction project.  following of  design  assignments, that  involved  design  will  computer  goals  activity  design  schedules,  i n the  conceptual  final  schedule,  sub-trades  addressed  i n the  are  that also  of  discussed this  system data  can  process,  for  presented.  used  a  activity  structures  be  and  in  and the  3 O  a a r n  t  SO O 09  r  n  3  SO RI O  x o o c  IT  n  o ft  z  Rev leu Construction Mathods  o  z  \ /  Specifications Construction DrawIngs  »0 so o a n Rl  T  Quantity / Survey / —  X  \  o  Break Down t o Smaller Units  Definition of Unit Dimensions  a >  H  >  M  a >  z  M  Ui  Select Construction Technolog Jes  o  z  I  3 o o a r  Grouping of Operations  RI  m  3 > Z  >  Review I Construct I \ Methods  ra 3 Rl  DefIne P-Matrlx  W  o n a H  (  S e l e c t from Standard P-Matrlces  Z  /  J  CA  * Ui H  Rl  3  O CO  M o  3 cn  z  o  3 a  > M o  z  CO  Figure  6.2  F i g u r e 6.3  co co  89  6.3.1  6.3.1.1  REPRESENTATION  In  the  management similar  design  personnel  projects  methods  and  therefore of  MODULE 1 - PROBLEM  of  firm's its  ability  key  represented environment  for  training  of  project  i s  and knowledge to  represent  by t u r n - o v e r  Experience  c a n a l s o be u s e d less  a  the a contracting  i s not affected  experienced  that  most  be  and  i n  knowledge  t o p r o v i d e an construction  information:  represents  personnel  closely  and  quickly  represent  data.  otherwise I t could  be  lost  (2)  two broad  detailed  information identify  which  the  past  situation.  and c r e a t i v e  amidst  be i n t h e f o r m  by  (1)  the present  includes d e s c r i p t i o n s of innovations would  represented  statements,  The former  management  can  project  data.  project  of  that  with  of c o n s t r u c t i o n  The a b i l i t y  ensure  knowledge  quantitative  which  experience  the experience  help  formats  descriptive  It  on  success  personnel.  qualitative  project  The  personnel.  and  classifications  help  knowledge  field  personnel.  Experience  can  their  t o compete  i n proper  management  on t h e i r  dependent  management  activities,  t o draw  technologies.  and knowledge  INFORMATION  construction  have  t h e k e y management  experience  OF P R O J E C T  and apply  highly  RECOGNITION  designs  the quantitative of brief  statements  90  describing  the  overall  systems  and  and  difficulties,  a  the  technologies  project.  The  information database are  are  latter  subassembly  in  of  carried  of  of  type  storage  of  project  operation  in  quantitative  computer  this  out,  involved  detailed  of  dimensions  production  innovations  terms  Examples  components,  operations  and  type  demanding  detailed  performance,  employed,  solutions  maintenance.  the  project  and  information  assembly  definitions  and  and crew  ass i gnments. At  present,  records  of  resides  in  reason this  and  reference.  projects;  minds  the  limited will  being  environment  information  construction  the  module  environment design  past  few  can  of  be  key scope  body  will  also  of  management of  this  described  developed.  be  the  firms  in  It  is  act  as  collected  and  organized  information  personnel.  thesis, the  hoped a  have  tool  no  For  only this  details  activity  of  design  that  the  by  which  project  for  future  processed  activity  91 6.3.2  The affect  level how  solution  MODULE  of d e t a i l  realistic  i s .A  dimensions  of each  each  category  the  work  tasks  These  work  to construction operations.  CURRENT  management described  the  planning  to  quantities  tasks  AND  e.g. area  can define  first  subassemblies  lines;  o f work  i n each  manually  or derived  from  In  order  to identify  t h e most  for  a  construction  activity,  process to  available f o r  the f a c i l i t y  the  by  a r e then  produced  effective  the field physical  breaks,  construction  which  i n the detail  typical  logical  operation  the  DEFINITION  planning process,  along  values  assists i n  be g r o u p e d a n d  t h e problem  divide  of  of the  construct  currently  the subassemblies  the corresponding  contents  can then  do n o t p r o v i d e  and  and t h e dimensions  PROBLEM  systems  In theactivity  personnel  into  column  groups  and  personnel  management assembly  PRACTICE  tools  above.  by t h e  required  assigned  construction  c a n be d e f i n e d  definition  product.  Modeling  design  component, e.g. t h e rebar This  will  t h e subsequent  slab,  physical  6.3.2.1  i s defined  components,  bay of a f l o o r  slab subassemblies.  identifying  DEFINITION  a problem  and e f f e c t i v e  i t s subassembly  thickness  floor  i n which  construction project  of  work  2 - PROBLEM  such  as  assigned  i n  operations.  must  be  The  calculated  by t h e e s t i m a t o r . c o n s t r u c t i o n method  one h a s t o experiment  with  92 different the work of  groupings content  quantities have  t o be  6.3.2.2  One for  of  work  achieved  (1)  the  used  of  the  thus  of  groupings to the  the  work  operations  will  thus  construction  assignment  Because  can  be  is  each  subassembly  The  following in this  provide  an  detailed  routines  required  resource  assist  in  by and  can  be  manner:  accurately  the resources  to  component benefits  simple  calculate  used  to  system  c a n be d e f i n e d i n d e t a i l  operations; the  work  by  content  computer,  of  the  to  can  the  be  work  perform  requirements the  operations  different  ways  for  construction  in  process  c a n be s t u d i e d  subassemblies formulation  module  support  resource  process.  the  calculated  to  DSS  decision  specified,  the computer and  THE  the  the problem  the dimensions  of  of  component.  by d e f i n i n g  by  AND  the problem  the dimensions  calculated  (2)  and  requirements  Definition  i n which  contents the  objectives  category  Using  time  changing  tasks assigned  change  DEFINITION  Problem  specifying  will  the resource  PROBLEM  the  t h e work  thus  recalculated.  environment  each  are changed,  operations  and  units,  of the o p e r a t i o n s . Every  subassemblies  corresponding  of the subassembly  of  grouping  the  readily.  can  be the  solution  93 (3)  By d e f i n i n g assembly  the dimensions  unit,  dimensions  the  of  and  impact  work  of  non-typical  content  of  differences  assembly  each  i n the  units  can  be  assessed.  6.3.2.3  PROBLEM D E F I N I T I O N 6.4(a)  Figures the  dimensions The  of a typical  name  divisions  to  theproject  by  detailed  components  division  In  can then  t h e resources  finishing  operations,  and  theproductivity  which  will  required  content  factor  therate  (Prodv'  involved of  a  assembly  of similar This  units  i s followed  of t h e subassembly The d i m e n s i o n s Any  from  assembly  that  of the  and modified. entered  a r e used  f o r formwork  f o r t h erebar  e.g. forming  reduce  t h e areas  t h erebar  of defining  the  entered.  deviates  required  difficulties  subassembly,  number  be i d e n t i f i e d  shown,  calculate  resources  describing  are first  FORMAT  component.  components.  that  INPUT  t h eprocess  a r eentered.  category  dimensions  the  COMPUTER  of thedimensions  assembly  t h e example  possible  group  a n d t h e work  division  i n  and t h e t o t a l  definition  with  show  assembly  used  assembly  the typical  typical  be  (orunits)  in  of  a n d 6.4(b)  AND  and  i s used  to  concrete  to calculate  installation  operation,  F.) i s u s e d  to reflect  i n  constructing  irregularly  of construction.  shaped  the area,  Figure  6.4(a):  Select  assembly  ASSEMBLY DEFINITIONS Enter  :  component  :  I Elev.  Number o f Assembly D i v i s i o n s  S e l e c t Assembly Component t o D e f i n e  > "'-SUB " %  Figure  6.4(b)  \  :  COLUMNS  Specify  define  SUPERSTRUCTURE  Name of Assembly D i v i s i o n  Enter Total  to  1  :  I 25  1  SLAB  ELEV. CORE  dimensions  of  WALLS  subassembly  a n d work  category  components  T Y P I C A L ASSEMBLY COMPONENT DIMENSIONS  Assembly Component I Bay )  :  SLAB  I Area 1 2 < M^ >  (Slab Thkn.  [Rebar  Content!  < mm >  < tons/M > 1.0  A-1  90  150  A-2  100  200  IProdv' F . J  2  0.90 1.00 1 .00  B-1  100  200  I.I  B-2  100  200  .1  1.00  B-3  65  150  .9  0.60  B-4  100  200  .1  1 .00  B-5  100  200  .1  1.00  C-4  100  200  .1  1 .00  C-5  85  150  .0  0.85  Copy D l m e s l o n s t o O t h e r Assembly D i v i s i o n s  :  Modify  Yes  Dimensions  In Assembly D i v i s i o n  E n t e r Assembly D i v i s i o n  Figure  No. t o M o d i f y  6.4:  : :  Yes /  /  No  No  t 24 1  Problem  definition  95  6.3.3  As  stated  construction in  MODULE 3 - SOLUTION FORMULATION  i n  section  planning  fails  h a s t o be c o n s t a n t  construction  operation.  actual  construction  labour  resources  rather  than  The  activity  construction  of this  that  resource of a  t o c o r r e c t l y model t h e process.  F o r example,  as i n d i v i d u a l  workers  i s t o provide  reflects  as  the  practiced has  a  problem  realities  of  i n the field.  The  been  divided  into  the  processes:  Review  (2)  Define  (3)  Sequence  defined  (4)  Estimate  and a s s i g n  Some  A  i n  activities  theentire duration  fails  module  process  (1)  processes  i t assumes  design  that  activities  formulation  following  construction  t o be a s s i g n e d  environment  solution  practice  as crews.  objective  solving  over  I t also  have  current  t o model  a r e a l i s t i c manner. F o r example,  consumption  (1)  4.5,  and s e l e c t  construction  technologies;  operations; operations;  of the features  and  resources. incorporated  into  the  foregoing  a r e as f o l l o w s : data  structure  for  technologies  i s described.  construction  technologies  representing  construction  The c o m p u t e r i z e d can  be  used  record to  of  assist  96  (2)  management  in  technologies  i n the  By  using  detailed  of  subassemblies  in  the  into  The  by  the  defined  a  the  of  of  the  physical  dimensions  components  developed  operations to  be  are  included  operations.  d e s c r i b i n g an  for  between of  process.  subassemblies  format  percentage  construction  module,  operations  relations  of  category  Definition  in matrix  precedence as  work  content  sequencing  selection  definition  selecting  work  different  solution  and  Problem  defined  (3)  the  comparing  clarity. operations  the  activity  The  lags  can  in  be  corresponding  is the  defined operation  duration. (4)  Using  the  resources are  principles required  estimated  assignment (5)  by  resources  rather  than  assigned  d u r a t i on.  assembly  perform  computer  to  line  balancing,  construction assist  in  the  operations  the  resource  process.  Labour  be  to  of  are  assigned  as  individual  to  an  to  operations  workers.  operation  for  Resources a  percentage  as  crews  can of  also its  97 6.3.3.1  REVIEW  In  a  It  i s of prime  also  imposes  requirements.  Each  choice into  a  unit  trade-off and c o s t .  production  certain  production  r a t e , however,  rate  c o s t . Whether  rate  i sappropriate  an  balanced. activity,  parallel,  will  depends  say  n o t be i n c r e a s e  both  operations  i.  using  must  design  therefore activity  technology might  even with  technologies  crew  size  c o s t s . The evolves  production  rate  has a  increase  higher  the  overall  a t t h e expense  of the  of  unit  production  the operations  the overall two  c a n be  production operations  rate in  by i n c r e a s i n g t h e p r o d u c t i o n  rather, theproduction  be b a l a n c e d ,  with  resource  often  that  a high  a l s o be i n c r e a s e d must  time.  n o t be a p p r o p r i a t e f o r  not  consisting  alone,  labour  minimum  on w h e t h e r  F o r example,  o f one o p e r a t i o n  from  will  a technology  rate  activity  and  o f an a c t i v i t y  extra  properly  between  A production  situation  thecycle  a l s o has a s s o c i a t e d  technology  problem  on  production  the production  and thus  possible  technology  of  I t affects  constraints  of  TECHNOLOGIES  the choice  importance.  of construction  (time)  the  project,  certain  because  of  CONSTRUCTION  of the construction operations  assignments  a  SELECT  construction  technology rate  AND  higher  rates of  proportionately, i.e. i n order  to benefit  unit production  rates.  98  6.3.3.1.1  CURRENT  PRACTICE  AND  SELECTION  OF  TECHNOLOGIES Currently and  systems  own  This  one. Instead,  management  process  encourage  involves  innovations  SELECTION  facilitate  estimation In suggested in and  draw  estimates  on  format of cost  to  f o rcoding  of  AND  technology  does  little of  new  allow  THE DSS  alternative must  a r e intended  construction  be c l a s s i f i e d  f o rand coded  comparison  and  by  i n a  accurate  requirements.  discussion,  and s t o r i n g  database.  best.  technologies.  and resource  the following  approach  OF TECHNOLOGY  they  of  their  a n d do  at  considerations  available technologies  a computer  t h e most  This  and  t h e study  categories  systematic  rough  reguirements.  6.3.3.1.2  work  and s e l e c t  o f one o r two a l t e r n a t i v e s  i nconstruction  the  t o study  technologies  developments  technologies,  techniques  thefacility  construction personnel  study  and resource  To  planning  of a v a i l a b l e construction technologies  formal  latter  costs to  construction  knowledge  limited  construction  do n o t p r o v i d e  alternative suitable  available  a  data  structure  construction  The a t t r i b u t e s  describing construction technologies  used  i s  technologies  for classifying  a r ea l s o  described.  99  Figure  6.5(a):  Select  technology  Select Work Category-Group  REBAR  POURING  Figure  6.5(b):  COLUMNS  Compare  EFCO F l o a t i n g  < M /Mn-hr > 2  j  FORM-Ezy  6.5:  Review  WALLS  Slab  I Hardware ) [ U n i t Cost ] < cnd$/M  2  >  I Crew Make-Up 1 [ Ratios ) < Carpenter >  < Gen. Labr >  4.8  37.50  0.9  0.1  6.4  47.75  0.8  0.2  Review detailed descriptions of selected technology :  Figure  FINISHING  technology  t Unit Production 1 [ Rate 1  EFCO F l o a t i n g '  CURING  ELEV. CORE  and s e l e c t  Select Slab Formwork System: I System!  OTHERS  SLAB  Select Assembly Component : *"i  SUB-TRADES  CONCRETE  FORMWORK  Select Work Category :  S L A B " ' ,'  category  to Review Technologies :  CONCRETE  CIVIL/SITE  FORMWORK  by work  and  select  Yes  construction  /  No  technologies  100  6.3.3.1.3  ATTRIBUTES  Figures formats  6.5(a)  used  OF  and  to assist  CONSTRUCTION  6.5(b)  show  TECHNOLOGIES  t h e computer  input  i n selecting alternative construction  technologies. The  f o l l o w i n g a t t r i b u t e s used  technology  (1)  i nselecting construction  a r e noted:  Work  Category  Group,  Category  and  Assembly  Component  These the  work  a t t r i b u t e s , a s shown  category  intended.  They  technologies. retrieved their  by t h e s y s t e m  as  this  f o r  technology  classifying  technologies  identify i s  construction can  then  be  user  f o r comparisons  by s p e c i f y i n g  The  work  structure  categories  a  technologies;  place  used  classifications.  used  (2)  are  6.5(a),  the construction  Construction  work/component  in  f o rwhich  i n figure  breakdown  described  classification a comprehensive  i n chapter  scheme scheme  f o r  by  t w o c a n be construction  has n o t been  developed  thesis.  Unit  Production  Crew  Make-Up  Unit  Production  a  operation  single using  Rate,  Hardware  Unit  Cost  and  Ratios  unit  Rate  describes 2  3  (M ,  M ,  the selected  t h e time  etc) of  technology.  a  reguired  to  construction  I t determines the  101 production system  rate  for  of  the  activity  design,  resource  requirements  duration.  Higher  at  the  to  of  time  6.5(b),  the  and higher  cost  two-fold:  system  cost  hardware.  a  to  achieved in  the  operation only  words,  the  is  a  shown  FORM-Ezy  the  usually  other  example  support  calculate  specified  process  p r o d u c t i v i t y of  trade-off in  figure  i s achieved  at  hardware c o s t .  associated  the  decision  used  cost;  For  with  hardware cost and  represents  the  be  selection  cost.  the expense of a higher The  is  achieve  higher  technology  between  it  In  p r o d u c t i v i t y can  expense  construction  operation.  for  a construction  labour  either  Labour  separately,  because h o u r l y  geographic  location  of  c o s t . Hardware Unit  renting  cost  or  would  labour the  technology  Cost  fabricating  be  best  and  the  specified  r a t e s would depend on  project  is  other  the  project  conditions. Crew Make-Up Ratios of  men  reguired  for  identify  each  the  labour  r a t i o s of the  type  in  numbers  employing  the  construction install will  a  technology. For example, to dismantle and 2 240 M f l o o r s l a b using the EFCO F l o a t i n g form 2 2  require  50  carpenter-hours hours  (50  man-hours (50  Mn-hr  Mn-hr x 0.1).  $9,000.00 (240 Displaying technologies  M  2  (240 x  The  0.9)  M  / and  4.8 5  r e n t a l cost  M /Mn-hr) general  -  45  labourer-  of formwork w i l l  be  x $37.50). the  three  side-by-side  can  attributes  of  construction  a s s i s t management i n s e l e c t i n g  102  an  appropriate  technology  for  the  preliminary  design  solution. Other such  as  attributes useful  minimum  involved,  can  crew  also  the  involved  in a construction  general,  level  of  treatment  user  breakdowns  detail  requirements  included  example,  In  system  be  size  i n the a c t i v i t y  may  of  i n the  wish  method,  and  design the  process,  work  attribute  list.  to  review  t h e work  as  shown  i n Figures  construction  technologies  to  are not r e a d i l y a v a i l a b l e ; t h e r e f o r e ,  i s not pursued  further  in this  thesis.  tasks For tasks 6.6. this their  103 F i g u r e  6 . 6 ( a ) :  R e v i e w  work  t a s k s  EFCO F l o a t i n g S l a b Formwork Literature Slab  **  F i l e  Formwork  INSTALL  01  Set  02  Lower  support  03  Strip  slab  04  Attach  05  Position  06  Roll  07  Crane  08  Slab  swing-out  09  Clean  and ol1  10  r o l l e r  edge  1nstaII  form  &  4  form  t a s k s  30  1  30  30  1  15  15  1  30  30  **  In minutes  >  1 bolt  at bearing winch  13  Position  14  Rol1  15  Crane  16  Slab  17  Install  r o l l i n g  o f  blocks  points  o u t and re-set at bearing  Review  20  20  80  No. of Units  form o u t  1" b o l t  5  1  Tasks  scaffold  up 4  4  s e 1 e c t e d  S y s t e m Work  O F FORM  tugger  Source:  30  6/100sf  46  90  180  1  Attach  6.6:  120  1  pane 1  Remove  Figure  320  15  784sf  12  hook  40  8  pick-points  11  swing  8  ahead  points  a l l time  slab  Total Time  (1 e n d )  EFCO F l o a t i n g S l a b Formwork  <  Unit Time  and reset  SPLITTING  work  1  Page  No. of Units  scaffold  work  :  page  1 of  3  **  form  rail  out t o  R e v i e w  **  FORM  winch  f11ler  6. 6 ( b ) :  Tasks  -  2 0 M b y 10 M B a y  >  bracket  hand  r o l l i n g  hookup  :  In m i n u t e s  brackets  t e c h n o l o g y  SlbFm-012  AND DISMANTLE  tugger  slab  No. :  support  s e l e c t e d  S y s t e m Work  Dimension  < a l l time  o f  blocks  tasks  t e c h no logy  4 Men &  page  2  Page  :  Unit Time  Total Time  4  5  20  1  30  30  1  15  15  1  30  30  4  5  20  1  20  80  4  5  20  Crane  2 men  -  of c o n s t r u c t i o n  Economy Forms C o r p o r a t i o n ,  Comments  2 of  3  Comments  4 Men &  Crane  technology  D e s M o i n e s , I o w a , USA.  104  6.3.3.2  DEFINE CONSTRDCTION  Construction by  completion  the  problem  method  an  definition  undesirably  considerable To  large  idle  shorten  major  divided  into  of  five  first the  of  be  required Changes  definitions  assembly i n three  and c y c l e in  instead  of a  this  concrete i s  method  could  have  be a c c o m p a n i e d by  and because  assembly  of other  i s often  and rebar  can then  section  s a y ,Bay-Al  could  t o Bay-C5.  i n three  be p o u r e d and  fewer  By  i n  c a n be  sections  c a n be i n s t a l l e d  i s completed.  i n the  and f i n i s h e d i n rebar  are  being  construction  constructing  formwork  units  the could  be r e d u c e d . method  operations  assembly single  assembly  and s o on u n t i l  sections,  economic  constructed  a floor  formwork  of construction  sections  installation  before  and could  construction  i f the floor  and rebar  c a n be p e r f o r m e d  time  example,  assembly  key trades.  while  i n t h e second  assembly  as a s i n g l e  sub-assemblies,  concrete  in  floor  F o r example,  The formwork  section  the floor  floor  the floor  defined  construction  simple,  time  time  operations  section,  installed  for  sections.  bays.  first  cycle  i s accomplished  components  a r e completed  Although  time  fifteen  Construction  slab  cycle  considerations, several  unit  The s i m p l e s t  t h e formwork  floor  and f i n i s h e d .  process. t h e whole  f o r example,  the complete  poured  assembly  of a l l the subassembly  i s to construct  section; for  of a floor  OPERATIONS  will t o be  require  changed. F o r  i s constructed  section,  the  i n  the operation,  three say  105 Install  Slab  operations, Slab  Formwork,  has  say, I n s t a l l  Slab  Formwork S e c t i o n  to  be  redefined  Formwork S e c t i o n  #2 and I n s t a l l  Slab  as  three  #1,  Install  Formwork  Section  #3.  6.3.3.2.1 The figures by  D E F I N I N G AN O P E R A T I O N process  can  defining  an  operation  6.7(a) and 6.7(b). An o p e r a t i o n  i t s work  process  of  categories  of i d e n t i f y i n g  facilitate  accounting  of  as  shown  project  in  identified 6.7(a).  The  by i t s work c a t e g o r i e s  project  the c u r r e n t  is first  in figure  the o p e r a t i o n  collecting  i s shown  information and  for  for estimating  cost the  c o s t s of s i m i l a r p r o j e c t s i n the f u t u r e . A f t e r the o p e r a t i o n is  i d e n t i f i e d by i t s work c a t e g o r i e s , the d e f i n e d  of the subassembly components and work category e.g. rebar user  the dimensions contents  of  i n each  can then d e f i n e  the f l o o r  slab  subassembly,  dimensions components,  subassemblies, and  can be r e t r i e v e d . The  the work assignment of an o p e r a t i o n by  s e l e c t i n g the r e s p e c t i v e subassemblies to be i n c l u d e d i n the operat i on.  6.3.3.2.2  DEFINING RELATED  Construction categories  can  assignments,  operations  be  related  i.e.  the  OPERATIONS  that  belong  to each same  or  to d i f f e r e n t  others  by  similar  their groups  work work of  106 subassemblies are assigned shown  in  figures  RbrSlb-1,  Rebar  to the o p e r a t i o n s .  6.8(a) Floor  formwork o p e r a t i o n  and  Slab  6.8(b),  Section  the  #1,  In the example  rebar  is  operation  related  to  the  InsSlbFm-1, I n s t a l l Slab Formwork S e c t i o n  #1. Normally,  both  operations  have  a s s i g n i n g s e l e c t e d subassemblies set  of f l o o r  C-1,  have  be  InsSlbFm-1. The  B - l , B-2,  assigned  once again,  the  operations  as  illustrated  The  assignment the  the  user  assignment or add  the  the  Problem  work  A-2,  of  formwork  can  s l a b assemblies  A-1,  above  manner  in figure  the  module.  the  rebar  In  to of  definition  be the  installed  can  subassemblies  process.  be  The  already  be  as  to  operation. is  then  defined  work  reguired.  The  i s then c a l c u l a t e d  dimensions the  defined  operation  operation  specified  example  operation,  to the formwork o p e r a t i o n ,  rebar  content  of  component  A-2,  developed,  can  6.8.  related  by  RbrSlb-1.  or d e l e t e sub-assemblies  category  and  operation,  environment  accept  Thus, a  repeated  operation,  the  by  B - l , B-2,  r e l a t e d to an already d e f i n e d  Definition  assignment  related of  work  defined  operations.  q u a n t i t y of work of the d e f i n e d o p e r a t i o n using  be  must then be  design  in  is f i r s t  retrieved,  the  floor  activity  be d e f i n e d work  the  to the rebar  related  conveniently  to  assignment process  and C-1  In  to the  s l a b subassemblies, say A-1, to  assigning,  to  shown,  RbrSlb-1  InsSlbFm-1, the  calculated specified  from in  the  has  in the  been  quantity the  rebar  problem  107  6.3.3.2.3 An  REDEFINING OPERATIONS  operation  input/output deleting  format  this  total  quantity  calculated  be  similar  subassemblies  Using  resource  can  from  new d e f i n i t i o n , o f work  resource  assignment  redefined to figure  6.7(b),  t h e assignment t h e computer  and resource  requirements process  using  a  computer  by a d d i n g  or  o f an o p e r a t i o n .  can recalculate the  reguirements.  a r e used  How  these  i n guiding the  i sdescribed i n section  6.3.3.4.  Figure  6.7(a):  Select  operation  Select Work Category-Group  :  to define  CONCRETE  CONCRETE  CIVIL/SITE  COLUMNS  REBAR  INSTALL  Selected Slab Formwork System :  INSTALL  Assign  s l a b formwork B A Y < A 1 , A 2 , B 1 , B 2 , C 1 > 1 EFCO F l o a t i n g No  Change selected system :  Install  Slab  / Yes  subassemblies  t o an  operation  InsSlbFm-1 slab  formwork  BAY<A1,A2,B1.B2.CI>  Selected Slab Formwork System :  EFCO F l o a t i n g  Slab  Move cursor and press <Enter>/<Del> t o Include/remove t Bay 1  A-1  ( Area 1 2  0.90 1.00  100 100  1.00 1.00  B-3  65  0.60  B-4  100  1.00  B-5  100 90  1.00 0.90  B-1 B-2  C-1  Figure  6 . 7 :  assembly.  IProdv' F l  90 100  A-2  FINISHING  I InsSlbFm-1 1  [ Install  Enter Description :  Operation :  CURING  DI SMANTLE  Enter Name of Operation :  6.7(b):  WALLS  DELIVERY  Select Work Category Sub-Component :  Figure  ELEV. CORE FORMWORK  Select Work Category Component : FORMWORK  OTHERS  SLAB  Select Work Category : SLAB  SUB-TRADES  Defining  an o p e r a t i o n  Figure  6.8(a):  Select  related  Select Work Category-Group : CIVIL/SITE  operation  SLAB  Select Work Category Component :  t InsSlbFm-l Install  Change selected system :  Operation :  CURING  FINISHING  I S l a b Rebar BAY<A1 ,A2,B1 ,B2,C1 > 1  Selected Slab Rebar System :  Review  WALLS  I RbrSlb-1 1  Enter Related Operation :  6.8(b):  ELEV. CORE  DELIVERY  Enter Name of Operation :  Figure  OTHERS  REBAR  REBAR  Enter Description :  SUB-TRADES  SLAB COLUMNS  FORMWORK  define  CONCRETE  CONCRETE  Select Work Category :  to  and  No  modify  RbrSlb-1  /  ]  In  place  Yes  assignment  Related to :  of  operation  InsSlbFm-l  Rebar S l a b BAY<A1,A2,B1,B2,CJ> Selected Slab Rebar System :  Install  In  place  Move cursor and press <Enter>/<Del> to include/remove assembly. I Bay 1  (Rebar Content!  [Prodv* F!  < tons/M > 2  A-l A-2  .0  0.90  .1  1 .00 • •• •  B-1 B-2  1.00  B-3  0.60  B-4  1.00  B-5  1 .00  C-1  1.00  Figure  1.00  6.8:  Defining  related  operations  110  6.3.3.3  SEQUENCE D E F I N E D OPERATIONS  6.3.3.3.1  OPERATIONS  Operations must  which  project design  i s  problem  The  by  of operations  industrial  engineering,  between  operations.  advantage  of  immediate  simplicity  operations the  predecessors  This  problem  line  on t h e s c r e e n  the  operation  defined  and  and  process  under  operations  sequence  i s a  of which  or  This  requires  clarity.  by a d d i n g  P-matrix  format  However,  (or  of  has t h e when  the  the  matrix  searching  f o r the  c a n become  tedious.  a column  The p r o c e s s  format  of each  theseguential  t h e immediate  the cursor.  i nmatrix  the  the size  successors  identifying  successors  matrix  manually  shows  by  t o represent  thus  of  c a n be s o l v e d that  other  i s defined  o r immediate  relations  increases,  the best  and  experience.  i s o f t e n used  of  assemblies  technological  the solution  precedence matrix)  number  physical  predecessors  In  P-MATRIX  but not n e c e s s a r i l y unique  Determining  construction  immediate  THE  construct  governed  i n itself,  sequence  operation.  to  i n a specified  constraints.  considerable  the  defined  be p e r f o r m e d  sequence  SEQUENCE AND  i s shown  or a  comment  successors of  of  sequencing  i n f i g u r e 6.9.  Ill  E n t e r A c t i v e Assembly D i v i s i o n :  ENTER  [ 4 1  IMMEDIATE SUCCESSORS OF  IType(s) of r e l a t i o n ; Type: Opratlon 1 .D.  Lag  1 = FS,  OPERATION:  In ( ^ d u r a t i o n ) o r ( h r : m l n ) l  2 = SF,  3 = SS,  4 = FF  Assm* Div.  2  3  4  5  6  7  8  9  DsmSIbFm-l  3  i;0  0  0  0  0  0  InsSlbFm-1  4  *  0  2  I;0  0  0  0  i;0 0  0  0  3  RbrSlb-J  4  *  3;80*  i;0  0  0  0  0  4  SIvSlb-l  4  0  0  0  0  0  0  0  0 »  0  1  5  CncrSlb-1  4  6  CureSlb-1  4  7  1nsSlbFm-2  4  8  RbrSlb-2  4  9  SlvSlb-2  4  Operation: R b r S l b - 1  Figure  6.9:  •  •  »  *  Successors:  Seguencing  3,  SlvSlb-1;  4, CncrSlb-1;  operations  - the P-Matrix  0 0 9;80*  •  112  6.3.3.3.2  OPERATIONS  There  are four  finish-to-start,  l a gvalue.  time  lags.  Each  In reality, Thus,  every  a change  must To  d a y . When this  when  percentages  of  operation  by  l a gvalues  a r e entered  i n  operation  durations  useful  way  of  durations  are  describing  are decision  i n time  t o the operation  of changing  suggested  that  units,  duration, the  the  l a g values  be  be  When  computer to  the durations  lags  durations.  changed,  the  and  described  operation  the process  i s  recalculate  start-to-start,  manually.  i t  are  i s a  i s made  operations,  durations  r e l a t i o n s h i p s , namely  the l a g i s defined  be r e c a l c u l a t e d facilitate  LAG C A L C U L A T I O N S  relationship i s further  however,  variables.  lag  1  e.g.  parameters,  time  sequential  T r a d i t i o n a l l y , these  units,  constant  typical  AND  start-to-finish,  finish-to-finish. a  SEQUENCE  used  of  entered  the  can  as  operation  automatically  i n the  network  analys i s .  6.3.3.3.3 A  REPETITIVE  repetitive construction  number  of  identical  Construction that  carry  or  an o p e r a t i o n  by t h e p h y s i c a l out  construction  the  project  very  of an assembly  performs  occupied to  CONSTRUCTION  AND  assembly  i s initiated  at the location  facility.  operations  of the assembly.  P-MATRIX  i scharacterized  similar  unit  THE  Other  required This  units.  by one crew  which  crews to  by a  will  then  follow  complete  i s the sequential  be  the crew  113 system  described  operations called  the  units  construction some c r e w s  are a  construction  overlap  dismantling  be  the  working  crews  from  assembly performed  must  operations depends  on  operations complete  from  i n each the  the  for  example,  has  on  at  3rd  formwork  the  or  next  In  the while  initiated cycle  any  two one  in and  could or  more  time  the  a the  operations  while  the  as  of  other.  particular  and  formwork  construction  cycle  i n s t a l l i n g crew  could  cycle  floor  construction  to  (or  4th  reassignment is  critical  of  to  labour  avoiding  conflicts. the  one  interface  cycle on  to  division  in  to  must which  the  construction cycle  the  which  identified.  degree  defined  the  example,  (unit)  be  in  For  clearly  division  is  each  that  transition  resource  transition  assembly  identified  assigned  i n progress  4th  cycle  identify  of  their  crew  working  smooth  one  t i m e and To  the  The  of  construction  be  assembly),  on  sequence  c o n s t r u c t i o n c y c l e . Thus,  can  are  be  building,  performing  other.  floor  assembly).  idle  independent  cycle,  crews  typical  can  not  high-rise  cycles  each  cycle  operations,  i t s operation(s)  construction  complete  a  of  i n i t i a t e d another  3rd  construct  typical  are s t i l l  completed  the  the  of  [ 1 2 ] . The  cycle".  sequence  assembly  (or  to  "typical though  distinct  have  Bolinq  required  Even  a  by  an  The be  an  next,  defined the  cycles  the  operation  extent  P-matrix of  between  to  cycles must  assembly  specific is  which  i n the  being the  P-matrix  overlap. describe  unit.  and  The the  114 In units  addition,  exists  deviations enough  of these  design.  6.9 s h o w s  quantities  automatically dimensions  The  significant construction  non-typical  be  format.  and  considered  typical  i n the cycle  from  i s being  assembly  assembly  cycle  and  design  The  be  total  calculated  category-component  3 and 4  defined  i n  process.  DsmSlbFm-1,  Slab  Dismantle  assembly  (Assm  predecessor  Formwork  Slab  Section  1  Formwork  D i v . 3) i s  to the  operation  #1, o f t h e  4th  (Assm' D i v . 4 ) .  operation  Start-to-Start  can  divisions  t h e immediate  Install  the defined  formulated.  operation  t h e subassembly  definition  as  of sequencing  The c o n s t r u c t i o n  #1, o f t h e 3 r d f l o o r  InsSlbFm-l,  RbrSlb-1.  also  f o r each  operation  identified  Sleevings  between  assembly  of f l o o r  problem  The  be  to the typical  an example  i n matrix  the 4th floor  floor  might  Sometimes, t h e  SEQUENCING OPERATIONS WITH THE P-MATRIX  operations  Section  units  modification  must  projects.  assembly  process.  Figure  the  of non-typical  repetitive  non-typical  cycles  6.3.3.3.4  work  number  Transitions  construction planning  small  f o r most  to require  cycle  of  a  RbrSlb-1,  relation  i n Slab  with  #1, w i t h  Rebar  Slab  the operation a  l a g of  Section  #1  SlvSlb-1,  has a Install  80% t h e d u r a t i o n  of  115  6.3.3.4  ESTIMATE  The  purpose  technologies solution, costs, of any  special  and other  accounts  project.  space  site  constitute  thesis.  idle  site  of this  between  manner  reflects  assigning  processes labour  construction assembly  line  that  helps  h a s t o be  ensure  i n a smooth  models  and t h e system  developed,  as a s p e c i a l  resource  subsection  where  the  scope  of this work t o be  i s to describe  assignment  resources  that  manner.  environment  i nt h eresource  i s provided  The  resource  thecost.  design  this  environment that  t o minimize  i sbeyond  by c o n s t r u c t i o n o p e r a t i o n s .  assists  Use o f hardware and  t h ecomputer  shared  of  planning i s  resource  c a n be t r e a t e d  objective  careful  cost of  theuse of schematic  however,  that  The c o s t  planning  space,  facility  constraints.  canprogress  requires  In the activity  The  equipment  time.  another  Proper  interface  Treatment  and s p e c i a l  portion of thetotal  be m a x i m i z e d  planning  a graphics  effective  Therefore,  construction operations  user.  project  f o r a major  carefully.  Detailed and  time  construction  t h e most  of labour, hardware  e q u i p m e n t must  managed all  i n terms  different  i s t o design  t o eliminate labour  Work  RESOURCES  f o r evaluating  construction  required  ASSIGN  and methods  within  labour  AND  a  p r o c e s s . An  c a n be a s s i g n e d  i n a  t h ea c t u a l c o n s t r u c t i o n p r o c e s s . of estimating  crews  operations balancing  and will have  special  resource  resources  be d e s c r i b e d . been  requirements  adopted  and  t o perform t h e  The p r i n c i p l e s o f for estimation of  116 resource crews  requirements.  rather  space  than  to  assigned  a  are assigned Hardware  resources  operation.  as  and work  and  Resources  c a n be c a n be  of i t s duration.  CURRENT PRACTICE AND RESOURCE ASSIGNMENT  systems  allocation  available fail  of  problems  with  construction  to assist  because  process  (1)  special  construction  Currently  be  as  workers.  t o an o p e r a t i o n f o r p a r t  6.3.3.4.1  can  resources  as i n d i v i d u a l  are considered  assigned  and  Labour  of their  labour  decision inability  assignment.  the current  modeling makers  i n  resource  to reflect  the actual  following  additional  The  practice  techniques  of resource  assignment  identified:  In the traditional  approach  to construction planning,  durations  assigned  to construction activities  for  a  aref i r s t  CPM  analysis,  consistent analysis. manually  with These from  productivity cycle  time"  backward the  resource  data. i spart  to  resources  durations  quantity  resources  assist  these  planning,  construction  and then  Their  are assigned  t o permit  requirements take-off  of the process  and  t o meet often  modeling  i n t h ebackward  i t .  techniques planning  Currently and systems  process.  standard a  "target  identified  i . e . s e tt h ed u r a t i o n , then achieve  resource  are calculated  data  estimation  a  as  allocate available fail  to  117 (2)  In adopting systems,  c u r r e n t l y a v a i l a b l e modeling techniques  labour  individual general  workers;  labourer  formwork. No groups  to  proper  to  have  be  4  to  be In  to  to  Once  crews  the  as  reality, out  are  f o r extended p e r i o d s  of  Currently and  available  systems  also  fail  assignment process assigned  to an  practice,  construction to  because they  operation  certain  only  for  the  crane may  hours  during  the  formwork d i s m a n t l i n g problem  is  operations of  the  operation. of  by such  operations  difficult  operation.  process, defined  resource to be  employed of  by  In a  i t s duration;  required  for  only  hour  duration  of  the  treat  this  into  sub-  One  way  to  operation can  instead however,  and  to comprehend.  techniques  be  an  resources  sub-operations The  temporarily.  actual  f o r part  eight  decomposing that  the  are  operation  two  members  f o r i t s complete d u r a t i o n .  resources  tower  of  r e q u i r e resources  construction example,  sets  their  modeling  reflect  are  time except when  c o n d i t i o n s r e g u i r e some crews to be s p l i t (3)  from  crews  certain  formed,  labour  unit  labour  1  slab  to  a  as  and  install  i s given  tracked  carry  assigned  carpenters  identification  them  be  assigned  assigned  work together  to  example,  operation.  and  operations.  for  could  allow  operation formed  resources  and  be of  assigned the  increases  make the  network  to  one  complete the  number  logic  more  118  In will  the following  t h e problems  identified  be t r e a t e d .  6.3.3.4.2 In  ALB AND  5,  the total  balance  cannot  construction  i s used  pool  usually  be  balance, might  to assist  the objective to  achieved even  i n  i n  i t serves  than  i t indicates s t i l l  as  the  be f e a s i b l e .  as design  further This  planning  perfect dynamic  t h e more a  static  goal  and  solution.  the estimated  that  i n t h e backward  described i n  reguired. Although  and  are required  REQUIREMENTS  procedure  i n f o r m u l a t i n g an e f f e c t i v e  design  used  resource  environment,  resources  perfect  OF RESOURCE  balancing  environment,  manufacturing benchmark  line  "perfect-balance"  estimate  more  ESTIMATION  t h e assembly  chapter  the  subsections,  values  When under  improvement  principle process  a  will  to be  of resource  ass i gnment. Figure be  used  work Using  6.10(a)  shows  i n the activity  category  group  the dimensions  components  from  the  production  unit  technologies,  By  the total  time,  input  decision  of t h e a c t i v i t y of  rates  trade  t h e numbers  the  to construct  o f men  category  process, selected  required  and u s i n g production  the total  man-hour  t h e assembly  requirements  The  identified.  and work  can calculate  man-hour  that can  system.  i s first  definition of  format  support  subassemblies  t h e computer f o r each  cycle  design  t h e problem  requirements dividing  a computer  unit.  by t h e t a r g e t  f o r each  trade can  119 be  calculated.  user In  These  to reflect  shown,  Concrete  operations  work  in a  normally  the total category  typical  performed  by  The numbers  are  rounded  and a r e used  the  structure  labour  the  be  cycle.  o f men  used  be  by t h e  quantified.  requirements f o r  structure  general required  The g o a l  tuned  which  include a l l cycle  that  are  contractor,  f o r each  a s t h e maximum  construction  resources  cannot  group,  the  fine  resource  high-rise  calculated.  balance  can then  c o n s i d e r a t i o n s which  t h e example  the  number  are  labour  resource  type  levels f o r  f o r t h e management i s t h e n  operations  such, that  by t h e o p e r a t i o n s w i l l  to  the  total  be b e l o w  these  levels. Special  resources  prefabrication complete  maximum of  a  of p e r f e c t  resource  personal  levels  input  resources  figure,  [Cost/Unit]  resource  per time  solution; available.  is  shown  in  figure  the cost  and i s used  [Max. U n i t ]  maker must  the  useh i s  to assign the An  example  maximum  levels  6.10(b).  In  f o r employing  i n cost  indicates  f o r the  to estimate the  and hardware.  f o r assigning  and  Consequently,  h i s experience  equipment  crane  active  be used  The d e c i s i o n  indicates  unit  tower  necessarily  cannot  on  format  a  duration.  balance  of major  special  units  cycle  o r draw  as  not  requirements.  judgment  computer  design  are  construction  assumption total  areas  such  analysis  t h e maximum  of this the  of the  number o f  120 Figure  6.10(a):  Estimate  and  assign  Estimate by Work Category-Group : Select Work Category-Group : CIVIL/SITE  Yes  /  pool  No  CONCRETE  CONCRETE (Carpenter!  (Masonry!  ( S t e e l Wkrl  (Gen.  240  Formwork Rebar Pour Ing Finishing Total  labour  20 10 80 8  160  :  20  80 112  260  192  Enter Desired Cycle Time :  (  35)  160  HOURS  Estimated Resource Requirements (If  /  perfectly  7.4  Labrl  118  <Mn-Hr>  3.4  <Man>  4 1  <Man>  DAYS balanced)  5.5  4.6  Enter Resource Pool [ 8 1  1 6 1  Enter Special Resource Pool :  Figure  6.10(b):  Assign special  ' Ye$  /  (  5  J  t  No  resource  pool  SPECIAL RESOURCE POOL : II.D.l Tcrane CncrPmp SlbFm ClmnFm ZonSI ZonW2  [Type! Equipment Equipment Hardware Hardware WorkZone WorkZone  Figure  [Description]  [Cost/Unltl  Tower Crane Concrete Pump EFCO Floating Slab Form EFCO Modular Column Form Storage Yard Zone 1 Active Work Zone 2  6.10:  Estimate  $1000.00 $125.25 $750.00 $375.00  and a s s i g n  / / / /  Day Hour Week Week  resource  [Max.  Units! 1 1 10 9 1 1  pools  121 6.3.3.4.3  ASSIGNING  Figures can  be  the  list  to  6.11(a)  assigned  the  resource  After  resources  required  specified  t h e work  calculated  performed  by  each  and  assignment  the as  crew  study.  assigned  Operations same  construction  of  operation  For  this  two  o r more  a r e then as  the  a  the  formed,  the By  identified  the based  selected  using  the  guideline,  and  identifying  the  sequence  of  operations  for productivity  cases  in  resource  formwork slab  As  c a n be  within  crew  formwork building  operation  i n time  example,  t h e management  operations.  labour  t h e computer and  the  note:  of i n s t a l l i n g  case,  within  followings  for  of i n s t a l l i n g  the  operation by  for  enter  the  t h a t do n o t o v e r l a p  cycle,  to  the  t o more t h a n one  crew;  selected  principle  operation.  c a n be The  been  the operation  crews,  6.11(a),  and d i s p l a y e d  prompted  calculated  Crews  resources  ALB  requirements  are worthy  Crews  the  of  perform  resource  operation  c a n be  labour  In figure  has  i s  perform  technology.  to  user  Using  how  are retrieved  operation  the  assignment  committed  the  an  resource  assigned  by  manner.  to  duration  construction  (1)  realistic  assignment, duration.  control  show  operations  operation  on  and 6.11(b)  in a  of defined user.  LABOUR CREWS  a  can  performed five  day  perform  the  on one d a y a n d core  can assign  operations  formwork t h e same  that  share  perform  on  next.  crew  to  t h e same  122 crew  cannot  overlap  finish-to-start  (2)  in  time,  The  term  mixed  crew  more  than  one  labour  figure  6.11,  labourer  idle can  this  more  mixed  duration  would  than  assign  time.  a  50%  a crew  and  a  crew  of  one.  The  use  general  more  [Duration, Duration only  the  labour  to  the second  problem  will  be  specified  duration; employed  operation;  examples  of  as  assignment be  1  up in  general  will  problem,  a  labour  for  each crew  of time  time  are described  the  of the  procedure to  approach  resources  t o be  attributes  of  assignment.  i s t o be  when  the start  i n t h e next  then  another  employed  or percentage  from  one  multiple-crew  crew  time  be  operation  f o r 50%  assigned  additional  lag indicates  i n terms  made  labour  this  labourer  the assigned period  and  i n the t r a d i t i o n a l  the  defined  indicates that  operation  having  shown  f o r the complete  and t o a l l o w  effectively, are  solve  identified  needed.  example  general  To  general be  the  a crew  carpenter  the  no l o n g e r  Lag]  for this  as  t h e s l a b formwork s e c t i o n .  of  construction planning  employed  3  that  1  assignment  To s o l v e  In  of 3 carpenters  then  when  of  of the time.  can  operation  types.  mean  case  the  to describe  to install  This  allows  treated  Crews  i s used  crew  c a n be f o r m e d  However,  are  r e l a t i o n s h i p s i n the network a n a l y s i s .  Mixed Crew and M u l t i p l e  of  to  they  of the  the  crew  of the  section.  123 6.3.3.4.4  ASSIGNING SPECIAL  Figures formats  6.12(a)  for  operations.  and  assigning A list  RESOORCES  6.12(b)  special  show  resources  of the s p e c i a l  resource  can be r e t r i e v e d and the corresponding the  specified  operation.  6.12(a), the tower crane InsSlbFm-l  after  For  the  to  i s to be employed  input  construction  type  identified  resources  the example  20% of the o p e r a t i o n  computer  assigned to  shown  in figure  i n the o p e r a t i o n  i s completed and f o r  40% of the t o t a l o p e r a t i o n d u r a t i o n . In the example shown i n figure  6.12(b), ten u n i t s  formwork)  are  operation  InsSlbFm-l.  the o p e r a t i o n  of the hardware SlbFm  available, five The  duration.  units  resource  are  (EFCO  assigned  i s employed  to  slab the  f o r 100% of  124 Figure  6.11(a):  Select  operation  to  assign resources  CREW and SPECIAL RESOURCE ASSIGNMENT Select from operation l i s t : 11.D.l  [Description!  ir»sF«iSlb-1  Install Slab Formwork BAY<A1,A2,B1,B2 C1>  2  RbSlb-1  Rebar Slab BAY<A1,A2,B1,B2,C1>  3  SlvSlb-l  Mechanical Sleevings BAY<A1,A2,B1,B2,C1>  4  CncrSlb-1  Pour Concrete Slab BAY<A1,A2,B1,B2,C1>  5  CureSIb-1  Cure Concrete Slab BAY<A1,A2,B1,B2,C1>  6  DsmFmSIb-1  Dismantle Slab Formwork BAY<A1,A2,B1,B2,C1>  INol 1  Figure  InsSlbFm-l  I  6.11(b):  Operation : Install  Assign  f  labour  InsSlbFm-l  crew  to  meet  target  Min. Crew Size :  operation  3  Neglect :  S l a b Formwork BAY<A1,A2.B1,B2,C1,C2>  RESOURCE POOL :  [Carpenter]  [Masonry!  Total : Balance :  8 ' 5  6  duration  No / Yes 2 480 M  Content :  ( S t e e l Wkr! 5  [Gen. L a b r l 4  <Man>  CREW FORMED : SlbFrmCrw-1 SIbRbCrw-l  3  Enter Desired Operation Duration :  [  7 1  HOURS / DAYS  Estimated Resource Requirements : 2.5  0.5  <Man>  ASSIGN CREW : ( SlbFmCrw-1 ! Enter IDuratlon;Lag! ADD ANOTHER CREW :  3  I  <$duratlon or hr:mln> : /  Yes  ASSIGN SPECIAL RESOURCES :  No  Figure  6.11:  No  I 100*;0 ]  / 'Yes '  Assigning  labour  crews  to  operations  Figure  6.12(a):  Operation Install  Select  :  special  resource  type  to  assign  InsSlbFm-1  S l a b Formwork  BAY<AI,A2,B1,B2,C1,C2>  ASSIGN SPECIAL RESOURCES : EQUIPMENT  HARDWARE  Select EQUIPMENT from l i s t  :  [I.D.J  (Description)  TCrano  Tower Crane  WORK-ZONE  TCrano (Cost/UnltJ  6.12(b):  Operation Install  :  Assign  [  special  No  1  1 J  <ifdurotlon or hr:mln> :  ASSIGN ANOTHER SPECIAL RESOURCE :  Figure  UnltsJ  $1000.00 / Day  Enter No. of Units to be Assigned : Enter [Duratlon;Lagl  [Max.  /  ( 20Jf;40£ 1 J  resources  to  operation  InsSlbFm-1  S l a b Formwork  BAY<A1,A2,B1,B2,C1,C2>  ASSIGN SPECIAL RESOURCES : EQUIPMENT  HARDWARE  Select HARDWARE from l i s t  :  WORK-ZONE  SlbFm  II.D. 1  (Description)  SlbFm  EFCO Floating Slab Form  $750.00 / Week  ClmnFm  EFCO Modular Column Form  $375.00 / Week  (Cost/Unl+1  Enter No. of Units to be Assigned : Enter (DuratIon;Lagl  Figure  6.12:  Assigning  Unltsl 10  [ 5 1 [ 100*;0 )  <$durat!on or hr:mln> :  ASSIGN ANOTHER SPECIAL RESOURCE :  [Max.  fNo"| /  special  Yes  resources  to  operations  126  6.3.4  As the  mentioned  computer  system  and  described  6.2, t h e r e l a t i o n s h i p maker  i n a  as s y m b i o t i c .  the decision  the description  activity  design,  environment design  maker  In other  depend  between  decision  on  support  words, t h e  each  of the d e c i s i o n support  t h e computer  i n which  solution  function  i n  schedule.  by  a  resources  must  resources  must  other  to  to provide  can formulate  manner.  Another  the design  i n order  produce  between  to  operations  i n  an a  major solution  an  overall  using  shared  and t h e e f f e c t i v e n e s s i n using  determined.  be communicated  system f o r  i s t o analyze  be i d e n t i f i e d be  personnel  realistic  the user  Conflicts  functions mainly  management  of t h e computer  formulated  and  i n section  ANALYSIS  a problem. In  must  4 - SOLUTION  and t h e d e c i s i o n  c a n be  computer solve  MODULE  Findings  t o t h e user  from  the analysis  f o rpossible modification  improvement.  6.3.4.1  CURRENT AND  PRACTICE  CYCLE  Traditionally, resource usage. usage  profiles If a  resource  exceeds  ANALYSIS  DESIGN  resources  are assigned  a r e produced  t o study  resource  fluctuates  IN RESOURCE  profile  t o o much the  indicates  or that maximum  t o a c t i v i t i e s and  the labour that  the  t h e maximum level  resource resource  level  available,  of a then  127 management  must  make  the appropriate  decisions  to solve the  problem. Some  problems  levelling  floats  resource  design  to achieve  usage,  goal  balanced floats  between  the  usefulness  construction resource resolve  constrained conflicts  achieved  by  operations;  of  continuity  not considered  a  i s to achieve  a  i s to eliminate a l l  can progress  for  shared  might  resources,  and  designing  the goal  While  a  able  to  be  i t is  delaying  so, i t defeats  also  constant.  questionable.  algorithm  smoothly  design  remains  levelling  scheduling  interrupting  cycle  will  therefore  i n using  i n doing  they  level  resource is  design  uninterrupted  resources  cycles  use  on t h e u s e o f  objectives -  the goal  so t h a t  An  of  rely  i s generally  words,  operations  that  the  algorithms.  In other  interruption.  indicates  specified  however,  through  which  i n construction cycle  cycle.  without  resolved  algorithms  o b j e c t i v e by most  The  The  be  and a l l o c a t i o n  activity of  can  only  construction of a  balanced  cycle. At  present,  that  a  balanced  user  must  there  i s no  cycle  design  depends  intuition,  on  assisted  by  cycle  analysis  the formats  are  described  can  be  h i s experience,  satisfactory and  algorithm  the  design.  i n sections  can  obtained. personal  computer,  The  that  results  The  system  judgment  to of  guarantee  formulate the  i n which  they  could  6.3.4.2  and  6.3.4.3  be  and a  solution presented  below.  How  128 these cycle  results design  6.3.4.2 Of five, can  c a n be used i sdiscussed  of  the  CRITICAL PATH METHOD FOR SOLUTION ANALYSIS the analytical  t h ec r i t i c a l perform  models  path  the required  deterministic  mathematical  t o perform  required  require  effort  analysis  programming  event  the required  f o r day-to-day  software  require  simulation  also  and provide t h e excessive  use i nthe f i e l d  t o reside  and  techniques could  both  that  the least  simulation  analysis  However,  four and  method  and requires  programming  sophisticated  i nchapters  i sthe simplest  Discrete  information.  programming  reviewed  method  effort.  used  t h e balance  6.3.5.  i nsection  programming  be  t o improve  and  and both  mathematical  i n the decision  support  system. In has  addition  toi t s simplicity,  t h eadvantage  of having  industry  f o ran extended  concepts  a r e comprehensible  The  critical  appropriate  path  construction additional will  period  tool  computer  n o t be t r e a t e d  as  routines i nthis  path  method  i n the construction  o f time  and the underlying  management p e r s o n n e l .  i s therefore  adopted  as an  for thedecision  support  system.  o f t h e need  cycles,  used  t oproject  method  analytical  However, because  been  thecritical  t o consider stated might thesis.  i n  the overlapping of section  be needed. T h e s e  6.3.3.3, routines  129 6.3.4.3  PRESENTATION  After results  the tentative  have  refinement  can take (1)  committed  crews  path  formats.  charts.  PATH  (EST),  Current  late  late  finish  been  types  analysis (3) w o r k  ANALYSIS  analysis  analyzed,  so that  of  the  solution  output  c a n be  results,  (2) s t a t u s  schedules  f o r labour  start  RESULTS  results  practice  The a c t i v i t y  time  has  resources.  CRITICAL  Critical  and  RESULTS  t o t h e user  Three  path  resources,  6.3.4.3.1  bar  solution  place.  critical  and s p e c i a l  several  ANALYSIS  t o be c o m m u n i c a t e d  identified: of  OF  can  uses  be  presented  tabular  information includes:  time  time  (LFT),  6.13  represent  (LST),  free  early  float  outputs early  finish  (FF) and  in and  start  time  (EFT),  total  float  (TF) . Figure critical  path  planning  at the production  in  hours  assist  analysis  and minutes.  the user  identified (1)  results  Two  of  the formats  c a n be p r e s e n t e d .  level  requires  attributes  i n the design  in  time  that  improvement  Activity  units  c a n be  process  which  t o be  used  have  to been  i n the table: [FF/Duratn]  operation that  one  However,  the  ratio  duration. I t indicates  t h e crew  presuming  -  assigned  free  float  to the  the percentage  of time  to the operation w i l l  a l l operations start unavailability  of  at their  of resources  be  earliest  may  idle, time.  preclude the  130 early  start  impose  o f an o p e r a t i o n . Crew a s s i g n m e n t s  additional  network  logic  operations  constraints  - having  imposes  a  on  t h e same  the  crew  therefore  critical  assigned  finish-to-start  path t o two  relation  between  them. (2)  [LbrCost/Duratn] the  operation  rough by  estimate  which  shorten.  The e x a c t  6.3.4.3.2  type.  order  has  shows  of s p e c i a l c a n be  represented  identify  problem  The  [Active  the  resources  prefabrication  tedious. summary  resources  -  of  be  a  saved  this  ratio  will  cost  may less  or cost,  help to  however,  the objective.  RESOURCES i n resource  the profiles  of resource  how  could  to achieve  a l l conflicts  t o study  c a n become  table,  areas,  of saving  chosen  to identify  t h e number  process  usage  cost  operation  amount  cost  o f a n o p e r a t i o n . When t h e  S T A T U S OF COMMITTED  When  status  labour  time  critical  on t h e method  normally  this  the idle  labour  duration. I t provides  d u r a t i o n h a s t o be s h o r t e n e d ,  depends  one  o f how m u c h  indicate  In  of t o t a l  to the operation  eliminating  cycle  - the ratio  types  of  assigned  Figure  resource i s large,  6.14, t h e r e s o u r c e  information  equipment,  i n tabular  each  usage,  regarding the  hardware  form  which  and  work  can  help  areas. Time] are  area,  and [%Idle] being  labelled  indicate  used. PfZone-Al,  For  how  effectively  example,  i s occupied  the f o r 27  131  hours  and i s unoccupied  hours  cycle.  identified listed  Conflicts  i n using  and the o p e r a t i o n s  t o guide  example  the user  shown,  start  of  between  again  i n using  chart  described  with  cycle),  InsSlbFm-3 i s  f o r the tower  s e c t i o n , can help  WORK S C H E D U L E S FOR LABOUR  order cycle.  than  the c o n s t r u c t i o n  In the DSS  developed,  labour  as i n d i v i d u a l  (M.O.T.)  chart  multiple  activity  adapted  to p r o v i d e  special  resources.  activity  management  solutions.  CREWS AND  need d e t a i l e d t a c t i c a l  labour crews and to schedule  to perform  This  RESOURCES  F i e l d management personnel to d i r e c t  crane.  use of the m u l t i p l e  i n the next  SPECIAL  crane a r e  the o p e r a t i o n s  i d e n t i f y q u i c k l y the problems and a l t e r n a t i v e  6.3.4.3.3  the  hours are measured  the o p e r a t i o n  RbrClm-S2  together  In  r e q u i r e the use of the tower  17:00 - 18:00, with  can a l s o be  the tower  - 16:00 (working  the c o n s t r u c t i o n  competing  information,  the resource  35  that a r e competing f o r i t a r e  RbrClm-Sl and InsSlbFm-3 both crane;  (or 24%) of the  in resolving conflicts.  conflicts  i n d i c a t e d ; between 15:00 from  f o r 8 hours  special  resources i n  operations  f o r a given  f o r construction  resources workers.  shown  chart  work  design  as crews  The m u l t i p l e  i n section schedules  being rather  operation  6.16 i l l u s t r a t e s  described  detailed  cycle  a r e assigned  in figure  plans  time  how the  4.1 can be  f o r crews and  132 The  multiple  introduced and  i nindustrial  for studying  production  sequences each  planning  and  i s  i t has been  no  therefore  improving  t h e balance  o f work  conflicts  i n t h e usage  of shared  The  M.O.T.  analysis finish  work  results.  time  perform  chart  i t . Thus,  schedule  operations  a r e shown a s i d l e  to the in  or  f o rs p e c i a l  indicate coffee given using  areas.  example, shared  How  improvement To crews which  time  f o r studying  and  and i n r e s o l v i n g  from  thecritical  that  i s assigned represents  crew of  (IDLE f o r Breaks  chart  or  the study resources,  the selected  crews  be  i nsection  and s p e c i a l  special  be shown  n o t shown i n  crane  used  conflicts and work  for  design  6.3.5.  o f i n t e r a c t i o n s between t h e user  a  crews and  can also  Although  to  construction  labour  as t h e tower can  path  by i t s s t a r t and  labour  times.  such  be d i s c u s s e d  facilitate  and s p e c i a l  crew  i t i salso possible to indicate  t h e M.O.T. will  side  balance  resources).  resources,  i n  along  i splotted  imperfect  and lunch  Woodhead  resources.  f o rthe corresponding  Floats,  i nthe  and  i n t h e M.O.T. c h a r t  resource.  AVAILABLE  useful  (or crews)  a column  i n assembly  I t c a n show t h e  by each  c a n be d e r i v e d  t h e crew  studies  application  assignments  An o p e r a t i o n  under  (Halpin  described.  performed  technigue  mentioned  computerized  has been  of operations  other  assignments  literature  [91]),  modeling  f o r work method  o f work  Although  Nicholis  i s a  engineering  management  construction  chart  the balance  lines.  construction [43],  activity  can enter resources  labour  theorder i n a r e t o be  133 reported,  as  schedules  for  side can other  by be  side  shown two  operations.  work  figure areas  to determine  eliminated  work  in  area,  by  6.15. can  whether  assigning  o r by c h a n g i n g  For be  example,  selected  overcrowding  certain  for  of  work  display  i n one  operations  the sequence  the  to  area the  construction  * *  C R I T I C A L  A c t i v i t y Duration:  Operation  A N A L Y S I S  R E S U L T S  * *  36:30  EST  1.0.  P A T H  LST  EFT  LST  FF  Duratn  FF Dura+n  Lbr Cos1 Duratn  InsSlbFm-l  ( E l e v . 4)  0:00  0:00  7:00  7:00  00:00  7:00  0.00  $112.50  lnsSlbFm-2  ( E l e v . 4)  7:00  7:00  14:00  14:00  00:00  7:00  0.00  $112.50  lnsSlbFm-3  ( E l e v . 4)  14:00  14:00  21:00  21:00  0:00  7:00  0.00  $112.50  RbrCw-1  (Elev.  5)  24:00  24:00  28:00  28:00  00:00  4:00  0.00  $  87.50  RbrCw-2  (Elev.  5)  28:00  25:00  33:00  35:00  2:00  5:00  0.40  $  87.50  * • • •  « • • •  F i g u r e 6.13:  C r i t i c a l path  analysis results  • • • «  13  SPECIAL  RESOURCE  C y c l e Time  Resource  :  I.D.  STATUS  35:00  Active  *ldle  Time xx:xx  x.xx  PfZone-A1  27:00  0.24  PfZone-A2  30:00  0.15  WrkZon-E3  35:00  0.00  TCrane  Max Avail  Max. Used  ConfI l e t s :  15:00 - 16:00  RbrClm-Sl;  17:00 - 18:00  InsSlbFm-3;  Figure 6.14:  InsSlbFm-3 RbrClm-S2  Resource  Status  Table  MULTIPLE OPERATION TIME CHART :  Report to  :  Screen / P r i n t e r  Report ALL Crews/Resources :  Yes / No  Select Crews/Resources to Report :  Crew/1  Crew/2  Crew/3  Crew/4  Crew/5  Crew/6  Crew/7  Crew/8  FmCrw#1  FmCrw#2  RbrCrw#1  RbrCrw#2  CnCrCrw/1  TCrane  GenLbr#1  PfZon#1  Crew/Resource I.D.  Description  FmCrw#1 FnCrw#2  Formwork crew /I, 6 carpenters, 1 general labour Formwork crew #2, 5 carpenters  CnCrCrw#2  Concrete finishing and clean-up crew, 3 masons, 1 general labour  igure  6.15:  Select  crews and s p e c i a l r e s o u r c e s  to report  i n M.O.T. cha  M U L T I P L E  ACT'V  ACT' L  TIME  TIME  0:00  7:00  111 FuCrw/l  O P E R A T I O N  121 FnCr«/2  131 RbrCrw/l  141 RbrCrw/2  T I M E  Cncr/1  CH  A R T  151 161 TCrone  171  181  GonLbr/l  PfZon/l  Day 1  7:30 8:00  iiaatBtoiaa  Q j/nS | b,FjH~ 1 (Elev.  3)  8:30  InsSlbFm-1 ( E l e v . 4)  aaamam*.amjtm  l a a a i u i i i t i a  PfCwRbr-1 ( E l e v . 5)  PfClmRbr-Sl ( E l e v . 5)  itaBiadaio  AVAILABLE  I OLE PfClnrtbr-SI  PrClms ( E l e v . 5)  9:00  InsSlbFm-1  9:30 10:00 10:30 11:00 II : 3 0 12:00 12:30 1:00 1:30  cIis«Diaiai  Clean-Up  AVAILABLE  Elev. 3  DsmSIbFm-2 x x x x x x  x x x x x x  ( E l e v . 3)  2:00  x x x x x x  x x x x x x  PfCwRbr-2  PfClmRbr-S2  (Elev.  (Elev.5)  5)  x x x x x x  i,  x x x x x x  x x x x x x IDLE  2:30  InsSlb-Fm-  3:00 7:00  3:30  7:00  7:00  x x x x x x PfClmRbr-S2  V as -« -*a* • a •  .Y._.  a  Day 2  7:30  DsmS I bFm-2  «••..««.«.  (Elev.  lnsSlbFm-2  RbrSlb-1  (Elev.  ( E l e v . 4)  3)  8:00  4)  PfClmRbr-S2 (Elev.5)  AVAILABLE  PfClmRbr-S3  9:00  ( E l e v . 5)  IOLE  L  10:00 10:30 11:00  12:30 1:00  AVAILABLE DsmSlbFm-3 x x x x x x  x x x x x x  x x x x x x  x x x x x x  x x x x x x  x x x x x x  x x x x x x  ( E l e v . 3)  1:30 2:00  Y.........  2:30 3:00 14:00  3:30  14:00  7:00  V  lnsSlbfM-2  IDLE  Y  Day 3  7:30 8:00  Q$jnS I b F l B 3  Ba>oBBBa»a««  (Elev.  lnsSIFm-3 ( E l e v . 4)  -  3)  8:30  laniaiiiDii  RbrSlb-2 ( E l e v . 4)  ••aaaistmii  RbrClm-Sl ( E l e v . 3)  mammmmmaaa PrSlb-1 ( E l e v . 4)  9:00  RbrClm-Sl  PrSIb  1..  IDLE  InsSlbFm-3  9:30 10:00 10:30 11:00 11:30 12:00 12:30 1:00 1:30 2:00 2:30 3:00 21:00  3:30  21:00  7:00  V  1  DsmClmFm-SI x x x x x x  i.  x x x x x x  x x x x x x  (Elev. 3)  1131  x x x x x x  x x x x x x  RbrClm-S2  R*br( brClm-S2 I x x x x x x< x  i........  ( E l e v . 5) InsClmFm-SI  x x x x x x DsmClmFm-SI  AVAILABLE  ( E l e v . 5)  InsSlbFm-3  Y  V  JL.......  Day 4  7:30 8:00 8:30  Eaaansaaaaa sans•anasue  a n a a i a i a a a i  isasaaasaaB  InsCwFm-l  RbrSlb-3  RbrClm-S3  PrSlb-2  (Elev.  (Elev.  (Elev.  (Elev. 4)  5)  4)  5)  RbrClm-S3  PrSlb-2  lnsC*Fm-l IDLE  9:00 9:30 10:00  DsraClmFm-S2 ( E l e v . 3)  10:30 11:00  InsCImFm-S3  11:30 12:00 12:30 1:00  x x x x x x  x x x x x x  x x x x x x  O.T.  3:30 4:00  RbrCw-1  ( E l e v . 3)  ( E l e v . 5)  x x x x x x  x x x x x x IDLE  Bsasaasaaaa AVAILABLE  BRbrCw-1 iBasaaaaa (Elev. 5)  Y  5:00 Day  x x x x x x lnsCwFm-2  v  i l a i s a i s a a a  4:30  DsmClmFm-S2  as.sssaVBaa  InsCwFm-2  V  3:00  BEsaasaaaaa  i  2:00 2:30  assasaaiDii  AVAILABLE x x x x x x  ( E l e v . 5)  1:30  28:00  3 28:00  7:00 7:30 8:00  sat a a at teat at * as  DsmClmFm-S3 ( E l e v . 3)  aacssBBBis:  caasaaBSBaa  aaaBiassaoa  ClsCwFm-1  RbrCw-2  RbrCw-2  PrSlb-3  (Elev.  (Elev.  BE a  5)  5)  (Elev.  5)  AVAIL ABLE  <aa PrSlb-3  (Elev. 4)  9:00  lnsClmFm-S3  CIsCwFm-1 ...........  9:30  (Elev. 3)  AVAILABLE  8:30  i, DsmClmFm-S3 ^  10:00 IDLE  10:30 11:00  essaaaaBBBB  II : 3 0  ClsCwFm-2  12:00 12:30  x x x x x x  1:00  x x x x x x ( E l e v . 5)  y  aoisaaaaaDi  Y  ClsCwFm-2  x a xa sxs cxa axa ax a a  x sxSBx3 statist x x x a  IDLE  IDLE  x x x x x x  x x x x x x  x x x x x x  AVAILABLE  1:30 2:00  DsroSlbFm-l  2:30  ( E l e v . 4)  3:00 35:00  Y  PiClmRbr-S3  lnsSlbFm-2  9:30  12:00  PrCrWIs  ( E l e v . 5)  8:30  11:30  PfClmf)br-S2  PrCrWIs  3:30  Figure  1  6.16:  Y  Multiple  Operation  Time  (M.O.T.)  Chart  x x x x x x  138  6.3.5  MODULE  6.3.5.1  DIFFICULTIES  A balanced design  important balanced design  y e t most  parameters  linkages  linkages,  eliminate  changing  conflicts  and f i n i s h  might  be a f f e c t e d  operations  variables  to  that  process  i n designing  t o each  of a  shared  and could  cause  of the variable  cycle  design.  operation  resource,  of the successors  other but  design  t o an  a  three, the  Because  on t h e o v e r a l l  a  i s t h e most  i nchapter  over-time  to  to  the start  to the operation  conflicts  between  other  resources.  the complexity  c a n be m o d i f i e d  i s t h e number to solve a given  example,  conflicts  i n  of  design  problem (see using  shared  c a n be e l i m i n a t e d b y :  assigning the  times  6.3). For  resources  effect  be m o d i f i e d  precisely.  the value  DESIGN  e f f e c t i v e n e s s of  process  As s t a t e d  i n using  f o r shared  Adding  (1)  complex  i n assigning  times  figure  improvement  be d e f i n e d  have a s i g n i f i c a n t  ENRICHMENT  i nthe i n i t i a l  must  and v a r i a b l e s a r e l i n k e d  cannot  example,  solution  and t o improve  construction cycle.  complex  For  i snot usually achieved  The d e s i g n  and  AND  IN IMPROVING AN A C T I V I T Y  conflicts  usage.  IMPROVEMENT  The i n i t i a l  resource  resource  could  cycle  solution.  resolve  the  5 - DESIGN  over-time  operations  or extra  competing  shifts  t o one o r more o f  f o r t h eshared  resource;  139 (2)  speeding that  the  earlier  (3)  up  an  operation  can  changing  the  use  the  construction  operations.  For  for  pouring  concrete  for  other operations;  a combination  Each  feasible  order  increasing  to  example,  of  the  course select  of  in  order  above  must of  The  latter  by  [131]  the  requirement  and  nature  required.  obtained an  a A  of  at  an  be  one  or  more  could  be  used  the  tower  carefully  seriously  which  the  has  of  considered  i s most  upset  concern  crane  action.  been  cost  original identified  "stability  been d i s c u s s e d i n s e c t i o n  of  the  by  activity  design  mathematical  tria1-and-error manual  obtained  is  computer  environment  identify  has  solvable  Consequently,  solution  so  in  re-  4.5.  AN APPROACH TO SOLUTION IMPROVEMENT  realistic,  is  as  of  action  schedule.  The  resource  free  courses  course not  to  operations  6.3.5.2  crew s i z e  c o n c r e t e pump  action  the  does  a  and  scheduling"  shared  technology  effective  Willis  the  time;  (4)  in  o p e r a t i o n by  which  problems,  tends  general  routines. uses  suggest  programming  approach  process in  problem  So  the  to  less the  to be  precludes  formulation.  problem tedious  accurate  g o a l becomes  power  solutions,  of  a  solving and  than  the that  to create  the  computer  analyze  them,  to and  140 incorporate user  the  and  analyze  The  critical  and  the  6.13  conflicts  P-Matrix, impact  user  an  computer (see  of  Figure  analysis design  is  to and  the this  M.O.T.  has  steps action  of  can  be  the  been  a  list  The the  is  shown used  and  chart  of  to  the  into  identify  with  the  cycle  the  possible design.  for modification,  possible  of  guide  the  can  solution  formulation is  then  courses  computer  repeated  figure  competing  together  chosen of  in  the  overall  selected. This  process  intuition  as  insights  a c t i o n on  6.17).  achieved.  table  gain  suggest  results  resources  the  operation  to p a r t i c u l a r  according  status  can  and  improvements.  shared  user  can  judgment  analysis  studying  a course  After  action  path  using  By the  of  potential  resource  in  operations.  the  experience,  then  until  a  process  followed  by  satisfactory  141  Modify Operation  :  RbRCw-2 (Elev.  1.  R e - D e f i no L a b o u r  2.  Re-Schedule Operations  3.  Re-AssIgn Resources  4.  Assign Over-Time  5.  Add Extra  6.  Change Production Technology  7.  Prefabricate Components  6.17:  General  Crew  Shift  Select Action to Take :  Figure  5)  rules  1 1 1  f o rdesign  improvement  142  6.3.5.3  SOLUTION ENRICHMENT AND THE M.O.T. CHART  Any  model  of  simplification  a  of  problem reality.  environment  being  on  theproblem  modeling  realistic treated.  (1)  manner, Examples  Examples such  although  elements  and to  are  include and  must  For  example,  not  well  not  timbers,  i t s design.  h a s been p u t i n t h e most been  of stock  general  However,  materials  clean-up  of these  these  and cannot of rebar  and organized, and formwork  i n a  scheduled.  and  smaller  i n the cycle planning  i fthe inventory  the reinforcing  have  operations  normally  Inclusion  be p e r f o r m e d  maintained  design  and Operations  delivery  operations  a  are:  and i n f r e q u e n t  of equipment.  complicate  activity  emphasis  Work T a s k s  project  non-regular  operations  of  tasks  rebar  maintenance  the  and t h e d e c i s i o n process  of these  of these  as  i s necessarily  n o t a l l of t h e p r o j e c t elements  work  construction  For  developed,  Inclusion of Infrequent Many  situation  tends  work  tasks and  be  neglected.  and timbers a r e  the productivities  crew  c a n be  adversely  affected.  (2)  Assigning Different An  additional  conflicts  Breaks tool  i n t h e usage  to Different  for  field  of  Crews  management  shared  t o remove  resources  i s by  143 assigning If  managed  idle  (3)  breaks  time  carefully  construction an  design  can  assigned  labourer simply  6.3.5.4  To  to  considered  allowed realistic  that  Operations and systems f o r  resources  study  t o be  assigned  duration.  In the  herein,  resources  f o r part  of  o f t h e M.O.T.  assign  an  t o reduce  i t s  chart,  idle  general  the duration  critical  TO M A N I P U L A T E  thei n i t i a l  solution  operation  or  c a n be  that  CHART  and t o i n c l u d e  t h e system  t h e M.O.T.  schedule  THE M . O . T .  i n the problem  processes,  t o manipulate  chart  can  elements  d e f i n i t i o n and user  should  to obtain  be  followed  a  be more  at the  site.  Schofield instructions  operations.  proposed  to  a  at the outset  work  between  i n time.  formulation  construction  from  operation  t o ensure  improve  to eliminate  operation  decide  INSTRUCTIONS  solution  an  times.  can help  f o r i t sentire  might  completed  at different  methodologies  environment  t o an  to  require  F o r example,  management  not  planning  activity  duration.  Help  available  operation  be  transitions  of Temporary  Currently  crews  the process  and improve  Assignment  to  to different  [118] has d e s c r i b e d  t o capture  some  the use of high  of thefactors  level  and r e s t r i c t i o n s  144  that the  are "far precedence  developed of  more  diagram"  in  a t Nottingham  instructions  design  extensive  could  decision  described  just  the  be  used  are  described  Sequencing  (NULISP).  A  to  some  treat  by  Program  similar set  i n the construction  system  Here  those  Line  University  support  earlier.  than  cycle  the  elements  of  possible  examples  commands:  Commands f o r a s s i g n i n g so  as t o e l i m i n a t e  or  t o ensure  [ASSIGN]  conflicts  a smooth  [BREAK]  and removing  labour  i n using  transition  <name> TO < c r e w  crews  shared  between  breaks  resources  operations.  I . D . / A L L > FROM <hr:mn>  TO <hr:mn> [REMOVE] [MOVE]  [BREAK]  Command to  [BREAK]  <crew  conflicts  the durations  [ASSIGN]  [O.T.]  TO  I.D.> <name>  I.D.> <name> TO  f o r assigning  eliminate  crash  <crew  over-time i n using  of c r i t i c a l <crew  <hr:min>  to operations shared  i n order  resources  or to  operations.  I.D./ALL>  FROM  <hr:min>  TO  < h r : m i n> Commands operations such work,  as  for  assigning  and  or  infrequent  work  general  to idle  clean-up  resources.  and  re-assigning tasks other  and site  defined  operations, maintenance  145 [ASSIGN]  [ J O B ] <name  I.D.>  /  [JOB] <crew  Command  f o r manually  might  additional more  that  operation  without  t h e M.O.T. c h a r t ,  t h e user  This  rate  slightly  of a  particular  without  assigning  command a l l o w  t h e bypass of  processes.  <operation  Command  similar  I.D.> BY < h r : m i n . >  t o [CRASH]  theduration <operation  Command w h i c h  an  the production  resources.  [CRASH]  [STRETCH]  crashing  c a n be i n c r e a s e d  tedious  stretching  <resource  I.D.> <name / o p e r a t i o n I.D.>  i t . In reviewing  decide  operation  I.D.> TO  FOR < h r : m i n >  [REMOVE]  redefining  operation  b u t i t i s used  f o r manually  o f an o p e r a t i o n .  I.D.> BY < h r : m i n >  allows  t h e system  m a n u a l mode t o t h e s y s t e m  user  guided  mode  to return (Figure  from t h e 6.17).  [RETURN]  The the  user  intuition elements The  instructions described and to  permit  the  "enrich"  an  not considered  modified  M.O.T. c h a r t  design  above p r o v i d e  application activity  of  design  flexibility judgment by  i fr e q u i r e d ,  plotted f o ruse i n the f i e l d .  and  including  i n thesolution formulation  c a n be' r e a n a l y z e d ,  to  process. and t h e  146  7.  7.1  conceptual  activity  design  f o rthis  design  developed  thesis  personnel  repetitive  construction  provides  a planning  captures  i n  environment  a given  for  educating  management  problem  a n d document  It define  t o seek  provides a  realistic  problem manner.  system  i n which  can  reflects  that construction through,  construction  albeit  activities.  f o rfuture  management  t h e impact  an  as a  environment  and formulate  medium  define of  no s o p h i s t i c a t e d  "optimal" design  solution  reference and  can systematically  design;  The  personnel.  can function  and analyze  design  specification  realistically  go  system  personnel  on t h e a c t i v i t y  employed  level  process  c a n be u s e d  support  whereby  is  that  mentally  experienced  decision  the objective  i n theformulation of a design  situation less  system f o r  an environment  This  making  designing  captured  for  decisions  cycles.  support  s i x meets  at the production  personnel  imperfectly,  The  i nchapter  thedecision  management  information  of a decision  by p r o v i d i n g  management  and  RECOMMENDATIONS  CONCLUSIONS The  set  CONCLUSIONS AND  a  certain  algorithm  solutions.  i n which design  management  alternatives  can i n a  147  By  recording construction technologies  format,  the  different  system  user  technologies  can  compare  and s e l e c t  and  t h e most  in a  systematic  experiment  with  appropriate  ones  for construction. The of  decision  resource  process. areas  are  consideration  from  be  assigned  special  planning  analysis  i n formats,  identify  improvements  estimates  as  assignment crews;  resource  in  the  be a s s i g n e d  work  to  permit  activity  design  f o r only  part  o f an  construction  time  of  the  initial  the resource chart,  problems  with  that  design  solution  status table can  help  the design  and  and t h e  management formulate  to i t .  Instructions  c a n be u s e d  management  usually  included  produce  tactical  level.  a  can a l s o  operation  personnel  accurate  duration.  presented  multiple  can  as  site  Resources  Results are  of  provides  f o r use i n the resource  resources  treated  operation's  system  requirements  Labour  process.  support  to provide  personnel  i n the solution plans  that  can  the f l e x i b i l i t y f o r  to consider  elements  formulation process be  followed  at  the  not  and t o field  148  7.2  RECOMMENDATIONS  7.2.1  COMPUTER  This of  a  thesis  system  support has  and  personnel  fully  f o r activity  the  this  realities to  level,  design  design.  programmed  whether  i s acceptable  APPLICATION  t o the conceptual  been  to test  documentation  i ndesigning  Historical  FIELD  The  f o r computer  decision of  support  construction  construction  management  a prototype  system  must  and tested.  On-site involved  AND  system  at the production  developed  RESEARCH  limited  not  I n order  captures  processes  be  PROGRAMMING  system  application.  FUTURE  h a s been  decision  proposed  FOR  project  technologies  should  of thedetailed  a construction information  cycle  decision i sa l s o  and a v a i l a b l e  be c a t e g o r i z e d  i n formats  process required.  construction suitable f o r  computer a p p l i c a t i o n .  7.2.2  GRAPHICS  In  certain  construction  INTERFACE  types  a n d mass  of  assembly  geometry  and a standardized  types  interface For  can  of projects,  f o r problem  example,  be  CYCLE  project,  housing  typical  these  FOR  by  i n a high-rise  as  high-rise  projects,  relatively  the  simple  of b u i l d i n g components. F o r  i ti spossible  definition  such  development  defined set  DESIGN  t o design  and s o l u t i o n  construction  a  graphics  formulation.  project,  the plan  149 of  a  typical  building  floor  can be  components,  such  s e l e c t e d from a l i s t of  each  directly also  as  and  on the f l o o r  plan.  for site  graphically  columns  and l o c a t e d  subassembly  be used  defined  and the  and beams,  can be  i n the p l a n . The dimensions  components  can then  The f l o o r  planning  plan  be  entered  thus d e f i n e d can  and f o r studying  flyform  layouts.  7.2.3  INTEGRATION  The  process  production process. with  i s part  The a c t i v i t y project  information, collected  such  and  functions.  use  problem  the  activity  design  the  total  project  One management breakdown management  must  functions  in project  cost  be  integrated  so that  accounting support  Russell  function  at the  management  relevant  expenditures  of the d e c i s i o n  definition.  of  project  function  construction  cycle  can  other  system  with  required  [114] has i l l u s t r a t e d  relates  management  to other  system  be  and  f u n c t i o n can reduce the t o t a l e f f o r t  for  construction  of the t o t a l  management as  FUNCTIONS  a construction  design  Integration  the e s t i m a t i n g  OTHER MANAGEMENT  of d e s i g n i n g  level  other  described  WITH  how  functions i n  for  repetitive  projects. the requirements functions  structures hierarchy.  is  for integration  the  for The  of  standardization  a l l levels work  by Ponce-Campos and R i c c i  of  breakdown  project of  the  work  project  structures  [103] can be used as a  150 framework  by  which  the required  standardization  c a n be  achieved.  7.2.4  INTEGRATION  Taken solve  individually,  the construction  possible  existing  models  cannot  be used t o  However,  t o make u s e o f t h e m  i n thedecision  support  and  animation  design  as  sub-problems  however,  requires  prohibits  linear  mathematical  effort  reguired  "program  generators" which  and  generate  mathematical  analysis  could  of  mathematical  programming  could  design  i n  be  be d e v e l o p e d .  used  to  techniques, effort  the  greatly  required  be  problem.  programming  can interpret  t h e programs  simulation  dynamic and  use  will  i s  system  t h e impacts  programming  day-to-day  i t  i n a more  programming,  excessive  i t from  programming  user  of thea c t i v i t y  and  F o r example,  t o communicate  and d e t e r m i n i s t i c  such  Simulation  used  t o t h e system  manner  techniques,  alternatives.  c a n be  decisions  effective  then  MODELING T E C H N I Q U E S  design problem.  analyzing  certain  OTHER  cycle  for  solve  WITH  field.  that The  reduced i f  t h e network  logic  f o r s i m u l a t i o n and  151  7.2.5  DETAILED  PLANNING  OF CONSTRUCTION  CYCLE  OPERATIONS One thesis in  topic that  i s the assignment  other  words,  construction For  operation  that  another  technology individual At  Economy level  work  crew  by  Forms of  tasks  selected  tasks  photography,  crane  thirty  decided  t o t h e formwork after  the  o f one and a that  certain  half  s e tof  use of the crane f o r  process  associated  ina  t o use of t h e crane and  requires  design  crews,  t o the user.  minutes  period  (see figures  few p r o d u c t i o n  involves  with  assigning  the construction  6.6(a)  and  operations,  s p e c i a l i z e d hardware Corporation, To  production  industrial  within defined  of the operations  tower  prior  i n this  6.6(b))  to  members.  detail.  information, the  s e t o f work  i ndetail  i s assigned  and f o r a  has mentally  present,  documented  a  say  The o p e r a t i o n  s e t of  tasks  process  h a s t o be p e r f o r m e d  minutes.  the  operation  t h e user  tasks  90  This  has s t a r t e d  work  o f work  i n assigning  installation  discussed  the d e t a i l e d design  cycle.  example,  hours,  h a s n o t been  and  method  study  be u s e d .  suppliers,  been  collect  engineering  could  have  except  documented  document techniques  literature,  such  such  those as t h e  to  the  this  reguired  described i n as  time-lapse  152  BIBLIOGRAPHY  [1]  A g r a w a l , P.K., "Related A c t i v i t y Concept i n Assembly Line B a l a n c i n g " , I n t e r n a t i o n a l J o u r n a l of Production Research, v 23 n 2, Mar/Apr 1 9 8 5 , pp 403-421.  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