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Plastic behaviour and buckling of rolled structural steel members under compression and bending Irvine, Edward Charles Fordyce 1963

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PLASTIC OF  BEHAVIOUR  AND  ROLLED STRUCTURAL UNDER  COMPRESSION  BUCKLING  STEEL AND  MEMBERS  BENDING  by  EDWARD B.Sc  A  THESIS THE  CHARLES FORDYCE  (Eng.)  IRVINE  U n i v e r s i t y o f Aberdeen, 1956  S U B M I T T E D IN P A R T I A L REQUIREMENTS  FULFILMENT  OF THE D E G R E E  OF  M a s t e r o f Applied Science  in the D e p a r t m e n t of Civil Engineering We accept this thesis as conforming required standard  THE  UNIVERSITY  OF  BRITISH  September, 1963  to the  COLUMBIA  OF  *  In the  this thesis  r e q u i r e m e n t s f o r an  British  mission  for reference  for extensive  p u r p o s e s may  be  without  of my  Department  written  of  by  Library  the  fulfilment  of  University  of  s h a l l make i t f r e e l y  this thesis  agree for  that  i s understood  that  EnciNi's.^y.AHq Columbia,...  or  c o p y i n g , or  shall  per-  scholarly  Head o f my. Department  permission.  Cvv>\-  the  I further  for f i n a n c i a l gain  The U n i v e r s i t y of B r i t i s h V a n c o u v e r 8, Canada. Date  d e g r e e at  the  copying of  It  this thesis  that  in partial  arid s t u d y .  granted  representatives.  cation  advanced  Columbia, I agree  available  his  presenting  not  be  by publi-  allowed  ii ABSTRACT  T h i s r e s e a r c h into t h e properties W.F.,  of a 5 " x 5 " x l 6 l b  A 3 6 S t e e l , rolled s t r u c t u r a l member was undertaken  to determine the following: i - Yield s t r e s s distribution over t h e c r o s s section of the member as determined by coupon t e s t s . ii - Development of s t r a i n over the c r o s s section of the member, as measured by electric s t r a i n gauges, when subjected t o a) Axial loading, b) Bending Moment. iii - T h e e f f e c t of previous loading of a member as a column into the region o f yielding on i t s subsequent behaviour as a beam loaded t o f a i l u r e . The  following  results were obtained:  i - Yield s t r e s s , particularly the upper yield s t r e s s was not uniform over the c r o s s section. ii - T h e s t r a i n distribution in the plastic range was not uniform and varied f r o m c r o s s section t o c r o s s section and even a t closely adjacent points on the same c r o s s section. iii - Failure o f t h e member, due t o inadequate l a t e r a l support when loaded as a column, o c c u r r e d before complete yielding was achieved. T h e e f f e c t of this previous loading on the subsequent behaviour of t h e member as a beam loaded t o failure was inconclusive.  TABLE  OF  CONTENTS  CHAPTER I.  II.  III.  PAGE  M A T E R I A L AND  EQUIPMENT  1  Material  1  T e s t i n g Machines  2  E l e c t r i c S t r a i n Gauges and C e m e n t s . . . .  3  S t r a i n Indicating Equipment  3  YIELD  STRESS  . . . . . . . .  DISTRIBUTION  5  General D e s c r i p t i o n  5  Conclusion  7  COMPRESSION  TESTS  9  General D e s c r i p t i o n  IV.  9  T h e o r e t i c a l Considerations  12  Compression, T e s t Number 1  15  Compression T e s t Number 2  23  Compression T e s t Number 3  41  Conclusions  62  BENDING  TESTS  .  General D e s c r i p t i o n  63  Bending T e s t Number 1 Bending T e s t Number 2 Conclusions  63  . .  65 92 117  iv CHAPTER  PAGE  BIBLIOGRAPHY  118  REFERENCES  120  FIGURES  122  .  LIST  OF  TABLES  TABLE  PAGE  I  Compression T e s t  Number 1  19  II  Compression T e s t  Number 2  29  Cross Section A Cross Section B  III  IV  V  2-31  . •  33  Cross Section C  37  Cross Section D  39  Compression T e s t  Number 3  46  Cross Section A  50  Cross Section B ,  53  Cross Section C  56  Cross Section D  59  Bending T e s t  Number 1  69  Section B  74  S e c t i o n (j?  79  Section C  84  Bending T e s t Section B S e c t i o n (£ Section C  Number 2  92 99 105 I l l  CHAPTER M A T E R I A L S AND  I EQUIPMENT  Materials A l l t e s t s c a r r i e d out in this investigation were made on specimens cut f r o m a single as' rolled length of 5"x5"xl6lb W.F.  beam, of type A36  s t e e l , manufactured by t h e United  S t a t e s S t e e l Company and supplied by the Dominion Bridge Company. Specimens' A l , A 2  and A3  long.  Specimens A 4 and A 6  long.  Specimen A 5  was  were approximately 18"  . . • ' •1 we're" approximately ll -10Qj " ,  12' 00" long —  this member  '  was  supplied with both ends f a c e d normal to the axis. Coupons f o r the tension t e s t , described'' in C h a p t e r I I , were cut f r o m specimen A 2 .  T h e s e coupons were  approximately 1!' wide a t the ends and were machined down il  to approximately 0.50" in width over the middle 4""^. 0. t o t a l length of the coupons was change was  18" approximately.  The  No  made t o the thickness of the coupons which was  t h a t of the flange or  web.  T h e locations o f the t e s t specimens and of the coupons f o r the tension t e s t a r e shown in Figure l a and l b . 1  T e s t i n g Machines In the t e s t s undertaken in this investigation the f o l lowing t e s t i n g machines were used: i - 60 kip capacity Baldwin hydraulic universal t e s t i n g machine, ii - i+00 kip capacity Baldwin hydraulic universal t e s t i n g machine, iii - 2 0 0 kip capacity Tinus Olsen universal t e s t i n g machine.  electro-mechanical  In the hydraulically operated Baldwin machines i t was found t o be d i f f i c u l t t o maintain uniform slow r a t e s o f s t r a i n or t o maintain fixed s t r a i n s . In the Tinus Olsen machine an almost constant  strain  could be maintained by stopping the machine. T h e s t r a i n would, even in this case, vary slightly as the e f f e c t o f creep in the specimen would r e s u l t in a slight reduction in load.  T h i s reduction in load would cause a movement of t h e  lower loading p l a t f o r m  which actuates  the load pointer.  It  would also r e s u l t in a change o f s t r a i n in the s t r e s s e d members o f the t e s t i n g machine. opposite  T h e s e two e f f e c t s a r e in the  direction and the resultant i s , f o r the present  application, considered negligible. The intended  loading bed of this machine is equipped with wings  t o support the ends o f long beams in bending t e s t s .  3 T h e v e r t i c a l clearance is in excess of 12' 0". E l e c t r i c S t r a i n Gauges and C e m e n t s Preliminary t e s t s were carried out t o determine the suitability, within the plastic range, of the following types of s t r a i n gauges and cements. S t r a i n Gauges Philips T y p e P R  Cements 9814  Budd T y p e CC&-141-B  •  Budd T y p e HE-141-B  Eastman  910  Budd B3  Resin  Philips  9244/00 K i t  T h e most suitable gauge f o r the present application was found t o be the Philips P R  9814.  T h i s is a more  robust  gauge than the Budd gauges and has the f u r t h e r advantage in t h a t the leads may be soldered directly t o the terminals on the gauge without the use of a seperate  terminal block  as is advisable f o r the Budd Gauges. Of  the cements t e s t e d , the E a s t m a n 910 cement  found t o be, in the present others.  was  application, superior t o the  I t is rapid and simple t o use and requires no pro-  longed clamping and curing as did the other cements. S t r a i n Indicating Equipment T h e electric s t r a i n gauges were connected t o a Budd S t r a i n Indicator Model HW-1  through one or more o f the  4 following switching and balancing units, depending on the number o f gauges in use. i - Budd 10 channel switching and balancing unit, ii - Baldwin 6 channel switching and balancing unit Model S R 4, iii - Baldwin L i m a Hamilton 20 channel switching and balancing unit, iv  - Polyphase Instrument C o . 12 channel switching unit only. Model 1 2 S - 1  A l l the above equipment was found t o function s a t i s factorily. T h e Budd  S t r a i n Indicator was  rapid and easy to  operate and an improvement on the Baldwin S R indicator used in some of the preliminary t e s t s .  4 Type  L  CHAPTER  YIELD  General  STRESS  II  DISTRIBUTION  Description The  magnitude o f the yield s t r e s s f o r eleven locations  on t h e c r o s s section of the member, obtained by t e s t i n g in tension coupons c u t f r o m length A 2 , is shown in F i g u r e l b . The  value o f the ultimate s t r e s s , where this was obtained,  is also shown. The  f i r s t five t e s t s were conducted using  standard  wedge shaped grips t o hold t h e ends o f t h e coupons in the t e s t i n g machine.  T h e s e grips do not eliminate t h e possibility  of the specimen being subjected t o a bending moment as well as tension.  This, together  with t h e speed a t which the  t e s t s were conducted, prevented yield point.  t h e detection of the. upper  In these t e s t s t h e r e f o r e only t h e lower yield  s t r e s s and ultimate s t r e s s were found. The  remaining  six t e s t s were conducted using Templin  G r i p s t o hold t h e ends of t h e specimen.  T h e ends o f these  grips a r e held in the machine by lubricated spherical sockets which ensure t h a t t h e t e s t specimen is subjected t o tension only.  T h e s e last- t e s t s were also conducted a t a somewhat  6 slower r a t e o f s t r a i n and i t was thus possible t o d e t e c t  both  upper and lower yield s t r e s s e s . All  t h e above t e s t s were carried out using the 60 kip  capacity Baldwin machine and, as a r e s u l t , in the final six t e s t s t h e mean r a t e of s t r a i n varied f r o m a maximum  of 1 5  micro inches per inch per minute t o a minimum of a p p r o x — imately 2 micro inches per inch per minute. • The  influence o f s t r a i n r a t e on t h e lower yield s t r e s s  level has been investigated by Beedle and T a l l .  T h i s variation  of lower yield s t r e s s with r a t e o f s t r a i n is due t o t h e e f f e c t of c r e e p . Figure 2, and  T h e r e s u l t o f this investigation is shown in which has been reproduced in p a r t f r o m  Beedle  Tali's paper. In view o f t h e above it is assumed t h a t f o r t h e v e r y  low  r a t e s o f s t r a i n used in the coupon t e s t s the variation in  r a t e would not r e s u l t in a g r e a t e r  s c a t t e r o f r e s u l t s than  would be obtained had all t h e t e s t s been conducted a t a uniform r a t e o f s t r a i n . With regard  t o t h e upper yield s t r e s s , it is assumed  t h a t the above variations in s t r a i n r a t e would not have a significant e f f e c t on t h e r e s u l t s obtained.  T h i s is confirmed  t o some extent by the r e s u l t obtained f o r flange t i p coupon no.  7 Figure  lb.  T h i s coupon, which exhibited an unusually  7 high upper yield s t r e s s , was t e s t e d at a r a t e of s t r a i n approximately mid way between the limits s t a t e d above.  The  d i f f e r e n c e between t h e upper and lower yield s t r e s s amounted t o almost 25 per cent of t h e lower, yield s t r e s s and the resultant fall in load observed during t h e t e s t was very abrupt. For  the remaining coupons in which both yield s t r e s s e s  were d e t e c t e d ,  t h e d i f f e r e n c e amounted t o between 6 . 7  per cent and 2 . 7 per cent o f t h e lower yield s t r e s s . I t will be evident f r o m  Figure  l b t h a t in general,  the yield s t r e s s in the web is markedly g r e a t e r than t h a t in the flanges.  T h i s is in agreement with, the findings o f  Beedle and T a l l .  2  No a t t e m p t was made t o determine i f t h e yield s t r e s s at the junction o f t h e flange and web was g r e a t e r than t h a t at t h e flange tips as indicated in the commentary^ nor was any  a t t e m p t made t o determine t h e residual s t r e s s e s by  attaching s t r a i n gauges t o t h e coupons and obtaining before  readings  and a f t e r the coupon was cut f r o m t h e rolled section.  Conclusions i - T h e yield s t r e s s determined by coupon t e s t s is not uniform over t h e c r o s s section, particularly  8  t h a t of the upper yield s t r e s s , ii - The web  yield s t r e s s i s , in general, g r e a t e r in the than in the flange.  CHAPTER  III  COMPRESSION  TESTS  General D e s c r i p t i o n T h r e e seperate compression t e s t s were c a r r i e d out t o study the s t r e s s - s t r a i n c h a r a c t e r i s t i c s and  the  develop-  ment of yielding over the c r o s s section of the member when subjected  to axial loading.  Tests  numbers 1 and  of approximately 18"  and  2 were made on short  sections  2 4 " in length respectively and t e s t  number 3 on a 12'-0" long laterally supported member.  Tests  i  numbers 1 and 3 were made on the Tinus Olsen machine t e s t number 2 was  and  made on the 400 kip capacity Baldwin  machine. A pad,  universal head in conjunction  F i g u r e 4, was  used in all the above t e s t s to ensure  the load application to the upper end dural pad  also served  damage.  The  centered  and  was  not e c c e n t r i c .  The  t o p r o t e c t the loading head against  lower end  of the  members were carefully  r e s t e d on a dural plate placed as p r o t e c t i o n  the lower loading The  with a dural centering  on  platform.  ends of the members had  normal to their axis.  previously been milled  10 A l l the above t e s t s , with the exception as s t a t e d below, were c a r r i e d out using Philips Type P R  9814 s t r a i n  gauges attached t o the member by means of E a s t m a n 910 cement.  In t e s t number 2 however, two of the 44 gauges  used were Budd Metalfilm T y p e H E - 1 4 1 - B attached t o the member by means of Budd B 3  resin.  T h e s e two high elongation Budd gauges were used t o determine i f t h e r e was any marked d i f f e r e n c e in the p e r f o r mance o f the Budd and Philips gauges. was  No  such d i f f e r e n c e  detected. T h e value o f "e mean" given in the tabulation of  r e s u l t s was  obtained by dividing the t o t a l s t r a i n recorded  dial gauge by the original length of the member. t h r e e t e s t s the dial gauges recorded  by  In all  the movement of the  upper loading head housing relative t o the lower loading platf o r m and were t h e r e f o r e not directly influenced by any t i l t ing of the universal head. T h e values of "e. mean" plotted against load and s t r e s s f o r the t h r e e t e s t s are shown in Figure 5.  The  irregularity in the initial stage of the t e s t is caused by crushing the imperfectly milled ends, and the taking up of possible clearances under the end pads.  11 The  "e mean" value f o r zero s t r e s s may  be  obtained  by extrapolating the graphs downward to i n t e r s e c t the zero s t r a i n axis.  T h u s , the "e mean" values f o r zero s t r a i n are  approximately  150,  600,  and 230.  10  t e s t s numbers 1, 2 and 3 respectively.  in/in., f o r compression The  values of "e  mean" shown on the strain diagrams f o r the t h r e e compression t e s t s have been adjusted t o these new Figures 7 ,  9,  10 and  zero values,  12.  A.n approximate value f o r the maximum residual compressive s t r e s s may  be obtained f r o m F i g u r e 5 by  ing the s t r e s s at which the s t r e s s - s t r a i n curve becomes non-linear.  determin-  first  T h i s appears to take place at a s t r e s s  somewhat lower than 34 k . s . i . indicating a residual compressive s t r e s s of about 6 k . s . i . value suggested  by Figure 3.  T h i s is approximately  half the  T h i s figure has been copied  directly f r o m the Commentary^ and r e p r e s e n t s the assumed cooling residual s t r e s s p a t t e r n f o r wide flanged s e c t i o n s . The  actual residual s t r e s s e s may,  however, d i f f e r consider-  ably f r o m those represented above as has been demonstrated by Beedle  and  The expected  Tall.5  actual s t r a i n value at which yielding may  be  to commence in the flange tips of an as rolled sec-  tion in compression would, in view of the residual s t r e s s e s ,  12 be considerably lower than t h e actual s t r a i n a t which yielding would be expected t o occur  in the web.  T h e r e v e r s e of* t h e  above would occur f o r a member in tension. Since t h e value of t h e assumed cooling residual compression s t r e s s is g r e a t e r than t h e assumed cooling residual tension s t r e s s , yielding in a member will t h e r e f o r e occur a t a lower load in a member loaded in compression than in the same member loaded  in tension.  I t will be evident t h e r e f o r e t h a t t h e elastic properties of an as rolled section cannot be determined by coupon t e s t s alone and moreover t h e elastic limits of a section will not in general be t h e same in tension and compression. Theoretical The  Considerations compression t e s t s investigated in this thesis  were c a r r i e d out using a universal head f o r the application o f the load t o t h e upper end o f the member. In this type o f head, Figure 6, the center o f c u r vature  of the spherical s u r f a c e should, ideally, coincide  with t h e center o f the loading f a c e .  with  T h e t o p o f the member  is t h e r e f o r e in e f f e c t pin jointed. The  lower end of t h e member • r e s t e d on a dural pad  placed directly on t h e bed plate of t h e machine.  13 The  e f f e c t of yielding a t one edge of the member,  loaded as indicated above, is now investigated.  I n this  invesitgation the e f f e c t o f f r i c t i o n in t h e universal head and the presence of the dural bearing pads has been neglected. Consider yielding t o take place a t one edge of a member.  T h i s yielding will cause t h e f o r m a t i o n of a wedge  shaped element which, in t u r n , will result in the angular deformation o f the member a t this section, F i g u r e 6. A.t  the upper end o f t h e member the universal head  will r o t a t e t o accommodate this angular deformation. At  the lower end no such rotation can take place and  the r e s u l t a n t o f the load will move out t o w a r d s t h e opposite edge o f the member t o t h a t a t which t h e initial yielding commenced.  T h i s eccentric loading will f i r s t  cause a very  small angular elastic deformation of t h e lower p a r t of t h e member and once t h e limit o f this small angular deformation has been reached t h e eccentric loading will cause a second focus o f yielding t o develop a t the lower edge opposite t o t h a t a t which t h e initial yielding commenced. Let  (p  e  be t h e limit o f this angular elastic d e f o r -  mation o f the lower p a r t of the member.  I t will be seen  by comparing F i g u r e 6, a, b, and c t h a t t h e extent of  14  yielding a t the initial location t h a t can take place b e f o r e yielding develops a t the bottom opposite f a c e will be smaller as the location o f t h e initial yielding section approaches t h e lower end.  In other words, if initial yielding commences near  the t o p edge o f t h e member, then t h e extent o f this yielding, before a new focus of yielding develops a t t h e opposite lower edge, is likely t o be g r e a t e r than t h a t had t h e initial yielding section been near t h e lower edge. It  is also evident t h a t if no r o t a t i o n of t h e univer-  sal head takes place then if yielding commences a t any edge of the member this yielding will be immediately suppressed o r , alternatively, yielding must also develop a t some place at  the opposite  edge.  In t h e 12'-00" laterally supported  member t h e above  p a t t e r n will be • considerably modified by t h e l a t e r a l  supports.  No lateral deflection will be possible about the s t r o n g axis as the member is continuously r e s t r a i n e d in this direction. L a t e r a l deflection i s , however, possible about t h e weak axis between t h e clamps. at  T h i s is in f a c t what took place  t h e lower end o f t h e member. Thurlimann has made t h e following s t a t e m e n t in his  investigation of the buckling o f compression members beyond yielding.  15 Inspection of a typical s t r e s s s t r a i n curve, suggests t h a t steel specimens deform homogenously under yield s t r e s s . However, observations of the actual behaviour shows t h a t yielding occurs in extremely thin layers forming successively along the length of the specimen. T h e s e slip bands are oriented along the planes of maximum shear s t r e s s . The local s t r a i n across a band increases instantaneously f r o m e to e ^.. Yielding commences at a weak spot (inclusions, s t r e s s concentrations, etc.) and spread f r o m this point over the entire length of the specimen. I t can t h e r e f o r e be concluded t h a t during yielding p a r t of the material is still elastic whereas other regions have reached the strain-hardening range. Only a f t e r complete yielding has taken place throughout the entire length of the specimen do the material properties become homogeneous again. The  symbols used in the above quotation are defined  as follows: e ^  = s t r a i n corresponding plastic yielding.  e.£. = s t r a i n at onset s  The  to theoretical onset  of s t r a i n  above s t a t e m e n t has  of  hardening.  in no instance been con-  firmed by s t r a i n gauge readings in this t h e s i s .  Compression T e s t  Number 1 i  T h i s compression t e s t using the Tinus Olsen was  machine  c a r r i e d out on the 18" long member A l , F i g u r e l a and  Figure  4. E i g h t Philips s t r a i n gauges were attached to the  ?  16 to the member a t mid height as shown in Figure 4. S e t s of readings numbers 1 t o 9 were taken the machine stopped.  with  T h e remaining s e t s of readings were  obtained with the machine operating a t a very low r a t e of strain.  In view o f the low r a t e o f s t r a i n and t h e f a c t  t h a t a s e t of 8 readings could be taken in under 30 seconds no adjustment  has been made t o the readings.  The results  of this t e s t are given in Table I and a r e shown graphically in F i g u r e 7 • During t h e recording o f the final s e t of s t a t i c readings, s e t number 9, a fall in load was observed,  indi-  cating t h a t creep and t h e r e f o r e yielding was taking place. The  s t r a i n gauge readings however indicate t h a t yielding had  commenced a t about s e t number 6 and a t least as early as set  number 7, and t h e s t r e s s - s t r a i n curve F i g u r e 5 indi-  i cates t h a t yielding had commenced number 4.  a t least as early as s e t  A s no drop in load was observed  during t h e  period t h e machine was stopped t o r e c o r d s e t s number 7 and 8 this yielding must have been quite localized.  T h i s is  confirmed by the v e r y gradual change in slope o f the s t r e s s s t r a i n curve, F i g u r e 5. S h o r t l y b e f o r e readings o f s e t number 16 were taken  17 a cracking noise was  heard in the drive mechanism o f the  t e s t i n g machine and the machine was The of  creep.  immediately stopped.  subsequent s e t s of readings indicate the e f f e c t In a t h r e e day period this amounted t o a fall in  s t r e s s of about 1.7 k . s . i . representing about 1+ per cent of the  s t r e s s a t which the machine was  stopped.  Almost  per  cent of this drop in s t r e s s took place in the f i r s t  75 17.5  minutes. T h r e e days a f t e r stopping the machine it was decided to  unload the specimen.  I t was  then found t h a t a break  down had occurred in the drive mechanism.  T h i s resulted in  a six weeks delay in the t e s t i n g programme. It the  is evident f r o m an examination of F i g u r e 7 t h a t  unevenness  elastic range.  in the s t r e s s p a t t e r n is present in the T h i s is thought to be due t o slight irregular-  ities in the milling of the ends of the member normal to the axis and also possibly, unevenness It  of the. end pads.  will be seen f r o m the s t r a i n gauge readings t h a t  yielding commenced f i r s t at gauge 3 a t about s e t number 6 and certainly by s e t number 7.  The  s t r e s s - s t r a i n curve,  F i g u r e 5, indicates t h a t yielding commenced at least as early as s e t number 4. . T h i s yielding must t h e r e f o r e have taken  18 place a t a location where t h e r e were no s t r a i n gauges. The occurred  f i r s t yielding recorded  at the flange t i p s .  by t h e s t r a i n gauges  T h i s is in agreement with t h e  assumed residual s t r e s s p a t t e r n Figure 3 . As  s t r a i n is increased i t will be seen t h a t t h e develop-  ment o f yielding is g r e a t e s t a t the flange tips and least a t the center of t h e web.-  T h e mean values o f e^ and e^ a r e  consistently g r e a t e r than eg and similarly the mean values o f e^ and e^ are g r e a t e r than e^ i . e . ,  |  (e  ?  + e  l }  |  (e  3  + e  5  >  e  g  )>e  4  A l s o as yielding develops i t will be seen t h a t (e^ + e ) 8  y  (e + 2  e ) 6  I t is not possible f o r t h e above s t r a i n p a t t e r n s t o exist throughout t h e length o f t h e member thus,  elsewhere  in the member, an opposite o r compensatory p a t t e r n s  must  occur. T h i s irregular  s t r a i n p a t t e r n is c o n t r a r y t o t h e  s t a t e m e n t o f Thurlimann discussed earlier in this  Chapter.  TABLE COMPRESSION  Set no.  Load kips  Time  9 Feb.  o— mean k.s.i.  I  TEST  Dial Gauge  NUMBER  1  e mean Micro in/in  Temp. 0  Remarks  JT>  63.  0  09.15  0  1  09.52  40  2  10.10  80 -  :3  10.29  4  0  8.51  0"  0  0.0093  517  16.02  0.0151  839  120  24.53  0.0209  1160  10.55  160  34.04  0.0277  1540  5  10.58  170  36.17  0.0294  1635  6  11.06  175  37.23  0.0311  1730  7  11.10  180  38.30  0.0325  1810  8  11.14  185  39.36  0.0353  I960  9  11.16  187  39.79  0.0367  2040  70°  Specimen A l -  Drop of 0 . 5 0 kip ~ 0 . 1 k . s . i .  TABLE Set no.  Time  I  (continued)  Load kips  u—mean k.s.i.  Dial Gauge  e mean Temp. Micro in/in °F  10  11.20  190  40.43  0.0403  2240  11  11.31  192.8  41.03  0.0558  3100  12  11.42  192.6  40.99  0.0746  4130  13  11.51  192.6  40.99  0.0913  5070  14 .  12.00  196.1  41.96  0.1088  6040  15  12.09  193.3  41.13  0.1238  6875  16  12.175  195.8  41.66  0.1373  7620  17  .12.35  190.0  40.43  0.1375  7650  18  17.45  188.35  40.12  0.1381  7670  19  .10 F e b . 11.00  188.0  40.05  0.1381  7670  20  11 F e b . 09.35  187.85  39.97  0.1383  7700  21  12 F e b . 13.20  187.75  39.95  0.1382  7680  ' Remarks  70°  machine stopped break down  ro o  TABLE  Set no  2  1  I  (continued)  S t r a i n Gauge Reading 4 5  3  6  8  7  '0  0  0  0  330  292  258  2  202  638  628  586  530  170 "  450  801  827  927  ' 866  812'  385  715  1,180  1072  1,170  1202  1120  1110  600  1035  5  1,235  1130  1,221  1250  1025  1177  658  1115 .  6  1,270  1190  1,525  1280  1102  1227  710  1182  7  1,307  1242  2,810  1335  1055  1270  760  1250  8  .1,320  1335  6,810  1318  1050  1390  875  1295  1,325  1405  10,010  1290  1032  1425  925  1330  10  1,345  1520  11,910  1282  1080  1568  1010  1370  11  1,660  1700  13,820  1270  1260  1710  1430  1615  0  0  0  0  1  430  265  352  2  732  532  3  975  4  9  .  0.  ro  TABLE  Set no  I  (continued)  S t r a i n Gauge Reading 1  2  3  4  6  5  7  8  12  6,470  1760  15,595  1240  1525  1815  3385  1710  13  9,580  2125  16,970  2300  1710  2227  5485  2715  14  10,820  2680  17,610  5350  2900  2748  7020  4040  15  11,190  3225  18,170  6345  4960  3260  768O  5420  16  11,555  3790  18,510  6820  7950  3960  8000  6290  17  11,555  3845  18,510  6840  8130  4000  7890  6310  3860  18,435  6828  8140  3975  7500  6265  .  18 1-0 F e b . 19  11,514  20  11,500  3850  18,418  6793  8080  3960  7500  6250  21  12 F e b . 11,490  3850  18,410  6790  8073  3957  7470  6248  11 F e b .  23 Compression  Test  Number 2  T h i s compression t e s t using the 4 0 0 kip Baldwin machine was  made on a 2 4 " long specimen cut f r o m the end  of member A 4 in C h a p t e r I V .  a f t e r completion of the bending t e s t s described As  the ends of the member A 4  were sub-  jected t o bending moments well within the elastic range the cooling residual s t r e s s e s are assumed t o have remained unaltered  by these bending t e s t s .  In the compression t e s t described  in this section t h r e e  s e t s of eight s t r a i n gauges were attached sections A , B  C  and D  t o the member a t  and 20 gauges were attached  as shown in Figure 8.  a t section  A l l the above were Philips P R  gauges except gauges 8 and 10 at section B ,  which, f o r  comparison purposes, were Budd HE-141-B metalfilm elongation gauges.  No  9814  high  noticeable d i f f e r e n c e in the p e r f o r -  mance pf the Budd and Philips gauges was  observed.  In order t o r e s t r a i n the 'flanges o f the member f r o m buckling inwards, carriage bolts were placed between the flanges a t intervals of not more than 6 " and the nuts backed o f f hand tight against the opposite  flange.  To  prevent o u t -  ward buckling of the flanges these were r e s t r a i n e d by 1 l/2"x 1 l/2"x 1 / 4 "  angles and to minimize the possible local  e f f e c t of these angles on the compression s t r a i n p a t t e r n a  24 wire was placed under each angle as shown in F i g u r e 8. No local buckling of the flanges was observed the member had entered the s t r a i n hardening A  until  range.  slight bending o f t h e member about the s t r o n g axis  with gauges 3, 4, 5 sections A , C and D on t h e concave side appeared 14.  t o take place a t approximately t h e time of s e t no.  No evidence o f this is manifest in t h e s t r a i n gauge  readings and the apparent The  bending subsequently  disappeared.  f i r s t t h r e e s e t s o f readings in this t e s t  made a t constant load.  The. remainder  o f the t e s t  were was made  with the machine running and a continuous series o f readings were taken.  T h e sequence o f the readings was f r o m  1, section A t o gauge 8, section D.  gauge  E a c h s e t o f 44 read-  ings was subsequently adjusted, by direct proportion, t o the time o f reading in each s e t a t which t h e g r e a t e s t s t r a i n increment  was r e c o r d e d .  F o r example, in t h e sequence o f readings commencing at  i l : 0 1 a.m. and terminating a t 11:11 a.m. t h e g r e a t e s t  s t r a i n increment  over t h e s t r a i n readings in t h e previous  sequence o c c u r r e d a t gauge 7 section C and this s t r a i n gauge reading was 10,315 micro in. per i n . ; gauge C 7 is t h e 3 5 t h gauge in the sequence and t h e r e f o r e t h e time a t which this  i  i  !  25 reading was 11:01  taken i s , by direct proportion, + j£  a.m.  (11:11 - 11:01) = 11:09  reading at the beginning and and  191.0  190.2  + ^ 44  . The  load  end of this sequence was  kips respectively.  (11:09 a.m.)  a.m.  190.2  T h u s the load at the time  at which gauge C 7 was (191-.0 - 190.2) = 190.8  read is  —  kips or a s t r e s s of  40.6  k.s.i. 1  S t r a i n gauge C6  was  read -J-J^ of a sequence before  s t r a i n gauge C 7 , the reading was  1 0 . 4 0 5 micro in. per in.  and the increment to the reading in the following sequence was  1 4 2 5 micro in. per i n . , thus the reading at gauge  adjusted t o 1 1 : 0 9 a.m.  is 1 0 , 4 0 5 +  C6  = 1 0 , 4 3 7 micro in.  per in. 1  Similarly gauge C8 s t r a i n gauge G 7 ,  was  read ~^JT  the reading was  of a sequence a f t e r  1 0 , 4 6 5 micro in. per in.,  and the increment f r o m the previous sequence was micro in. per in.  T h u s the reading at gauge C8  2895  adjusted to  p on c  11:09  a.m.  is 1 0 , 4 6 5  - —p j^— =  10,400  micro in. per in.  A l l the other gauge readings in the sequence were" adjusted in a similar manner and the final result is shown as set 10 in Table I I .  The  other sequences were similarly  adjusted and are given in Table I I and are shown graphically in Figure 9 a to d and  Figure  10.  26 In F i g u r e 9 the s t r a i n gauge numbering f o r section B is t h a t shown in parenthesis in Table I I .  T h i s numbering  corresponds t o the eight gauge s e t s used a t sections A , C and D. An  examination of the t e s t r e s u l t s (shown in Figure  9) reveals an initial elastic s t r a i n p a t t e r n in the flanges somewhat higher initial s t r a i n s present than are present The  with  a t gauges 7 and 5  a t the opposite flange t i p s .  p a t t e r n appears t o have been caused by irregular-  ities in the dural end pads and/or the milling o f t h e ends o f the specimen normal t o t h e axis. The  subsequent adjustment t o this elastic s t r a i n p a t -  t e r n a t section A  would appear t o have been caused by a  r o t a t i o n o f the universal head. Yielding appears t o have f i r s t  s t a r t e d a t t h e location  of gauge 7 and i t would appear t h a t this yielding was  trig-  gered by the initial elastic s t r a i n p a t t e r n a s s i s t e d perhaps by the cooling residual compression s t r e s s .  I t is also possible,  however, t h a t the flange t i p a t gauge 1 may have been unusually s t r o n g or may have possessed  an unusually high upper  yield s t r e s s similar t o t h a t found in coupon 7, F i g u r e l b . It  will be seen t h a t as the general s t r a i n is increased  the s t r a i n a t gauges 7 increases more than the s t r a i n a t  27 gauges 1. ••A. similar p a t t e r n as t h a t described above is also evident in gauges 5 and 3.  T h i s p a t t e r n is however  present  at sections B and C only.  I t will also be seen t h a t in  general the s t r a i n a t gauges 4 and 8 a r e approximately mid way between the s t r a i n ^ s a t the corresponding  flange t i p s .  I t would appear f r o m the above t h a t bending of t h e members about the weak axis has occurred  a t sections B and C .  T h e o r e t i c a l considerations discussed in this  chapter  suggest t h a t a r e v e r s a l o f the s t r a i n p a t t e r n shown a t s e c tions B and C should occur  a t the lower end of t h e member.  T h i s is confirmed t o some extent by t h e s t r a i n p a t t e r n a t gauges 3 and 5, section D. T h e r e is also evidence o f bending about the strong axis occurring a t sections B and C .  T h e strains a t gauges  8 a r e g r e a t e r than those a t gauge 4 and the sum o f the strains a t gauges 4 and 8 is approximately equal t o the sum of the s t r a i n s a t gauges 6 and 2. p a t t e r n a t gauges 4 and 8 occurs  A  also a t section D .  T h e s t r a i n p a t t e r n recorded tion B is shown in Figure 10.  r e v e r s a l o f this s t r a i n  at the 20 gauges a t sec-  T h i s p a t t e r n is in general  agreement with the 8 gauge p a t t e r n discussed earlier.  It  28 will be seen however t h a t adjacent  pairs of gauges are in some instances  different. and  (in a s e t ) the s t r a i n reading at considerably-  F o r example, gauges 16 and 18 f o r s e t s no. 12  no. 1 5 J and f o r gauges 10 and 12 f o r s e t no. 8 i t is  possible t h a t this d i f f e r e n c e may  have been caused by local  buckling. A s s t r a i n hardening is approached t h e r e appears t o be a general levelling out of s t r a i n s a t all sections.  I  TABLE COMPRESSION  Set no.  Time  Load kips  0  0  o-mean k.s.i.  II  TEST  Dial Gauge  NUMBER  2  e mean Micro in/in  Temp. °F  Remarks  0  0  0  69°  Specimen cut f r o m end o f  70°  A4.  1  09.31  40  8.51  0.024  1,000  2  09.44  80  17.02  0.033  1,375  3  09.59  120  25.53  0.042  1,750  4  10.16  144.3  30.70  0.048  2,000  5  10.23  170.0  36.17  0.056  2,330  6  10.33  189.9  40.41  0.070  2,920  7  10.42  190.5  40.54  0.093  3,870  8  10.475  190.3  40.49  0.110  4,590  9  10.55  190.2  40.47  0.137  5,720  10  11.09  190.8  40.60  0.184  7,670  11  11.17  191.55  40.76  0.215  8,970  TABLE o-mean k.s.i.  II  (continued)  Set no  Time  Load kips  Dial Gauge  e mean Micro in/in  12  11.315  193.8  41.24  0.269  11,200  13  11.42  197.8  42.06  0.318  13,250  14  11.46  198.6  42.26  0.326 -  13,600  15  12.385  197.5  42.03  0.373  15,500  16  13.20  207.2  44.08  0.403  16,800  17  13.26  209.4  44.55  9.424  17,650  18  13.37  216.6  46.09  0.479  19,930  19  13,505  225.4  47.95  0.541  22,550  Temp. °F  Remarks  o  TABLE  II  (continued)  CROSS SECTION  A  S t r a i n Gauge Reading . 4 5  Set no  1  2  3  0  0  0  0  0  1  225  •" 240  195  2  515  • 506  3  813  4  1,003  5  1,265  1,209  1,182  6  1,505  1,743  7  1,650  8  6  7,  8  0  0  0  0  215  268  250  440  327  478 '  485  540  510  708  605  797  782  776  818  802  946  900  988 .  971  952  989  992  1,072  1,098  1,151  1,166  1,199  1,187  1,303  1,380  1,688  1,310  1,640  1,900  2,040  2,440  1,513  1,905  1,401  1,912  2,830  2,776  2,096  2,564  2,617  2,066  1,357  1,979  3,741  3,363  9  3,850  2,718  4,790  2,542  1,363  2,043  4,754  4,543  .0  7,340  3,081  7,423  5,520  1,387  2,239  6,835  7,505  ;  .  TABLE  Set no  II  (continued)  Strain Gauge Reading 6 5 4  7  8  2,795  8,920  8,724  4,685  6,955  12,275  9,570  13,355  9,830  11,680  12,880  10,810  19,307  13,460  11,800  12,344  13,488  10,994  11,474  19,672  14,723  15,905  14,530  13,700  12,990  12,955  11,815  19,805  15,315  16,020  15,535  14,005  14,148  17  13,602  12,110  19,903  15,760  16,926  16,226  14,250  14,496  18  15,030  12,480  20,384  17,263  18,458  18,106  15,292  16,780  19  17,485  7,330  21,520  19,295  20,362  19,423  16,780  19,210  1  2  3  11  8,542  4,142  8,445  8,735  1,425  12  10,010  8,180  14,055  12,545  13  11,028  11,760  18,840  14  11,302  12,020  15  11,948  16  ro  TABLE CROSS Set no  . 1 (1)  2  3  II  (continued)  SECTION  B  S t r a i n Gauge Reading 4 5 6 (2)  7 (3)  8  9 (4)  10  0  0  0  0  0  0  0  0  0  0  0  1  21i+  267  295  268  248  215  190  200  222  252  2  500  556  575  550  532  495  470  485  505  546  3  785  855  868  844  823  788  775  780  798  830  4  964  1,032  1,043  1,020  997  958  936  946  966  997  5  1,159  1,231  1,347  1,237  1,201  1,163  1,153  1,157  1,180  1,216  6  1,239  1,346  1,692  1,689  1,874  1,282  1,330  1,288  1,384  3,085  7  1,532  1,249  2,323  2,045  3,820  1,315  1,315  1,283  1,467  6,790  8  2,064  1,277  3,285  2,825  5,785  1,366  1,302  1,268 .  1,820  9,357  9  2,680  1,368  5,119  4,522  8,528  1,422  1,339  1,250  3,020 12,341  10  2,553  1,535  7,140  7,185  9,922  1,805  1,2-66  1,302  4,338 13,382  TABLE  Set no  1 (1)  2  3  II  (continued)  S t r a i n Gauge Reading 6 4 5 (2)  7 (3)  8  9 (4)  1'  11  2,505  1,587  9,610  8,137  10,416  2,035  1,220  1,335  4,815 13,727  12  2,442  3,536  10,840  9,710  11,079  2,681  1,171  1,493  5,969 14,416  13  2,593  4,965  12,257  10,979  11,775.  3,620  1,179  1,786  8,060 15,416  14  2,629  5,202  12,490  10,978  11,905  3,786  1,188  1,844  8,630 15,595  15  5,904  7,511  13,812  12,337  13,133  5,715  2,012  2,621  11,605 16,808  16  10,485  10,900  15,575  13,905  14,850  9,780  5,630  5,120  14,585 17,355  17  13,170  12,210  16,524  14,780  16,070  12,404  7,986  6,970  15,604 17,480  18  16,378  14,676  18,693  16,512  18,584  11,350  12,649  11,840  17,554 18,408  19  19,340  4,130  21,110  18,190  21,315  4,682  17,200  16,392  19,580 20,068  <u0  TABLE Set no  II  (continued)  S t r a i n Gauge Reading 16 15 17 14 (6) (7)  18  19 (8)  20  0  0  0  0  375  430  380  327  278  587  650  708  660  610  560  848  875  935  1,048  944  896  848  987  1,014  1,037  1,097  1,197  1,095.  1,046  998  1,184  1,201  1,246  1,266  1,257  1,355  1,248  1,262  1,195  1,690  1,435  2,158  1,819  1,763  1,250  1,940  1,260  2,610  1,340  7  3,745  3,427  4,902  3,260  2,533  1,269  2,484  1,214  6,365  1,307  8  6,055  4,400  7,407  4,654  3,235  1,333  3,195  1,204  9,520  1,310  9  9,989  9,800  10,837  6,685  5,175  1,569  7,163  1,170  10,824  1,253  .0  14,585  11,793  12,770  8,985  7,960  5,720  13,692  2,970  11,992  2,347  11 (5)  12  13  0  0  0  0  0  0  0  1  272  260  252  277  310  2  555  540  530  555  3  842  830  823  4  1,008  998  5  1,205  6  TABLE Set no  11 (5)  12  13  II  (continued)  S t r a i n Gauge Reading 16 17 15 14 (6) (7)  18  19 (8)  20  11  16,141  12,491  13,509  10,296  9,705  10,020  15,573  5,011  12,857  2,667  12  18,395  13,668 -14,385  11,905  11,950  14,673  17,767  9,168  13,897  3,239  13  20,550  15,100  15,237  13,202  13,667  16,907  19,820  11,782  14,594  3,905  14  20,933  15,440  15,348  13,510  14,000  17,225  20,220  12,225  14,748  4,055  15  22,313  15,711  16,296  15,195  15,520  18,390  21,772  14,025  15,428  5,010  16  22,480  15,660  18,410  17,180  17,460  19,106  22,140  15,080  15,280  7,910  17  22,412  15,812  19,400  18,010  18,370  19,470  22,007  15,495  16,400  9,460  18  22,287  16,490  21,690  19,924  20,565  19,925  21,984  16,567  18,320 12,808  19  22,682  17,238  24,590  22,330  23,502  19,580  22,336  18,252  21,379 15,982  TABLE  II  (continued)  CROSS SECTION  C  S t r a i n Gauge Reading 4 5  Set no  1  2  3  0  0  • 0  0  0  1  210  268  185  2  482  556  3  758  860  4  902  5  6  7  8  0  0  0  0  225  265  262  410  320  460  510  563  550  685  605  745 •  805  860  838  990  900  1,019  894  964  1,016  990  1,165  1,049  1,080  1,246  1,104  1,176  1,219  1,224  1,440  1,255  6  1,140  1,717  1,350  1,395  1,420  1,945  2,520  1,575  7  1,305  2,516  1,669  1,260  1,528  3,822  3,388  2,697  8  1,645  3,258  2,108  1,235  1,620  5,495  3,374  4,515  9  2,261  4,968  2,508  1,265  2,422  7,280  3,898  6,670  10  2,322  8,395  2,310  2,005  5,415  10,437  10,315  10,400  TABLE Set no  II  (continued)  S t r a i n Gauge Reading 6 5 4  7  8  1  2  3  11  2,194  9,244  2,186  2,943  10,275  11,506  13,251  10,730  12  1,878  10,303  2,054  4,155  15,405  13,046  15,945  12,195  13  1,776  10,962  2,188  5,125  16,740  18,000  17,072  13,140  14  1,777  11,073  2,300  5,430  17,020  14,905  17,115  13,320  15  1,869  11,390  2,980  6,915  18,200  14,145  16,130  14,166  16  3,400  11,980  6,800  9,185  18,579  14,940  12,455  15,640  17  5,590  12,060  9,450  10,490  18,553  15,590  13,335  16,395  18  10,590  12,962  14,800  13,552  18,663  17,204  13,300  18,314  19  15,850  11,630  19,045  16,340  19,615  19,072  13,580  20,378  CO  TABLE  II  (continued)  CROSS SECTION  D  S t r a i n Gauge Reading 6 5 4  Set no  1  2  3  0  0  0  0  0  0  1  217  260  298  232  2  490  ' 537  567  3  770  833  4  908  5  7  8  0  0  0  284  265  425  320  510  575  545  710  598  850.  • 808  905  845  995  885  989  994  960  1,069  1,006  1,158  1,032  1,096  1,200  1,196  1^185  1,261  1,197  1,416  ,1,225  6  1,155  1,625  2,040  1,401  1,321  1,500  4,590  1,453  7  1,191  2,215  5,324  1,669  1,332  1,600  8,565  1,540  8  1,215  2,240  7,730  2,145  1,330  1,617  11,395  1,546  9  1,102  3,660  9,436  2,910  1,337  1,649  14,070  2,870  10  1,011  5,600  9,995  6,555  1,445  1,990  16,203  2,400 U3  TABLE Set no  II  (continued)  S t r a i n Gauge Reading • 4 5  6  7  8  1,930  3,105  16,886  2,500  9,705  6,116  7,475  17,750  5,377  10,618  12,087  11,275  10,700  18,703  9,467  18,400  10,890  12,450  11,745  11,030  18,833  10,070  9,785  - 19,477  12,190  14,148  13,975  12,445  19,400  13,750  16  11,778  20,271  13,170  15,370  15,893  13,500  19,895  14,223  17  12,570  28,805  13,780  15,902  16,700  14,015  20,315  14,900  18  14,750  17,935  15,785  17,410  18,224  15,615  21,725  16,650  19  17,594  9,030  18,558  19,220  18,991  17,340  23,233  18,850  1  2  3  11  920  8,220  10,027  7,815  12  2,860  14,600  10,157  13  7,008  17,910  14  7,500  15  o  41 Compression T e s t  Number 3  T h i s t e s t , using t h e Tinus Olsen machine, was made on t h e 12'-0" member A53. F i g u r e l a . I t was hoped in this t e s t t o compress t h e member s u f f i c i e n t l y t o cause t h e entire member t o enter t h e plastic range and t h e r e b y remove t h e e f f e c t o f the residual s t r e s s e s and t h e upper yield point.  I t was then proposed t o compare  the performance o f this member in bending against t h a t o f a similar member which had not been pre-compressed.  The  t e s t had, however^., t o be stopped before complete yielding was achieved  owing t o t h e development o f local bending about  the weak axis a t t h e lower end. T h e r e s u l t s o f t h e subsequent bending t e s t s a r e described in C h a p t e r I V . In this column t e s t f o u r s e t s o f eight Philips s t r a i n gauges were a t t a c h e d t o t h e member a t t h e locations shown in F i g u r e 11. To  r e s t r a i n t h e member f r o m buckling i t was sup-  ported on either side by members Ai+ and A.6 as shown in t h e above f i g u r e .  T h e contact f a c e s o f t h e member were  greased, and where, due t o slight irregularities in t h e shape and s t r a i g h t n e s s o f t h e member gaps existed in t h e c o n t a c t f a c e s , b r a s s shims were inserted a t intervals o f not more  42 than six inches t o take up this gap.  To  prevent any local  inward buckling of the flanges, these were held a p a r t a t intervals of not more than six inches by l / 2 " x 3 carriage bolts the nuts of which had been backed  3/4" o f f hand  tight against the adjacent flange. The height was  clamp holding the members t o g e t h e r a t mid bolted up s u f f i c i e n t l y tight t o ensure t h a t  any  relative movement would take place f r o m the top and bottom t o w a r d s mid height.  The  remaining clamps were s u f f i c i e n t l y  loose t o allow this movement t o take place but a t the same time tight enough t o maintain the members in c o n t a c t . T h i s method of restraining  the member was  be- inadequate in t h a t i t failed t o provide complete  found t o restraint  against local bending about the weak axis and f o r this reason the t e s t had t o be halted b e f o r e complete achieved.  There  either the web The are  was  yielding  was  no visible evidence of local buckling of  or flanges.  results of this t e s t are given in Table 3 and  shown graphically in F i g u r e 12 a t o d.  A l l readings  shown in the above table were taken with the machine stopped.  I t will be seen t h a t , in general, two  readings were taken a t each strain, increment. set  was  s e t s of The  first  taken immediately following the increment and the  43 second set was creep had  taken some minutes l a t e r a f t e r the  taken place.  gauge 1 section A An  The  initial  sequence of reading was  to gauge 8 section  from  D.  examination of the t e s t r e s u l t s reveals an initial  elastic s t r a i n p a t t e r n in the flanges similar to t h a t observed in column t e s t number 2 with somewhat higher initial s t r a i n s present  at gauges 7 and  5 than are present  a t the  opposite  flange t i p s . The  p a t t e r n appears to have been caused by  arities in the dural end  pads and/or the milling o f the ends  of the specimen normal t o the axis and,  as would be  this p a t t e r n is most marked at section D, to the lower end  of the  ( 3 4 . 0 4 k.s.i.) and  expected,  which is n e a r e s t  member.  Yielding appears to have f i r s t o c c u r r e d ber k  irregul-  by set num-  is evident at gauge 1 section  C.  T h i s is confirmed by the f a c t t h a t the e f f e c t of creep f i r s t observed during the period the machine was r e c o r d set number 4 and  was  stopped to  by the f i r s t indication o f  non  linearity in the s t r e s s - s t r a i n curve F i g u r e 5 a t about 3 4 k.s.i.  T h i s f i r s t location o f / yielding at a flange t i p is in  agreement with the assumed cooling residual compression s t r e s s in the flange tips F i g u r e  3.  44 Yielding a t gauge 1C. appears t o have been t o some extent  suppressed and is next evident a t gauge D7 a t s e t  9 and then a t D4 and 8 in t h e following s e t and then a t C 7 and 8 a t s e t 11. • A-s s t r a i n o f t h e specimen is increased i t will be seen t h a t t h e extent o f s t r a i n in the web as a whole is somewhat g r e a t e r than t h e mean s t r a i n in t h e flange t i p s .  A  reversal o f this p a t t e r n must have o c c u r r e d a t some sections where s t r a i n gauges were not p r e s e n t . I t will be seen t h a t a t section D flange tips 1 and 3 do not appear t o enter t h e plastic s t a t e a t any time and eventually a r e v e r s a l o f s t r a i n occurs a t these points with a considerable increase in the strains a t t h e opposite flange tips 5 and 7.  T h i s p a t t e r n corresponds t o the observed  bending o f t h e member about t h e weak axis a t t h e lower end and  which resulted in t h e halting o f t h e t e s t .  of this bending can be seen in t h e s t r e s s - s t r a i n  The effect curve  F i g u r e 5 where a drop in load is evident. T h i s bending may have been t r i g g e r e d by t h e presence of an unusually high upper yield s t r e s s a t flange tips 1 and 3 similar t o t h a t found in coupon 7, F i g u r e l b o r , a l t e r natively, i t may have been t r i g g e r e d by t h e initial elastic strain - pattern. '  45 A. marked d i f f e r e n c e in s t r a i n is evident a t gauges 2 and 6 section D.  In a compression t e s t of this nature i t  does not appear possible t o determine i f this d i f f e r e n c e  may-  have been caused, t o some extent a t l e a s t , by local buckling of the  web.  TABLE COMPRESSION  Set no  Time  «r- mean Initial k.s.i.  u-mean Final k.s.i.  III  TEST  NUMBER 3  Dial Gauges 2 Mean 1  Jg; mean Micro in/in  Temp  Remarks  0 ;p  Specimen  23 M a r c h  0  09.54  0  0  1  10.15  8.51  8.51  2  10.46  17.02  3  11.27  4  11.45  0  0  0  0  70°  11  0.082 0.082 0.082  570  17.02  0.128  0.131  920  ti  25.53  25.53  0.172 0.180 0.176  1220  II  34.04  0.221 0.234 0.227  1580  11  5  25 M a r c h 09.45  33.87  33.56  33.56  0.222  0.235  0.229  1590  68°  6  11.40  35.00  35.00  0.230  0.240  0.235  1630  70°  7  11.56  36.17  36.08  0.236 0.248 0.242  1680  8  13.15  35.96  35.96  0.238 0.248 0.243  1690  9  13.42  37.23  37.11  0.243 0.255 0.249  1730  0.133  " ) ) " )  71°  creep  no  creep  machine stopped  A5  TABLE  III  (continued)  Set no  Time  Initial k.s.i.  o-mean Final k.s.i.  10  14.06  38.30  38.04  0.251  0.264  0.257  1770  11  14.18  37.96  37.91  0.251  0.264  0.257  1770  12  14.32  38.94  38.64  0.258  0.271  0.269  1840  13  14.40  38.53  38.51  0.258  0.271.  0.269  1840  v"  14  14.50  39.45  39.13  0.265  0.280  0.273  1895  "  15  15.00  39.03  38.96  0.265  0.280  0.273  1895  11  16  15.12  40.21  39.51  0.276  0.292  0.284  1950  »  17  15.22  39.40  39.32  0.276  0;292  0.284  1950  "  18  15.33  40.16  39.83  0.295  0.312  0.303  2110  19  15.42  39.79  39.69  0.295  0i3l2  0,303  2110  cr—mean  Dial Gauges Mean 2 1  e„, mean Micro in/in  Temp °F  Remarks  71° ) machine stopped " ) ) machine stopped )  V  ) machine stopped ) ) machine stopped )  71° ) machine stopped " )  S3  TABLE  I I I (continued)  Set no  Time  o- mean Initial k.s.i.  o-mean Final k.s.i.  20  16.16  40.88  39.88  0.335  0.350  0.343  2380  39.69 16.35 26 M a r c h 09.02 39.21  39.62  0.337  0.352  0.345  2400  39.21  0.340  0.354  0.347  2410  21 22  Dial Gauges Mean 2 1 ,  le mean Micro in/in  Temp °F  Remarks  71° ) ) machine " ) ) stopped " )  23  09.41  41.08  2+0.68  0.349  0.364  0.357  2480  "  24  10.00  40.30  40.21  0.351  0.366  0.359  2490  "  25  10.14  41.11  40.11  0.360  0.377  0.369  2560  26  10.48  40.88  39.85  0.374  0.390  0.382  2650  "  27  11.05  39.75  39..69  0.376  0.391  0.383  2660  "  28  11.22  40.68  39.69  0.390  0.406.  0;398  2760  »  29  11.45  39.53  39.39  0.413  0.430  0.421  2920  "  30  13.30  39.19  39.17  0.414  0.430  0.422  2930  :„  ) machine ) stopped ) Max. s t r e s s 41-11 k . s . i . ) ) machine ) stopped  ) ) ) )  machine stopped buckling a t lower end  TABLE  o mean Final k.s.i.  III  Set no  Time  o mean Initial k.s.i.  31  14.30  31.92  31.92  0.380  0.390  32  14.40  21.28  21.28  0.325  33  14.55  10.64  10.64  34  15.15  0  0  (continued)  • Dial Gauges 1 2 Mean  le mean Micro in/in  Temp °F  0.385  2670  71°  0.332  01329  2280  "  0.268  0.270  0.269  1870  "  0.197  0.191  0.194  1350  "  Remarks  unloading  TABLE  III  CROSS  (continued)  SECTION  A  S t r a i n Gauge '. Reading 6 4 5  Set no  1  : 2  3  0  0  0  0  .0  1  285  277  207  2  550  555  3  820  4  7  8  0  0  0  0  270  ' 327  278  280  288  490  551  590  555  560  567  832  775  830  857  837  838  842  1088  1118  1060  • 1135  1118  1117  1099  1120  5  1033  1117  1058  1140  1108  1118  1110  1115  6  1087  1172  1116  1198  1160  1173  1167  1169  7  1115  1209  1155  1230  1185  1206 •  1201-  1202  8  1105  1204  1167  1237  1168  1203  1196  1200  9  1143  1245  1206  1269  1198  1243  1236  1240  10  1175  1285  1260  1305  1211  1269  1268  1274  11  1167  1284  1310  1305  1178  1282  1261  1270  ,  TABLE Set no  1  2  3  I I I (continued) S t r a i n Gauge Reading  4  5  6  7  8  12  1213  1325  1402  1373  1182  1306  1287  1298  13  1194  1330  1437  1397  1163  1306  1393  1328  14  1212  1372  1627  1570  1158  1339  1469  1370  15  1168  1378  1677  1702  1144  1340  1477  1393  16  1162  1429  1830  2102  1130  1385  1535  1404  17  1132  1428  1834  2194  1112  1382  1531  1394  18  1175  1523  1888  2732  1090  1469  1567  1450  19  1177  1534  1868  2807  1080  1473  1560  1444  20  1220  1642  1795  4840  1095  1640  1605  1465  21  1196  1659  1780  4915  1086  1634  1587  1449  22  1178  1650  1743  4940  1077  1633  1583  1434  23  1239  1717  1815  5005  1125  1703  1644  1505  24  1222  1780  1798  4980  1088  1730  1633  1483  TABLE Set no  I I I (continued) S t r a i n Gauge Reading 6 4 5  7  8  1874  1650  1475  1089  1961  1644  1455  5132  1077  1970  1634  1442  1789  5155  1078  2010  1628  1448  " 1915  1772  5155  1063  2046  1630  1438  1210  1915  1770  5158  1065  2051  1632  1438  31  990  1680  1532  4920  837  1817  1392  1202  32  670  1330  1180  4558  502  1468  1038  860  33  350  982  828  4165  170  1150  674  520  34  80  620  457  3732  -126  750  . 265  148  1  2  3  25  1237  1892  1814  5120  1105  26  1225  1908  1793  5143  27  1215  1895  1782  28  1227  1915  29  1210  30  Ul  ro  TABLE  III  CROSS  (continued)  SECTION  B  Set no  1  2  3  4  5  6  7  8  0  0  0  0  0  0  0  0  0  1  278  278  259  259  263  278  300  292  2  563  560  532  532  537  560  577  576  3  838  841  804  800  810  840  892  856  4  1078  1050  1095  1085  1105  1145  1116  1164  5  1057  1158  1090  1089  1106  1152  1093  1158  6  1110  1220  1153  1151  1169  1220  1160  1225  7  1142  1258  1187  1186  1200  1253  1198  126l  8  1142  1253  1287  1285  1192  1260  .1163  1262  9  1176  1296  1225  1222  1227  1304  1168  1315  10  1185  1385  1260  1257  1251  1360  1165  1390  11  1175  1342  " 1255  1250  1243  1367  1148  1371  TABLE  Set no  1  2  3  III  (continued)  S t r a i n Gauge Reading 6 5 4  7  8  12  1198  1376  1285  1278  1265  1415  1167  1383  13  1223  1370,  1280  1272  1260  1426  1160  1382  14  1280  1427  1310  1295  1277  1490  1170  1402  15  1290  1470  1300  1308  1260  1498  1160  1392  16  1364  1566  1315  1345  1267  1564  1170  1413  17  1366  1570  1305  • 1328  1258  1568  1168  1400  18  1446  1720  1312  1348  l'>265  1668  1155  1378  19  1452  1724  1298  1320  1272  1672  1149  1370  20  1578  1926  1242  1273  1215  1787  1156  1363  21  1580  1927  1233  1265  1208  1768  1150  1352  22  1580  1902  1199  1243  1184  1743  1122  1333  23  1644  1980  1225  1300  1175  1834  1180  1392  24  1650  1982  1187  1270  1150  1883  1155  1362  TABLE Set no  I I I (continued)  •  S t r a i n Gauge Reading 6 4 5  7  8  1844  1176  1358  1149  1835 '  1150  1350  1237  1140  1826  1140  1330  1124  1240  1135  1828  1143  1347  2006  1162  1225  1125  1818  1132  1340  1630  2010  1112  1228  1125  1818  1130  1339  31  1390  1763  923  1000  903  1581  892  1100  32  1036  1425  585  665  575  1230  555  748  33  678  1072  250  332  238  879  205  • 392  34  282  • 697  - 77  l  -105  510  -160  25  1  2  3  25  1662  2000  1190  1259  1155  26  1644  2010  1182  1250  27  1632  2000  1170  28  1638  2011  29  1629  30  -  Ul Ul  TABLE  I I I (continued)  CROSS SECTION Set no  1  2  3  0  0  0  0  C  S t r a i n Gauge Reading 6 4 5 0  0  0  7  8  0  0  1  275  270  242  259  266  273  320  300  2  552  565  513  537  545  550  615  572  3  897  852  792  816  806  826  893  849  4  1449  1175  1092.  1115  1080  1135  1181  1217  5  1460  1173  1058  1128  1072  1150  1185  1227  6  1526  1238  1120  1187  1128  1215  1251  1289  7  1560  1278  1159  1223  1138  1253  1289 *  1320  8  1552  1282  .1155  1228  1116  1262  1293  1330  9  1588  1332  1191  1280  1137 .  1313  1357  1382  10  1658  1393  1235  1337  1111  1372  1328  1332  11  1665  1394  1236  1337  1100  1373  1430  1427  TABLE Set no  .III  (continued)  S t r a i n Gauge Reading 6 5 4  7  8  1417  1495  1448  1112  1422  1503 .  1442 '  1420  1130  1490  1589  1475  1350  1416  1120  1485  1608  1477  1705  1378  1425  1122  1540  1742  1552  1846  1711  1373  1418  1114  1532  1755  1545  18  1930  1848  1382  1433  1075  1610  1940  1613  19  1930  18-55  1376  1428  1066  1609  1945  1617  20  1975  2142  1388  1432  1084  1652  2505  2351  21  1962  2137  1377  1425  1080  1690  2528  2365  22  1942  2110  1348  1407  1065  1678  2510  2359  23  1982  2176  1400  1465  1125  1748  2690  2442  2k  1921  2156  1362  1440  1112  1732  2718  2468  1  2  3  12  1730  1435  1280  1377  1115  13  1729  1435  1287  1382  1778  1489  1353  15  1774  1528  16  1847  17  14  :  TABLE  Set no  -  I I I (continued)  S t r a i n Gauge Reading  1  .2  3  4  5  6  7  8  25  1834  2162  1332  1439  1120  1747  3018  2615  26  1758  2690  1237  1444  1148  1811  3238  2704  27  1740  2722  1224  1433  1145  1815  3250  2710  28  1695  3187 •  1200  1440  1153  1899  3443  2835  29  1615  3575  1172  1425  1145  2085  3772  2998  30  1613  3635  1170  1425  1140  2108  3782  3005  31  1387  3410  960  1205  917  1886  3538  2772  32  1035  3052  635  865  578  1547  3173  2415  33  667  2685  298  522  235  1195  2804  2043  34  253  2278  - 50  177  -113  823  2390  1627  OO  TABLE  III  CROSS  (continued)  SECTION  D  S t r a i n Gauge Reading  Set no  1  2  3  4  5  6  7  8  0  0  0  0  0  0  0  0  0  1  260  283  111  250  392  278  357  310  2  548  573  378  530  685  553  638  595  3  830  862  660  810  960  828  910  882  4  110 '  1180  961  1099  1220  1117  1242  1193  5  1165  1165  965  1108  1241  1130  1280  1205  6  1220  1224  1000  1127  1275  1188  1343  1261  7  1252  1269  1018  1239  1272  1236  1380  1292  8  1253  1263  1030  1239  1252  1241  1370  1293  9  1288  1310  1089  1289  1289  1298  1440  1348  10  1272  1368  1129  1408  1310  1390  1551  1435  11  1260  1369  1128  1422  1308  1398  1540  1440  TABLE Set no  I I I (continued) S t r a i n Gauge Reading  1  2  3  4  5  6  7  8  12  1259  1446  1152  1520  1340  1465  1585  1500  13  1245  1450  1151  1550  1333  1473  1587  1500  14  1272  1505  1168  1765  1350  1556  1622  1498  15  1270  1503  1163  1794  1347  1571  1619  1492  16  1286  1732  1174  2028  1374  1680  1665  1470  17  1283  1747  1160  2058  1370  1689  1649  1465  18  1272  2330  1182  2685  1457  1914  1778  1490  19  1268  2445  1180  2722  1452  1934  1778  I486  20  1077  5937  1180  6102  2727  3158  1930  1499  21  1052  6058  1178  6185  2837  3198  1916  1500  22  1032  6196  1165  6198  2880  3205  1917  1485  23  1075  6152  1198  6260  3170  3268  1972  1535  24  1069  6147  1166  6243  3186  3261  1970  1508  TABLE  Set no  III (continued)  1  2  3  4  5  6  7  8  25  1046  6122  1144  6270  3442  3250  1939  1515  26  960  6128  1076  6522  4687  3271  1996  1573  27  940  6122  1062  6562  4796  3266  2015  1572  28  790  6205  955  7132  5932  3289  2314  1710  29  552  7964  722  8274  7360  4410  3240  4360  30  544  8092  707  8325  7435  4485  3280  4405  31  328  7855  492  8090  7182  4267  3005  4170  32  20  7470  192  7714  6758  3918  2607  3810  33  -283  7060  -100  7310  6304  3560  2183  3434  -630  6583  -420  6825  5765  3148  1728  3014  34  .  62 Conclusions; The  following  conclusions are  drawn from  these  tests:  i - Y i e l d i n g f i r s t d e v e l o p s a t a f l a n g e t i p . T h i s is s h o w n by t h e f o l l o w i n g t a b u l a t i o n o f t h e f i r s t o b s e r v e d i n d i c a t i o n s of. y i e l d i n g . Test  No  1 2 3  Set  7 6 4  Gauge  3 D7  Cl  T h i s l o c a t i o n o f f i r s t yielding is in a g r e e m e n t w i t h t h e a s s u m e d cooling r e s i d u a l s t r e s s pattern • F i g u r e 3. • ii -  S u b s e q u e n t d e v e l o p m e n t o f yielding is v e r y i r r e g u l a r and v a r i e s f r o m s e c t i o n t o s e c t i o n and e v e n a t a d j a c e n t l o c a t i o n s on t h e s a m e c r o s s sections. A t no gauge l o c a t i o n does yielding p r o c e e d d i r e c t ly t o s t r a i n h a r d e n i n g as s u g g e s t e d by T h u r l i m a n n ? T h e a b o v e c o n c l u s i o n may be r e a d i l y confirmed., by an e x a m i n a t i o n o f F i g u r e s 7, 9, 10 and 12.  iii - A r e s i d u a l c o m p r e s s i o n s t r e s s is p r e s e n t in t h e s e c t i o n . T h i s c o n c l u s i o n is e v i d e n t f r o m d i a g r a m s s h o w n in F i g u r e 5.  of  at least 6  the  k.s.i.  stress-strain  CHAPTER  BENDING  General  IV  TESTS  Description T w o series o f bending t e s t s were made t o investigate  the behaviour of a critical length of a 5" x 5 " x l 6 l b  W.F.  Type A 3 6 steel beam subjected t o bending moments in the plastic range. The  critical length is defined in the Commentary as o  the " c r i t i c a l unsupported length f o r lateral buckling"  A  simplified expression f o r the evaluation of this length is given in the Commentary and this length f o r t h e above member, when subjected t o a uniform to  plastic moment was found  be 2+1+.3"  9  The  adequacy o f the section with regard t o pre-  mature local buckling was checked as described in t h e Com1 D mentary and was found t o be- s a t i s f a c t o r y . The Figure l a .  f i r s t series o f t e s t s were made on member A 5 , ' T h i s member had previously been axially loaded  as described in C h a p t e r I I I .  T h e object o f this loading was  the removal of both the upper yield point and t h e residual stresses.  T h i s , f o r reasctas described in the previous  64  chapter, was  not achieved.  I t was  then hoped to compare  the performance of a critical length of this pre-loaded  mem-  ber in bending in the plastic range with the performance of a similar but not pre-loaded  member.  T h i s second series of  t e s t s were made on member AJ+ Figure l a , which had  not  been subjected to previous loading. A l l the bending t e s t s were carried out using the .Tin'us Olsen machine. of the dial and  The  method o f loading and the location  s t r a i n gauges are shown in Figure  13.  A l l the electric s t r a i n gauges used were Philips 9814  and  PR  were a t t a c h e d to the member by means of E a s t m a n  •910 cement.  The  gauges were connected through the  switch-  ing and balancing units described in C h a p t e r I to a Budd Model HW-1 The  s t r a i n indicator. method of observing the lateral displacement  the beam at mid  of  span consisted of a s h o r t aluminum rolled  section placed in c o n t a c t with the beam and f r e e t o slide laterally on the loading p l a t f o r m of the t e s t i n g machine. The  lateral movement of the aluminum section was  by a dial gauge.  measured  T h i s method proved to be u n s a t i s f a c t o r y  since i t presupposes that' the aluminum section will at all times remain v e r t i c a l and in c o n t a c t with the t e s t beam.  65 T h i s did not appear t o be the case.  Ideally, a t least t w o  dial gauges should have been used so t h a t both l a t e r a l displacement and toxrs-i*o:i3i of the t e s t beam could have been detected. In the l a t t e r p a r t s o f Bending T e s t angular displacement  Number 2 the  o f the t o p flange f r o m the horizontal,  at mid span, was measured instead of the lateral displacement. An  examination o f the as rolled section revealed t h a t  the web was not normal t o t h e flanges which were consequently displaced laterally by about 0.125",  Figure 14.  T h i s d e f e c t did not appear t o influence t h e performance o f the member in bending. i Bending T e s t The  Number 1  r e s u l t s of bending t e s t number 1, made on  specimen A 5 are given in Table I V and a r e shown graphically in F i g u r e 16 and 1 7 . T h i s t e s t consisted o f t w o p a r t s .  In t h e f i r s t  p a r t o f the t e s t t h e member was loaded t o failure  with  s t r a i n gauges 1, 11 and 12 on t h e t o p of a compression flange.  In the second p a r t o f the t e s t t h e member was  f i r s t straightened, by using the t e s t i n g machine as a p r e s s ,  66 and was then reloaded t o failure in t h e opposite "direction with s t r a i n gauges 1, 11 and 12 on t h e bottom o r tension flange. A i l gauge readings were taken with t h e machine stopped f o r each s e t .  Some o f the final s t r a i n gauge read-  ings were o f f scale on the indicator and were t h e r e f o r e ' not recorded, f o r example gauges 6 and 7 a t mid span f o r s e t 36.  T h e d i f f e r e n c e between t h e initial and final moments  in each s e t is due t o creep only. A l l electric s t r a i n gauge readings in Table I V are r e f e r r e d t o t h e initial zero readings..  F i g u r e 17 has how-  ever been plotted with t h e s t r a i n s r e f e r r e d t o zero f o r t h e r e - s t r a i g h t e n e d beam. Approximate t h e o r e t i c a l s t r e s s diagrams  correspond-  ing t o a mean yield s t r e s s of 38.3 k . s . i . are shown f o r r e f e r e n c e in F i g u r e 16. ' T h e fully developed  plastic moment corresponding to  the above mean yield s t r e s s f o r this section is 368 kip inches and the equivalent maximum elastic moment is 326 kip inches. An  examination of the r e s u l t s f o r the f i r s t  part of  this t e s t reveals t h a t t h e r e is a considerable divergence in  67 the s t r a i n p a t t e r n f r o m the theoretical linear distribution, and t h a t only a t mid span is t h e r e evidence, just prior t o failure, o f a fully developed plastic moment. A.s the deflection o f t h e member is increased i t will be seen t h a t the s t r a i n p a t t e r n s become very irregular and consequently  difficult to interpret.  A t section B Figure 16  there is evidently lateral buckling in t h e compression flange with g r e a t l y increased compression strains a t flange tip no. 1 and a corresponding 11.  reduction in s t r a i n a t flange t i p no.  Failure of the member occurred, a f t e r very  able v e r t i c a l deflection,  consider-  by local buckling a t flange t i p no. 1  just beyond the load point near section B , where maximum shear and near maximum moment were p r e s e n t .  T h e loca-  tion and type of this failure is shown in Figure 15. In the second p a r t o f t e s t number 1, F i g u r e 17, i t will be seen t h a t a similar buckling o f t h e compression flange occurred a t section B but in this case t h e r e was a greatly increased compression s t r a i n a t flange tip no. 5 and a corresponding  reduction a t flange t i p no. 7.  T h e mode  and type of failure in this p a r t o f t h e t e s t was almost identical with t h a t already described and shown in F i g u r e 1$ except t h a t in this case failure occurred a t flange t i p no. 5.  68 The was  r e s u l t s of these t w o t e s t s indicate t h a t t h e r e  no significant d i f f e r e n c e in the maximum moment a t  which failure occurred but t h a t in the second t e s t  failure  occurred a t a considerably smaller v e r t i c a l deflection than t h a t a t failure in the f i r s t The  test.  development a t gauges 3 and 9 o f tension strains  in the f i r s t p a r t o f the t e s t and compression s t r a i n s in t h e second p a r t of t h e t e s t indicate t h a t flange 1 1 , 1 2 , 1, is s t r o n g e r than flange 5, 6, 7.  TABLE BENDING Set no  Initial Time Moment kip ins. :n  1  Temp °F  Dial B O  Dial (£ S  IV  T E S T NUMBER Dial C O  Dial <£ O*  Final Moment kip ins  Time  1:  29-3-63 13.45  1  70°  0  0  0  0  0  Remarks  Specimen A5 See F i g u r e 16  2  44  14.05  0.122  0.139  0.120  0.012  44  3  88  14.10  0.240  0.275  0.239  0. 020  88  4  132  14.19  0.365  0.419  0.364  0.026  132  5  176  14.31  »  0.492  0.567  0.494  0.034  176  6  220  14.40  »  0.627  0.725  0.635  0.037  220  7  264  14.53  »  0.771  0.893  0.715  0.041  263  8  308  15.08  1.154  1.181  1.163  0.047  306  15 .15  9  352  15.30  71°  1.349  1.417  1.373  0.061  346  15 .40  10  346  15.45  it  1.349  1.417  1.373  0.061  345  11  -  1  10 9 7 8  2  0  2 3 4  l  5  creep  ) machine stopped ) creep only ) 0> vO  TABLE  Set no  Initial Moment kip ins  11  363  16.00  12  356  13  IV  (continued) Final Moment kip ins  Time  Remarks  Dial B 6  Dial $ 6  Dial C 6  Dial £ O  71°  1.532  1.633  1.556  0.087  16.07  it  1.532  1.634  1.557  0.087  363  16.20  it  1.560 . 1.667  1.585  0.089  14  359  16.25  it  1.560  1.667  1.585  0.089  15  368  16.35  it  1.615  1.734  1.640  0.095  16  360  1.615  1.735  1.640  0.095  359  17  355  ti 16.40 30-3-63 09.25 68°  1.615  1.735  1.640  0.096  355  18  368  09.39  1.655  1.780  1.679  0.098  368  09.46  19  372  09.50  tt  1.673  1.800  1.695  0.098  367  20  365  10.10  tt  1.675  1.801  1.694  0.104  365  0 9 . 5 9 ) machine stopped ) creep delayed 10.18 ) 5 min.  21  372  10.21  It  1.698  1.833 •  1.720  0.100  22  366  10.30  1.696  1.834  1.719  0.101  365  ) ) machine 10.38 ) stopped  Time  Temp op  11  ) machine ) stopped ) ) •) machine ) stopped  . 348  ) machine ) stopped ) overnight  -<3 O  TABLE  Set no  Initial Moment Time kip ins  23  372  IV  (continued)  Dial B O  Dial Ct 6  Dial C 6  Dial  op  68°  1.732  1.868  1.748  0.102  366  Temp  O  Moment kip ins  Time  Remarks  24  366  10.50  tl  1.732  1.868  1.748  0.102  365  10.48 ) ) machine 10.57 ) stopped  25  372  10.59  69°  1.763  1.905  1.777  0.103  366  11.07  26  372  11.09  ti  1.809  1.940  1.805  0.103  366  27  372  11.33  tt  1.841  1.976  1.838  0.103  366  11.40  28  372  11.45  II  1.936  2.095  1.934  0.104  365  11.55  29  372  12.05  it  2.063  2.256  2.061  0.105  366  30  363  tt  2.063  2.256  2.061  0.105  363  31  362  15.50 1-4-63 09.05  68°  2.063  2.257  2.061  0.105  362  12.15 ) ) machine ) stopped ) 45 hours )  32  375  09.42  It  2.103  2.305  2.100  0.105  375  09.45  33  376  09.47  II  2.108  2.314  2.107  0.105  376  10.40  -  no creep no creep  ^3  TABLE  Set no  Initial Moment kip ins  Time  Temp Dial B °F 6  IV  (continued)  Dial (b  Dial C  Dial O  6  373  10.50  68°  2.110  2.315  2.108  0.105  35  369  11.00  II  2.207  2.691  2.195  0.075  36  368  11.42  69°  3.028  4.060  2.927  0.020  37  0  1.838  2.889  1.720  0.025  38  0  39 40  34  41  13.10  68°  374  14.35  n  377  15.00  II  15.28  II  0  2-4-63 68° 09.10  0  43  110  09.52  44  220  10.12  Remarks Max  moment  .381 F a i l u r e , see Figure 15 Unloaded Re-loaded 0.1"/min  Beam straightened P.M.  42  Final Moment Time kip ins  1st A p r i l and reloaded in opposite direction 2nd A p r i l  0"  0"  0"  0"  II  0.297  0.338  0.297  .0  II  0.599  0.682  0.598  0.003  See  Figure  17  TABLE Set no  Initial Moment kip ins  45  330  46  Time  T e m p Dial B 6 °F  IV  (continued)  Dial Cfc  Dial C 6  D i a l (£ O  10.55  68°  0.915  1.052  0.916  0.009  352  11.06  it  1.017  1.168  1.017  0.012  47  363  11.18  69°  1.116  1.278  1.113  0.018  48  368  11.30  it  1.296  1.504  1.297  0.033  49  362  11.45  ti  1.453  1.682  1.444  0.033  50  372  12.05  ti  1.708  1.983  1.692  0.022  51  356  13.07  70°  1.708  1.983  1.692  0.022  52^  0  13.24  ti  53  0  Final Moment kip ins  Time  Remarks  5 1  1  4 8 3 9 2 10 12  7 11  L o a d f e l l 120 lb Failure  Beam r e straightened  TABLE  IV  (continued)  SECTION Set no  Moment kip in.  1  B  S t r a i n Gauge Reading  1  2  3  4  5  6  7  8  9  10  11  12  0  0  0  0  0  0  0  0  0  0  0  0  -  -  +  +  +  +  +  +  +  -  -  -  2  44  185  87  0  92  164  175  163  89  4  86  132  129  3  88  350  169  7  183  315  338  328  185  7  166  271  342  4  132  510  245  25  297  469  500  492  293  19  243  415  515  5  176  670  323  40  415  615  655  650  407  36  321  560  682  6  220  830  399  65  551  762  815  799  540  60  394  707  853  7  997  470  100  709  906  968  942  693  94  471  857  1029  8  1172  543  145  886  1047  1118 1075  865  136  542  1013  1209  9  1477  ,595  265  1226  1142  1173  1147  1208  276  599  1172  1397  1504  590  280  1234  1130  1157  1132  1217  282  595  1165  1335  10 11  346  TABLE Set no  Moment kip in  IV  (continued)  S t r a i n Gauge Reading 6 5 4 7  8  9  10  11  12  1137  1612  427  727  1242  1375  1097  1145  1667  444  739 . 1255  1362  1292  1080  1138  1797  479  784  1259  1635  1729  1271  1060  1121  1793  474  784  1241  1638  460  1762  1323  1117  1168  1825  478  807  1284  1689  833  485  1824  1387  1138  1137  1855  492  807  1282  1704  3533 -  829  481  1834  1382  1113  1130  1855  487  805  1269  1687  22  3571  838  483  1863  1404  1115  1146  1871  491  814  1277  1686  23  3722  855  485  1884  1419  1125  1141  1890  492  832  1277  1699  24  3782  855  490  1882  1410  1111  1136  1890  494  826  1267  1691  1  2  3  356  2958  769  413  1584  1252  1090  359  3080  757  425  1632  1266  16  360  3447'  815  457  1739  17  355  3480  816  455  18  368  3534  840  19  372  3554  20  365  12 1314 15  21  TABLE Set no  Moment kip in  -  IV  (continued)  S t r a i n Gauge Reading  1  2  25  3942  26  3  4  5  6  7  8  9  10  11  12  877  495 1904 1419 1130 1140 1915  504  900 1267 1681  .4367  900  503 1924 1416 1140 1135 1940  515  877 1261 1699  27  4612  931  507 1950 1420 1163 1130 1973  522  897 1262 1772  28  5650 1070  517 2079 1404 1195 1087 2124  539 1017 1233 1957  29  7022 1230  555 2316 1410 1245 1090 2345  584 1167 1202 2280  7113 1249  532 2301 1374 1220 1070 2333  579 1187 1187 2287  7177 1278  558 2344  581  30  31  362  32  375  33  1439  1291  1137  2370  1217  1239 2351  TABLE Set no  Moment kip in  -  IV  (continued)  S t r a i n Gauge Reading  1  2  —  —  3 +  4  5  6  7  +  +  +  +  8  9  10  11  —  —  12  2371  580 1242 1191 2332  1356 1065 3041  686 1915 1104 2784  +  +  34  373  7182 1297  555  2344 1420 1260  35  369  8782 2095  618  2872 1370  36  367  10831 3065  37  0  9208 2301  695  3299  241  225  - 12 3645  822 1920 +253 2661  38  0  9208 2301  695  3299  241  225  - 12 3645  822  39  366  12324  3843  578  4324  40  364  13310 4685  570  4902 1776 3693 3595 5312  41  0  11397 3895  527 4059  —  —  745 4140  +  +  1125  1544 1685 1290  4471  1596 2751 +2464 4708  286 2187 2320  —  —  —  4485  836 2691  924  1920 253  4171  2661  744 3135 -583 4935 824 3540  382 5862  811 2765 +518- 4122  +  +  +  +  +  83 308  613  42  0  3019  285  293  355  596 2230  127  720  446  43  110  2557  10  285  140 1014 2653  489  505  449  297 638 1043  44  220  2087 +223  287  -84 1441 3095  850  277  452  525 993 1491  TABLE Set no  Moment kip in  IV  (continued)  S t r a i n Gauge Reading  1  2  3  4  5  6  7  8  9  10  11  12  45  330  1580  2+80  287  340  1911  3599  1215  23  454  775 1368  1988  46  348  1354  583  278  456  2040  3807  1279  - 82  450  873 1453  2175  47  357  1129  693  261  600  2150  4137  1305  212  437  971 1525  2363  48  360  987  993  165  1069  3281  4930  1129  628  399  1260 1598- 2955  49  362  992  1305  93  1429  5906  5685  953  995  390  1363 1700  3503  50  360  1015  1637  - 57  1971 10537  6707  679  1500  339  1911 2250  4097  51  356  1024  1647  60  1976 10586  6714  665  1505  338  1918 2251  4097  52  0  2606  851  36  1169  8633  5095  +280  705  336  1138 1061  2533  53  0  4221  90  + 135  109  5431  2980  420  303  +  462  473  703  1093  -Or Co"  TABLE  IV  (continued) cj:  SECTION Set no  Moment kip in  1  2  3  4  1  0  0  0  0  -  -  S t r a i n Gauge Reading  5  6  7  8  9  10  11  12  0  0  0  0  0  0  0  0  0  +  +  +  +  +  +  +  -  -  -  •J2  44  118  83  5  90  151  180  181  91  1  90  150  173  3  88  328  158  18  186  304  343  363  114  10  174  295  341  i-36  285  464  513  558  285  22  257  444  407  4  132  488  228  5  176  647  300  56  390  654  684  753  390  37  337  592  673  6  220  810  368  83  500  843  856  96l  498  55  417  740  840  980  435  120  625  1063  1036  1165  619  83  494  890  1008  7 8  1162  500  159  757  1316  1216  1373  748  120  572  1042  1178  9  1355  540  268  995  1853  1346  1633  988  217  624  1206  1341  1354  535  275  1005  1873  1346  1623  993  221  622  1202  1335  10  346  TABLE Set no  Moment kip in  IV  (continued)  S t r a i n Gauge Reading 6 4 5 7  8  9  10  11  12  2438  1316  360  657  1297  1387  1583  2549  1348  370  672  1317  1399  4821  1666  2799  1402  385  728  1362  1392  1438  4953  1715  2681  1390  380  729  1345  1379  440  1458  5009  1772  2731  1419  381  756  1390  1430  690  451  1495  5621  1818  2704  1436  392  76l  1392  1433  2702  690  458  1515  6003.' I860  2787  1459  401  759  1384  1423  22  3267  735  460  1570  6064  1964  2815  1513  403  800  1382  1438  23  3434  767  456  1605  6160  2018  2900  1498  405  826  1382  1463  24  3454  770  456  1608  6164  2018  2905  1498  403  826  1374  1440  1  2  3  356  1775  582  415  1320  3936  1566  359  ' 1825  6 00...  425  1355  4043  16  360  2228  660  443  1446  17  355.  2255  665  438  18  368  2305  689  19  369  2438  20  365  12 13 14 15  p1  TABLE Set no  IV  (continued)  Moment kip in  1  2  3  4  5  6  7  8  9  10  11  12  857  1382  1443  25  3500  810  458  1650  6210  2028  2996  1580  ' 403  26  3516  850  458  1685  6266  2093  3108  1613  405  892  1394  1437  27  3555  895  472  1725  6366  2300  3206  1653  417  919  1402  1438  28  3828  1022  540  2027  7112  2299  3728  1968  487  1027  1407  1432  29  3944  1240  595  2315  7550  2456  4565  2238  537  1255  1419  2800  3954  1283  590  2300  7525  2428  4483  2240  535  1300  1409  2833  3970  1324  593  2338  7588  2503  4541  2278  531  1345  1475  2903  30 31  362  32  375  33 "  TABLE  Set no  Moment kip in  1  2  3  -  -  +  588  34  373  3926 1384  35  368  4317 3628  36  367  IV  (continued)  S t r a i n Gauge Reading 6 4 5 7 .+  +  +  +  8  9  10  11  12  +  +  . -  -  -  525  1396 1496  3442  2370  7595  2501  4578 2304  1140  4743.  9200  5990  4813  3983 4325  1605  6625 9983  970 3857  3043  10031  6488  1084 5387 6352 12471  37  0  2706  3870  1510  5695 8422 6651  6979  5592  1043  4536 4743  38  0  2706 3870  1510  5695 8422 6651  6979  5592  1043  4536 4743 10813  39  366  4052  4080  1628 6687 9997  6548  1107  5416 6342  12516  40  364  4022  4652  1650  6780  6617  1085  5495 6538  12614  0  2743  3950  1540  5880 8569 6970  5753  1053  4675 5048  11035  +  —  41  42  0  1260  215  +  +  10148  +  655 1318 2218  —  212  +  +  +  393  1220  539  —  +  10813  —  28 1002 2588  TABLE Set no  Moment kip in  IV  (continued)  1  2  3  4  5  - 6  7  43  110  1682  + 15  642  1095  1838  640  5  44  220  2105  235  627  863  1417  1090  -402  45  329  2560  362  607  618  950  1602  857  46  347  2757  525  590  510  768  1832  47  357  2965  625  570  383  583  48  359  3632  915  528  60  49  360  4425  1108  510  50  : 359  5068  1310  51  356  5057  52  0  53  0  8  9  10  11  12  542  +200 1376  2153  770  545  446 1790  1696  510  545.  720 2263  1178  1101  393  535  878 2448  953  2084  1381  256  : 517  961 2641  690  444  2589  2064  129  470  1326 2858  187  -127  367  2877  2547  349  449  1554 2924 . +127  460  354  286  3219  2990  605  412  1823 3042  454  1307  460  358  292  3208  2981  612  410  1830 3038  455  3585  562  518  +447  1720  1642  1595  + 190  405  984 1596 -1128  1935  - 90  670  1308  2885  + 58  +203  1108  517  174  1003  ;  438  2741 Go CO  TABLE  IV  (continued)  SECTION  C  Set no.  Moment kip in  S t r a i n Gauge Reading 1  2  3  4  5  6  7  8  9  10  11  12  1  0  0  0  0 +  0 +  0 +  0 +  0 +  0  0  -  0 +  0  -  0 +  -  -  -  91.  0  90  164  174  2  44  153  77  3  97  132  180  192  3  88  312  145  14  201  285  345  384  196  12  170  304  340  4  132  470  209  36  328  452  514  565  325  36  250  456  510  5  176  630  270  66  464  662  682  742  470  65  322  6Q7  680  6  220  792  325  106  626  775  851  925  648  110  390  762  854  7  965  377  l6l  815  944  1023  1098  860  168  460  920  1039  8  1150  425  231  1042  1118  1195  1262  1120  240  525  1084  1237  9  1415  437  404  1440  1332  1287  1413  1615  410  562  1254  1470  1415  435  411  1443  1330  1282  1407  1620  412  560  1254  1468  .0  346  11 ]  OO -P5  TABLE Set no 12  Moment kip in  IV  (continued)  S t r a i n Gauge Reading 6 7 4 5  8  9  10  11  1426  2118  565  602  1439  1552  1261  1439  2118  573  618  1477  1576  1  2  3  356  1629  465  581  1846  1403  1257  359  1650-  477  596  1880  1422  12 .  13 14 15  -  16  360  1675  504  624  1975  i486  1252  1425  2290  595  655  1543 ' 1635  17 '  355 •  1667  504  626  1962  1473  1287  1406  2280  590  660  1543  1629  18  368  1715  526  629  1992  1524  1290  1455  2308  591  686  1595  1677  19  368  1700  529  631  1993  1521  1285  1455  2310  593  688  1584  1682  20  365  1685  522  633  1990  1517  1280  1455  23'08  595  682  1576  1672  22  1694  527  638  2000  1538  1282  1448  2316  600 . 688  1594  1669  23  1700  541  636  2005  1546  1236  1451  2320  596  700  1625  1677  24  1690  539  638  2000  1536  1284  1445  2320  596  702  1622  1672  21  1  TABLE Set no  Moment kip in  IV  (continued)  S t r a i n Gauge Reading  1  2  3  4  8  9  10  25  1700  547  646  2332  600  710  1645 1692  26  1702  554  652 2032  1565 1278  1430 2353  605  720  1707 1692  27  1690  570  656 2052  1610 1275  1428 2382  605  744  1712 1728  28  1670  627  692 2262  2862 1258 1415 2612  628  812 1857 1984  29  1692  745 -748 2552  4545  1310 1445 -2950  670  950 2047  2454  1680  745  4442  1295 1433  2938  665  958 2029  2447  1736  772  1405 1506 2994  673  987 2088  2520  5  6  7  2016 1550 1295 1442  11  12  30  31  362  32  375  33  .754 2535  763 2.596 4782  TABLE  Set no  Moment kip in  IV  (continued)  S t r a i n Gauge Reading  1  -  2  -  3  4  5  6  7  8  9  +  +  +  +  +  +  +  10  -  11  12  -  -  34  373  1720  765  779  2670  5069  1423  1475  3035  693  985 2071  2522  35  368  3787  1186  86l  3208  5287  1530  2890  2657  768  1530 2002  2712  36  367  6872  1713  986  3914  4325  1930  1060  4396  885  3829 2172  3284  37  0  5468  1042  941  3036  3082  475  566  3570  850  1251  759  1781  38  0  5468  1042  9941  3036  3082  475  566  3570  850  1251  759  1781  39  365  6825  1747  1001  3962  3619  i960  887  4446  880  2079 2336  3381  40  364  6538  2059  966  4140  3467  3070  827  4550  793  2383 3524  3967  41  0  5273  1393  911  3267  2629  1550  482  3744  765  1609 1952  2463  0  +  +  +  +  +  -  -  +  +  0  446  773  651  390  1106  2385  1612  453  494  42  +  +  770 2100  1635  +  03  TABLE  Set no  Moment kip in  IV  (continued)  S t r a i n Gauge Reading  1  2  43  110  860  970  44  220  1275  1168  45  329  46  3  4  5  6  7  8  9  11  12  988 2480  2062 2503  10  160  924 2815 1735  240  490  659 - 77  748 3256 1858  17  483  1216  2896  1728 1395  648  340  567 3748 1996 -236  477  1465  3361 2991  346  1915 1473  623  450  530  3950  2118  350  465  1551 3525  47  356  2200  1556  596  597  519  4213  2227  514  435  1640  3655 3348  48  359  3150  1793  559  924  539 4834 2408  870  384  1733  3768  49  360  3568  1943  546  1092  594 5355 2515  1068  353  2006  3850 4060  50  359  3963 2158  492  1452  727 6150  2665  1480  256  2235  3893 4578  51  356  3965 2160  481 1460  725 6153 2600  1485  253  2235  3888 4576  52  0  2575 1471  498  635  2162  704  265  1447  2425  53  0  1417  636  252 1287 2810 1368  233  425  913  659  1240  4590  3165  3748  3048  755 1338 1811 03  00  89 Bending T e s t Number 2 The  r e s u l t s o f bending t e s t number 2 made on spec-  imen A 4 a r e given in Table V and a r e shown graphically in F i g u r e s 18 and 19. T h i s t e s t was conducted  in t h r e e p a r t s .  In the  f i r s t p a r t o f the t e s t the member was loaded t o failure with s t r a i n gauges 1, 11 and 12 on the t o p or compression In  the second  flange.  p a r t o f the t e s t t h e member was f i r s t  straightened, by using the t e s t i n g machine as a p r e s s , and was then re-loaded t o f a i l u r e in the opposite direction with s t r a i n gauges 1, 11 and 12 on the bottom o r tension flange. In  t h e t h i r d t e s t the specimen was again straightened and  re-loaded in the same direction with s t r a i n gauges 1, 11 and 12 on the bottom or tension flange. A l l gauge readings were taken with the machine for  stopped  each s e t and a r e r e f e r r e d t o t h e initial zero readings.  Figure 19 has, however, been plotted with the strains r e f e r r e d t o zero f o r the r e - s t r a i g h t e n e d beam. Approximate theoretical s t r e s s diagrams corresponding to  a mean yield s t r e s s o f 37.3 k . s . i . a r e shown f o r r e f e r -  ence in F i g u r e 18. The  fully developed  plastic moment corresponding t o  the above mean yield s t r e s s f o r this section is 358 kip inches  90 and the equivalent maximum elastic moment is 310 kip inches. As  a f u r t h e r aid t o f a c i l i t a t e the study o f the  development o f yielding, the member was painted prior t o loading with a s t r e s s sensitive paint. and  T h i s paint was old stock  was not applied in accordance with the m a n u f a c t u r e r s  rigid specifications, nevertheless, r e s u l t s were obtained indicating t h e development o f lateral buckling in t h e t o p flange.  T h e yield p a t t e r n indicated by this method f o r s e t  number 12 is shown in F i g u r e 2 0 c .  T h e subsequent develop-  ment of lateral buckling is evident in the s t r a i n p a t t e r n s in Figure 18, which shows the s t r a i n p a t t e r n f o r t h e f i r s t p a r t o f the t e s t . mid  T h e r e s u l t a n t t w i s t i n g of the section a t  span a t failure is shown in Figure 20a.  No check was  made a t failure t o determine i f any change in t h e geometry of t h e c r o s s section of the member had o c c u r r e d . The  s t r a i n p a t t e r n s f o r t h e second p a r t o f the t e s t  are shown in F i g u r e 19 and t h e c r o s s section a t mid span at failure is shown in Figure 20b. T h e torsional buckling o f the member is evident in the s t r a i n p a t t e r n s .  A n unusual  f e a t u r e o f the above p a t t e r n s i s , that despite t h e considerable d i f f e r e n c e in the deflection of t h e member a t s e t s 43 and  54, no comparable d i f f e r e n c e is evident in t h e s t r a i n  patterns.  91 A  f u r t h e r f e a t u r e o f this t e s t is the significant  regain in s t r e n g t h following a period during which t h e machine was  stopped and t h e member maintained a t a near  deflection.  F o r example, f o r s e t s number 37 t o 42 inclusive  the maximum moment was within the range and by  363-368  kip inches  during this period the mid span deflection was increased  1".269.  p.m. on  T h e machine was stopped a t approximately  20th  42 and  A p r i l t o r e c o r d s e t number  stopped until s h o r t l y a f t e r The  constant  09.45  a.m. on t h e  12.35  remained  22nd  April.  moment had in this interval, due t o creep, dropped by  11 kip inches t o 357 kip Inches.  Re-loading  was then com-  menced a t a very slow r a t e and was stopped immediately the f i r s t 20 lb drop was observed in the load. load occurred  T h i s drop in  a t a moment o f 387 kip inches.  increase in vertical deflection o f only  0".121.  Following an Subsequent  cycles o f r e s t i n g and re-loading resulted in an increase in the maximum moment t o 398 kip inches.  T h i s o c c u r r e d in  spite o f a f a i r l y considerable t w i s t i n g o f the member.  TABLE BENDING  Set no  1 2  Initial Moment Time kip ins  0  Temp °F  19-4-63 10.50  69° .  V  TEST  '  NUMBER  Dial B O  Dial O.  Dial C  0  0  0  0  0.121  0.239  0.120  0.006  6  Dial (£ O  44.5 11.00  » »  0.224  0.371  0.235  0.026  »  0.350  0.500  0.348  0.036  0.465  0.632  0.434  0.038  0.586  0.767  0.580  0.047  2 Final Moment kip ins  Time  Specimen A2+ See F i g u r e 18  11  88  11.10  4  132  11.16  5  176  11.24  6  220  11.31  7  264  11.43  0.704  0.907  0.704  0.057  8  308  11.58  1.115  1.146  1.125  0.069  307.5  12.07  9  352  12.08  »  1.280  1.328  1.282  0.078  346  12.15  :. 3.43  13.12  70°  1.280  1.329  1.278  0.078  343  10  »  12 10 9 8  3  •  Remarks  .1 2 3 4  ) machine ) 13.20 ) stopped  ro  TABLE  Set no  Initial Moment kip ins  Time  Temp °F  V  (continued)  Dial B  Dial Cfc  6  6  Dial  6  C  Dial <£  Final Moment kip ins  Time  11  352  13.22  70°  1.308  1.362  1.311  0.083  350  13.28  12  363  13.31  n  1.392  1.460  1.392  0.093  354  13.38  13  367  14.30  ti  1.502  1.592  1.498  0.106  357  14.40  14  369  14.42  n  1.618  1.731  1.614  0.117  360  14.50  15  371  14.53  it  1.758  1.900  1.754  0.139  361  15.01  16  358  15.50  71°  1.758  1.900  1.754  0.142  358  15.58  17  373  16.00  II  1.923  2.100  1.918  0.162  362  16.10  18  374  16.14  it  2.088  2.300  2.088  0.187  363  16.24  19  373  ti  2.253  2.500  2.236  0.212  262  16.42  20  358  16.32 •19-8-63 09.25  69°  2.254  2.503  2.236  0.212  358  09.33  21  0  10.45  it  1.276  22  358  11.25  II  2.288  2.646  1.261  0  2.267  354  11.35  Remarks  See F i g . 20c  ) machine ) stopped )  Max moment 3 7 4 kip i n s . ) Torsional )failure mach. ) stopped see ) F i g . 20 a. unloaded re-loaded  TABLE  Set no  Initial Moment : Time Temp o JjT kip ins  V  (continued)  Dial B 5  Dial (fc 6  Dial C 6  Dial O  Final Moment kip ins  Time  23  366  11.39  69°  2.426  2.800  2.387  358  11.47  24  369  11.50  II  2.512  2.900  2.457  358  11.58  25  355  13.46  70°  2.513  2.905  2.456  355  13.56  14.20  71°  1.531  1.683  1.485  26  0  0  14.27  Remarks  ) machine )stopped ) unload beam straightened.  27  0  14.50  II  0  0  0  0  0  14.56  Beam straightened and re-loaded in opposite direction 2 0 t h A p r i l , 1963  TABLE  Set no  Initial Moment Time kip ins  Temp °F  Dial B 6  Dial (£ 6  V  (continued)  Dial C 6  Top Flange Angle  Final Moment kip ins  Time  20-4-63  Remarks See  28  0  09.41  70°  29  44  09.51  "  30  88  31  F i g . 19 6  0"  0"  0"  0.115  0.141  0.123  10.02  0.230  0.273  0.239  132  10.13  e.344  0.404  0.353  32  176  10.22  "  0.461  0.637  0.470  33  220  10.32  "  0.579'  0.671  0.588  34  264  10.42  "  0.698  0.808  0.707  35  308  10.52  "  0.820  0.948  0.829  307.5  11.06  36  352  11.08  "  1.114  1.145  1.125  350 •  11.15  1.421  1.500  1.418  363  11.39  1.663  1.800  1.652  365  11.51  " 1.815  2.000  1.812  366  12.07  8 9 10  4 3 2 12  7  37  363  11.31  38  365  11.45  39  366  11.53  "  "  Ul  TABLE Set no  Initial Moment Time Temp op kip ins  V  (continued)  Dial B  Dial 6  Dial C 6  6  Top Flange Angle  Final Moment kip ins  Time  Remarks  2+0  367  12.09  70°  2.167  2.200  2.172  366  12.17  41  367  12.22  tt  2.400  2.500  2.424  367  12.30  42  368  tt  2.606  2.769  2.638  362  43  357  12.35 22-4-63 09.37  tt  2.614  2.772  2.639  357  12.46 ) machine ) stopped 09.45  44  2.718  2.893  2.740  45  it 387 • • 10.00 23-4-63 72° 369 09.05  2.718  2.895  2.742  46  393  2.788  3.086  2.819  47  371  tt  2.785  3.088  2.822  48  394  tt  2.867  3.185  2.908  49  373  70°  2.864  3.187  2.910  50  397  tt  2.945  3.287  2.999  51  375  75°  2.945  3.291  3.000  09.24 25-4=63 09.10 09.45 27-4-63 10.15 10.35 29-4-63 09.20  11  2°. 6  373 369  2.8  378 371  3.0  375 373  3.2  380 375  10.07 )Max. moment )387 09.17 09.33 )Max moment )393 09.25 10.07 )Max moment )394 10.30 10:44 )Max moment )397 09.36  TABLE  Set no  Initial Moment kip ins  Time  Temp . °F  52  396  53  376  09.41 75° 1-5-63 09.44 72°  54  398  10.00  it  55  0  10.28  73°  Dial B O  3.178  V  (continued)  Dial (fc O  Dial C  3.385  3.076  3.387  3.074  3.482  3.151  6  Top Flange Angle a  3.2  Final Moment kip ins  379  Time  10.07  376  3.4  382  Remarks  )Max  moment  )396 )Max  moment  )398 see F i g . )20b.  0  unloaded  Beam straightened and re-loaded  56  0  14.33  75°  0  0  0  57  88  14.45  76°  0.271  0.306  0.266  58  176  15.03  M  0.787  0.813  0.678  0.4  173  15.10  59  264  15.26  it  1.272  1.526  1.278  1.6  261  15.34  60  352  16.33  it  1.322  1.763  1.346  4.4  348  16.41  61  373  17.40  II  3.382  4.000  3.397  7.9  365  17.57  0 85.6  14.58  5 1  6  4 8 3 9 2  10 L2  7 1 •  Steady at M=373 f o r about 20 min. loading <3  TABLE  Set no  Initial Moment Time kip ins  V  (continued) Final Moment kip ins  Dial B  Dial ch  Dial C  Top Flange Angle  72°  3.382  4.000  3.397  7.9  363  09.22  ii  3.511  4.143  3.523  8.7  378  09.46  1!  3.511  4.142  3.523  8.7  374  09.35  Temp  op  5  6  Time  62  363  2-5-63 09.07  63  388  09.30  64  374  3-5-63 09.20  65  399  09.40  II  3.610  4.251  3.620  8.7  383  10.15  66  0  10.45  II  2.417  2.883  2.454  3.6  0  10.57  67  0  o  Remarks  0  CO  TABLE  V  (continued)  SECTION Set no  Moment kip ins  B  S t r a i n Gauge Reading  1  2  3  4  5  6  7  8  9  - •  -  +  +  +  +  +  +  0  0  0  0  0  0  0  • 157 _ 181  11  +  10 -  -  12 -  0  0  0  0  0  172  95  8  78  132  120  1  0  2  44.5  182  72  5  90  3  88  349  169  2  166  300  350  333  178  10  160  275  337  4  132  506  253  0  250  442  515  490  258  10  240  420  502  5  176  665  336  0  328  585  685  652  342  10  324  565  668  6  222  822  422  2  410  736  858  815  428  12  405  715  832  7  264  973  513  0  492  888  1037  975  512  15  488  875  1020  8  308  0  568  1038  1218  1143  600  16  572  1040  1206  9 10  11  343  1155 ' 605 1545  728  30  752  1252  1282  1385  768  58  655  1120  1516  1610  723  38  754  1232  1253  1386  766  62  650  1117  1528  1690  732  48  786  1260  1285  1432  795  77  668  1138  1585  TABLE S e t Moment • no kip ins.  V  (continued)  S t r a i n Gauge Reading  1  2  3  4  5  6  7  8  9  10  11  12  12  355  2175  787  133  965  1310  1248  1508  962  155  728  1140  1737  13  359  2608.  882  218  1187  1350  1272  1552  1172  245  833  1218  1970  -14  362  3406  1132  238  1376  1408  1265  1590  1360  282 • 969  1326  2680  4640  1200  256  1572  1562  1228  1642  1550  312  1110  1394  3516  15 16  358  4670  1198  253  1575  1555  1215  1635  1555  310  1110  1400  3528  17  •;;3 64  5815  1367  255  1787  1727 . 1200  1682  1795  335  1228  1433  4237  18  366  6908  1520  252  2025  1915  1295  1690  2040  365  1325  1435  4688  19  363  8048  1632  265  2245  2675  1312  1730  2235  390  1394  1438  5060  20  358  8035  1595  267  2245  2655  1303  1713  2235  388  1370  1428  5048  21  0  6523  897  234  1500  1242  - 70  450  1472  347  • '692  268  3552  22  356  8665  1720  208  2272  2450  1332  1838  2300  363  1452  1175  5257  23  ;;3'6;0  9510  1885  175  2415  2516  2615  2040  2507  360  1562  1163  5660  24  360  10002  1975  170  2494  2582  2965  2090  2585  370  1604  1163  5988  TABLE Set no  Moment kip ins.  V  (continued)  S t r a i n L^auge J^ead mg 1  2  3  4  5  6  7  8  2072  2575  25  355  10065  I960  172  2490  2580  2972  26  0  8370  1243  147  1747  1145  1504  -  +  +  +  -  -  -  828 1813  -  9 370  10  11  12  1596  1154  5990  336  905  127 4470  +  +  +  +  27  0  1090  312  73  14  1565  825  325  140  25  122  475  544  28  0  1128  303  78  25  1528  912  309  128  30  119  460  517  29  44  948  376  74 - 63  1686  990  472  220  22  • 190  598  685  30  88  784  468  73  145  1830  1158  635  305  18  275  736  855  880  1022  31  132  617  550  72  227  1978  1327  788  390  15  355  32  176  445  635  70  312  2135  1500  947  478  12  436  1030  1196  33  220  265  725  70  397 2288  1674  1105  568  8  520  1168  1375  34  264  80  813  70  485  2448  1852  1267  658  4  605  1330  1558  35  + 115  906  68  575  2615  2040  1430  754 - 4  693  1487  1757  36  360  1008  68  677  2770  2238  1602  862  785  1636  1984  10  TABLE Set no  Moment kip ins  V  (continued)  S t r a i n Gauge Reading 6 7 5  8  9  10  11  12  2300  1345  78  1063  2111  3196  3604  3184  1617  128  1198  2730  4004  2504  4274  5200  1900  172  1362  3973  4923  1617  2448  4594  6832- 2057  204  1456  4960  5396  58  1760  2400  4942  8418  2228  234  1538  5803  5713  1977  66  1735  2350  5038  8420  2207  235  1527  5788  5688  4028  2030  67. 1785  2396  5120  8863  2264  230  1602  7268  5843  4007  2038  82  1755  2358  5080  8847  2238  210  1620  7398  5835 '  4050  2065^  82  1788  2398  5128  8895  2270  212  1658  7482  5870  4015  2053  85  1772  2368  5094  8868  2252  207  1652  7444  5832  4003  2148  135  1772  2450  5398  8890  2250  152  1753  7992  5904  3975  2143  150  1748  2410  5382  8850  2225  132  1763  8080  5887  1  2  3  4  37  1736  1370  86  1035  2676  3114  38  2605  1580  82  1254  2596  40  3360  1800  75  1498  41  3687  1905  18  42  4017  1998  3978  39  43  357  44  45  369  46  47  371  48 49  373  TABLE Set no  Moment kip in  50 51  375  52 53  376  54  V  (continued)  S t r a i n Gauge Reading  1  2  3  4  5  6  138 1813  3942 2192  139 1798 2395 5528 9997  3976 2198  134  1813 2432  3959 2187  135  1803  166  1800 2413  2230  2420  5520  767 1223  5  143  335 4683  1136  1868 2858  554  748  1803  166  432  597 - 58  176  123 1087  61  367  134  + 28 4225  2595  + 1565 1530  2310  162  86.2  350  6140  353  57  60  155 1857 8972  15  240  1704  2307  4025  625  168 -362  6165  172  168  805  157 1864 8995  552  3110  458  152 1857 8982 6148  4663  0  263  157 1825 9040 6172  7702  56  59  12  106 1163  162 1088  1716 +325  11  6172  2554 1476  174  10  9000  0  18  9  1890  5525  55  215  2307  9977 2318  2447 5545 9956  1152  8  5525 9015 2318  3975 2170  3990  58  7  10090  3990 8578 1557 345  93 1198 2462 3964  44 -340  6020  1550  2725 2235 -100 2440 6870 7230 6485 2688  85  153  5050  - 70 1366 7225  414  3530  135 2198 11220 6265 O  TABLE  Set no  Moment kip ins  1  2  3  V  (continued)  S t r a i n Gauge Reading 6 4 7 5  8  9  10  11  12  62  363  2715  2220  107  2445  6850  7232  6490  2692  150  2182 10953  6275  63  382  2762  2370  180  2850  7345  7984  6232  2970  184  2398 11133  6512  64  375  2748 ,2367  195  2862  7392  8025  6203  2996  198  2400 10937  6502  65  384  2750  2408  235  2976  7837  8344  6054  3106  222  2465 11105  6535  66  0  1005  1603  195  2130  5970  6560  5035  2237  155  1688  9825  4900  67  0  -  -  -  +  -  -  +  +  +  -  +  +  4120  205  35  265  2120  612  1270  313  13  144  5160  145  o  TABLE  V  (continued)  S E C T I O N Cfj_ Set no  Moment kip ins.  S t r a i n Gaug ;e Readin g ;  1 -  -  3  -  4  5  6  7  8  9  10  11  12  0  0  -  +  +  +  +  +  •+  -  0  0  0  0  0  0  0  ' 0  0  85  3  84  160  173  164  87  110  87  -  -  1  0  2  44.5  us.;  3  88  320  166  3  . 168  312  343  322  175  10  118  292  344  4  132  468  248  3  250  462  512  479  262  10  251  440  512  5  176  615  328  4  337  614  682  640  348  12  335  590  677  6  220  750  412  3  422  770  853  800  435 '  13  420  743  848  7  264  862  505  10  505  924  1028  962  522  10  515  893  1026  8  308  954  605  18  584  1075  1206  1112  610  0  615  1038  1210  1052  715  5  735  1356  1312  1330  750  27  715  1172  1455  1047  715  5  783  1345  1298  1320  744  25  714  1170  1472  1093  734  10  761  1380  1326  1358  773  36  722  1187"  1714  9 10 11  343  0  2  +  145  175  TABLE Set no  Moment kip i n s .  1  2  3  V  (continued)  S t r a i n Gauge Reading 6 7 4 5  8  9  10  11  12  885  92  732  1208  2508  12  355  1144  768  50  867  1506  1422  1482  13  358  1198  817  90  1000  1643  1543  1807  1013  138  792  1355  2883  14  360  1314  920  125  1220  1690  1484  2115  1165  180  920  1560  2990  15  363  2610  1142  132  1434  1878  1525  2560  1340  234  1125  1515  3160  16  ;;358  2648  1150  132  1428  1873  1520  2560  1330  238  1128  1500  3160  17  363  3830  1405  150  1655  2068  1625  3262  1565  302  1408  1410  3492  18  364  4787  1665  152  1915  2228  1748  4038  1870  350 . 1706 1325  3950  19  362  5758  1968  156  2294  2414  1845  4935  2387  405  2065  1270  4445  20  358  5677  1975  152  2312  2395  1845  4895  2400  410  2062  1253  4578  21  0  4320  1284  123  1540  968  442  3558  1605  358  1360  81  3100  22  355  6105  2080  110  2325  2235  1925  5112  2450  395  2147  1036  4873  23  359  6662  2346  55  2540  2315  2040  5684  2718  373  2415  980  5688  24  359  7030  2465  58  2708  2420  2138  5940  2937  390  2562  945  6045  TABLE Set no  Moment kip ins.  V-  (continued)  S t r a i n Gauge Reading  1  2  3  4  5  6  7  8  9  10  11  12  25  355  7005  2462  58  2722  2420  2133  5943  2950  395  2550  936  6055  26  0  5525  1745  40  1945  4625  2150  345  1832  + 108  4532  +  +  +  —  —  945  710  —  —  —  —  —  +  —  27  . 0  869  44  67  100  214  210  1345  120  62  95  1345  218  28  0  932  53  69  90  215  213  1366  108  60  96  1340  228  29  44  ^ 770 + 35  68  180  374  380  1212  198  58  182  1488  55  30  88  615  :\118  68  265  532  542  1058  285  55  265  1634  + 112  31  132  464  198  66  347  688  719  905  372  55  348  1782  280  32  176  306  285  65  432  854  890  752  460  52  435  1937  458  33  220  148  372  64  522  1017  1058  595  550  50  524  2090  636  34  262+  + 13  460  65  613  1182  1234  433 • 645  49  612  2247  822  35  178  552  64  706  1343  1413  268  742  48  707  2412  1015  36  364  653  63  808  1495  1593  83  850  44  812  2576  1227 I-  1  o  -3  TABLE Set no  Moment kip i n s .  V  (continued)  S t r a i n Gauge Reading 6 5 7 4  8  9  10  11  12  32  1422  28  1407  5021  2318  3304  270  1953  16  1913  6038  3013  4474  676  2660  5  2758  9415  4196  338  3145 11820 "5335  895  3060  0  3082 10436  4978  2636  393  3440 13378  5920  1030  3272  - 14  3220 10975  5426  1972  2625  388  3417 13330  5863  1047  3243  8  32 02. 10822  5392  2050  2683  405  3510 14058  5980  968  3312  17  3258 11010  5475  2008  2672  398  3482 14040  5955  982  3287  8  3242 10978  5467  2082  2685  417  3512 14063  6047  978  3308  15  3265 11015  5483  2056  2672  406  3493 14030  6017  1000  3286  0  3252 10972  5469  2082  2698  397  3500 14058  6042  985  3293  + 10  3280 10995  5505  2050  2697  382  3473 14018  6008  1006  3270  20  3272 10969  5493  1  2  3  37  1058  1023  125  1344  2395  2190  38  1580  1360  208  1915  4466  40  1812  2040  293  2674  8915  41  2025  2404  42  2062  39  43  357  44 45  369  46 47  371  48 49  373  TABLE Set no  Moment kip ins.  50 51  375  52 53  376  54 55  0  V  (continued)  S t r a i n Gauge Reading  11  12  10  3278 10980  5510  3282  13  3268 10950  5485  1045  3308  5  3282 10972  5517  6138  1052  3295  10  3270 10949  5500  3515 14072  6160  1045  3306  10  3286 10993  5500  2750 12246  4600  2037  2547  13  2540  9725  4000  -  -  +  +  +  +  +  -  5  6  7  8  9  397  3503 14060  6052  987  3298  2692  390  3487 14037  6028  1007  2050  2703  400  3515 14072  6162  2020  2690  404  3503 14042  2078  2712  398  662  1972  397  -  -  -  -  1  2  3  2072  2703  2043  4  10  56  0  5120  408  237  36  5897  204  3415  216  156  110  8572  630  57  86  4590  196  280  238  6345  628  3118  6  152  310  8763  213  58  173.5  3587  +202  257  613  7217  1420  2695  -374  152  693  9085  +580  59  262  2552  392  675  1655  '9260  3122  1930  1590  132  1290  9687  1832  60  349  75  1478  750  2968 12750  5820  2222  2620  40  2370 11380  4175  6l  366  +985  2248  950  4127 16083  8535  3061  3655  - 80  3140 13415  6100  TABLE Set no  Moment kip ins.  1  2  ;  3  V  (continued)  S t r a i n Gauge Reading  4  5  6  7  8  10  .11  12  87 3132 13338 6092  62  363  1010 2285  905 4068 15997 8453 3115  63  380  1070 2335  893 4102 16135 8532 3135 3622  73 3182 13403  64  375  1000 2288  932 4130 16147 8548 3107  3648  64 3178 13358 6148  65  384  1025  2345  915 4150 16235  3664  50  3218 13456  6202  66  0  -604  1535  900 3280 13598 6878 3582 2844  50  2400 12152  4550  67  0  -7264 -860  925  8627 3140  835 6368 1240  3623  3592  9  490  + 26  6163  183 10380 -412  TABLE  V  (continued)  SECTION Set no  Moment kips ins.  1  2  3  4 +  _  C  S t r a i n Gauge Reading 6 7 5  8  9  10  11  12  +  +  +  +  +  —  —  —  —  0  0  0  0  0  0  0  0  0  0  0  0  44.5  182  78  2  90  165  176  160  83  0  86  146  177  3  88  350  152  6  176  320  346  320  168  4  170  292  348  4  132  512  225  8  264  472  513  477  250  4  245  435  512  5  176  674  300  12  352  630  685  638  333  5 . 338  580  678  6  220  848  378  15  442  786  858  800  415  8  428  718  850  7  264  1360  472  8  528  936  1033  964  498  17  532  835  1053  8  308  1780  572  0  617  1088  1207  1115  582  30  640  958  1255  2079  652  45  820  1303  1352  1320  776  + 12  737  1097  1485  2070  648  55  832  1308  1365  1312  787  18  732  1092  1480  2094  660  65  872  1396  1418  1363  830  30  748  1125  1515  1  0  2  9 10 11  343  TABLE Set no  Moment kip i n s .  1  2  . 3  V  (continued)  S t r a i n Gauge Reading 6 5 7 4  8  9  10  11  12  12  354  2107  683  106  1016  1558  1722  1415  935  62  790  1225  1632  13  358  1995  732  137  1213  1913  1752  1792  1092  87  858  1575  1710  14  360  2055  798  170  1432  2666  1893  2138  1264  98  993  2260  1735  15  361  1945  915  220  1653  2956  1995  2312  1438  125  1175  3614  1807  16  358  1930 • 922  226  1657  2957  1995  2292  1437  125  1175  3610  1798  17  362  1844  1064  265  1810  3463  2100  2412  1548  132  1355  418:8  1850  18  363  1758  1176  313  1970  3977  2157  2526  1663  140  1527  4500  1868  19  362  1675  1282  347  2105  4530  2230  2792  1767  145  1675  4680  1894  20  358  1655 ' 1265  355  2108  4520  2225  2748  1765  152  1672  4640  1877  21  0  465  663  285  1310  3110  792  1386  1026  138  957  3230  525  22  355  1705  1267  350  2100  4410  2232  2865  1765  148  1672  4595  1876 .  23  358  1635  1284  370  2147  4492  2255  2980  1800  155  1707  4697  1894  24  358  1558  1340  348  2158  4585  2268  3020  1800  125  1767  4815  1900  TABLE Set no  Moment kip ins.  V  (continued)  S t r a i n Gauge Reading  1  2  3  4  5  6  8  9  10  11  12  3000  1796  125  1768  4814  1890  1648  1070  122  1045  3378  544  —  —  —  +  +  25  355  1545  1340  347  2153  4575  2260  26  0  410  740  280  1368  3177  828  +  +  —  +  —  7  —  —  27  0  277' 110  38  10  350  120  970  158  40  125  828  158  28  0  232  112  46  5  368  108  936  150  46  127  846  153  29  44  102  185  40 - 90  205  285  1102  237  45  212  695  + 20  30  88  + 62  260  32  177  56  455  1265  320  46  298  542  190  31  132  222  333  26  267  - 92  624  1425  407  45  382  392  355  32  176  383  408  22  356  250  794  1588  488  45  468  235  525  33  220  543  485  18  447  407  963  1750  574  45  556  74  695  34  264  705  562  13  540  570  1136  1919  662  45  646  + 91  867  35  867  641  7  635  736  1313 2096  750  46  . 740  268  1037  36  1030  725  0  734  904  1493  845  43  836  448  1203  2323  TABLE Set no  Moment kip ins.  V  (continued)  S t r a i n Gaugei Reading  1  2  3  4  37  1368 1083 - 75 1280  38  1572 134-  5  6  7  8  9  10  11  918 3070 5450 1426 - 53  1275  690  97 1520  889 3887 6468 1710  100 1549  1868  802 4772 8045 2102  140  12 1474  757 1600  39 1708  S-0  1752  41  1878 1996  148 2135  42  1856 2132  165  43 . 357  1842 2117  158 2233  44  2318  2200  152  2313  2190  45  369  46 47  371  48 49  373  122  2253  798 5370  9200 2337  748 5618 9715 2502 720  5572 9640 2487  1952 1235 1850  178 2218 1792 2170 193  2320  1948 2448  188 2318 1933  2398  2545  182 2404  2108 2665  145 2294  732 5672 9672 2537  174 2400  2118 2696  2353 2235  170  778 6342 9715 2622  194 2430  2185 2815  2334 2219  167 2425  2243 2435  122  2468  745 6388 10132 2645  118 2656  2242 2455  100-  2448  732 6372 10143  115 2647 2590 4182  2298  2425  758 5663 9700  76l  6328 9744 2618  2640  189 2408 2269 2818 2595  4192  TABLE  Set Moment no kip ins. 5 0  375  52 53  376  54 55  2  2325 2450  i  51  1  0  3  V  (continued)  Strain- Gauge Reading 4 5 6 7 8  130 2507  690. 6398 11292  9  10  2688  134  2660  11  12  2667 4220  2432  130  2485  674 6385 11415 2672  133  2642 2695 4197  2292 2495  120  2520  702  2684  105  2722 3212  2286 2492  114  2521  688 6428 11393 2678  2312 2506  117 2537  692  6458 11432  2690  97 2732 3248 4314  894 1872  78 1742  610  4925 9978 1950  107 1955 1820 2785  +  +  2324  +  +  +  6443 11422  -  99 2713  +  -  —  -  +  163  3292  356  + 37 2900  727  0  575  80  180  448 1600  180 2330  163  15  57  85.5  892  250  165  232 1287  592 2762 - 35  20  132 -140  173  1192  542  59  261  1466  995  60  348  1776 1835 = 65  61  366  2275 2648  70  740  897 1355 3700  396  25  387 2010 1280  383 2570 5253  962  40  943  1825 -188 4737 8384 1988  300 3025  3232 4204  -  56  58  4212  632 6995 11558 3180  513  2056  85 1956 +2545 3329 260  2930 6877 5210  TABLE Set no  Moment kip ins.  ^ 1  2  3  V  (continued)  S t r a i n Gauge Reading 6 5 4 7  8  9  10  11  12  62  363  2272  2645  300  3018  622  6982  11,532 3 1 7 7  258  2930  6865  63  379  2738  2773  290  3125  823  7168  11508  3273  253  3063  6972 . 5 7 0 9  62+  375  272+0  2776  278  3114  818  7152  11484  3263  247  3070  6955  5733  65  382+  2814  2824  294  3210  1066  7544  11408  3328  255  3121  7012  5918  2110  205  2302  +314  5838  9988  2468  210  2300  5385  4252  + 144  +408  1503  2105  + 78  80  -188  6430  66  0  1306  67  0  810  98  205  5197  105  117 Conclusions The  following conclusions a r e drawn f r o m  these  tests:  i - N o s i g n i f i c a n t d i f f e r e n c e in bending s t r e n g t h i s e v i d e n t b e t w e e n t h e initial bending t e s t made on p r e - c o m p r e s s e d m e m b e r A 5 and t h e i n i t i a l bending t e s t on m e m b e r A 4 . T h i s may, h o w e v e r , be a t t r i b u t e d t o t h e f a c t t h a t member A 5 was n o t p r e - c o m p r e s s e d e n t i r e l y into t h e plastic range. ii - N o s i g n i f i c a n t d i f f e r e n c e in bending s t r e n g t h is e v i d e n t b e t w e e n t h e initial o r v i r g i n bending t e s t s and t h e s u b s e q u e n t bending t e s t s made on t h e re-straightened members. iii -  A s i g n i f i c a n t r e g a i n in s t r e n g t h o c c u r s a period o f r e s t a t c o n s t a n t s t r a i n .  following  iv - T h e s t r a i n p a t t e r n s in t h e p l a s t i c r a n g e , a s m e a s u r e d by e l e c t r i c s t r a i n g a u g e s , d i f f e r s considerably f r o m t h e theoretical s t r a i n d i s t r i bution . v - T h e m o d e s o f f a i l u r e in bending t e s t bending t e s t n u m b e r 2 w e r e entirely, T h i s d i f f e r e n c e may be a c c i d e n t a l .  number 1 and different.  t  BIBLIOGRAPHY  119 BIBLIOGRAPHY  A . S .C .E . Commentary on P l a s t i c Design S t e e l ; A . S . C . E . Manuals o f Engineering P r a c t i c e , No. 2+1, 1961 Beedle, L . and T a l l , L . " B a s i c Column S t r e n g t h " , J o u r n a l of the S t r u c t u r a l Division, V o l . 8 6 , No. S T 7 , ( J u l y I 9 6 0 ) , pp. 139-173. Thurlimann, B r u n o . "New A s p e c t s Concerning Inelastic Instability o f S t e e l S t r u c t u r e s " , J o u r n a l o f the S t r u c t u r a l Division, V o l . 8 6 , No. S T l ( J a n u a r y I 9 6 0 ) , pp. 99-120  REFERENCES  121 REFERENCES  1  Beedle and'Tall, "Basic Column S t r e n g t h " , J o u r n a l of the S t r u c t u r a l Division, A . S . C . E . , V o l . 86, No. S T 7 ( J u l y I960), p. 152.  2  O g . C i t . , pp.  3  A . S . C . E . Commentary on P l a s t i c Design in S t e e l , A . S . C . E . Manuals of Engineering P r a c t i c e No. 41, 1961, p. 21.'  4  A . S . C . E . Op. C i t . , p. 86.  5  Beedle and T a l l , op_. c i t . , pp.  6  B . Thurlimann, "New A s p e c t s Concerning Inelastic Instability o f S t e e l S t r u c t u r e s " . J o u r n a l o f S t r u c t u r a l Division, A . S . C . E . V o l . 86 No. S T 1 ( J a n u a r y i960) , p. 110.  7  151-152.  , L o c . C i t . , p.  110.  8  A . S . C . E . Op. C i t . , p. 150.  9  A . S . C . E . Op. C i t . , p. 60.  10  A . S . C . E . Op_. C i t . , p. 50.  141-145.  FIGURES  1  ii - \of-z"  •Br  R6  3  Locat\ov» o\ t e s t 'sp«-CLmens of 5 "* 5" * 1G lk- \AF • b e a - m .  •5-0.  Jl'-J.^z.''  RS  38-2 60-2  cut  from  40-2  AO-7  37-8  sina^e  \er\<^-VV\  SO-5 40-5  64-5 -  4-3-a 42-2 ST, * =  3"  u  »•  4,7-8 Gl - 3  44- 6 42- O C3TI -  —  J 40-2  U ^ p e r and ^ i e r ic^uare  40-0 38-9  38-e  44-3  S3-7  6 9 - 2  looj'er y i e l d . av\d u l t v m a V e s t r e s s , r n VncVv 0 b t a i r\e.d- f r o m i o u ^ o a te.&ts».  © Figure. 1  Wibs.  l-2o -  I-IO .  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