International Construction Specialty Conference of the Canadian Society for Civil Engineering (ICSC) (5th : 2015)

An integrated process-based simulation platform for construction project planning Ismail, Ali; Scherer, Raimar Jun 30, 2015

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5th International/11th Construction Specialty Conference 5e International/11e Conférence spécialisée sur la construction    Vancouver, British Columbia June 8 to June 10, 2015 / 8 juin au 10 juin 2015   AN INTEGRATED PROCESS-BASED SIMULATION PLATFORM FOR CONSTRUCTION PROJECT PLANNING Ali Ismail1,2 and Raimar Scherer1,3 1 TU Dresden, Germany 2 ali.ismail@tu-dresden.de 3 raimar.scherer@tu-dresden.de Abstract: The application of simulation technique for construction project planning is a very promising but also a challenging field of research. Creating reliable and reusable simulation models is very complex, combined with high costs. This paper presents the development of Construction Simulation Toolkit “CST” and a collaborative simulation portal “ProSIM”, which supports the planning of construction project using discrete-event simulation method. The objective of this research is promoting a wider adoption of simulation in construction industry and support planning of real project using simulation technique through providing a construction-specific simulation toolkit allowing the rapid development of simulation models and an online collaborative platform in order to facilitate the integration of complex construction projects data. CST aims to support planning of production and logistic operations of construction projects in one unified simulation models and running “what if” scenarios in order to support decision making and improve planning quality, while ProSIM aims at enabling the collaboration among the simulation experts and other project design and planning teams.The paper presents the latest research work and the prototype implementation through study cases. 1 INTRODUCTION Construction planning is a fundamental and challenging activity in the management and execution of construction projects. It involves the choice of technology, the definition of work tasks, the estimation of the required resources and durations for individual tasks, and the identification of any interactions among the different work tasks (Chris 2000). There are many planning methods and techniques to help with project and resource planning; one of the advanced techniques is using simulation technique. It can help to optimize project schedules and run “what if” scenarios or test different construction strategies or different resource profiles to proof and compare different plans against different goals e.g. total duration of the project, total cost, and resource utilization aspects. However using simulation for construction projects is still limited compared to other branches of industries. Adoption by construction industry has lagged, for three potential reasons: (1) simulation is not accessible, (2) it cannot handle the complexity of modern construction projects, and (3) the benefits are not immediately obvious (AbouRizk 2011). Therefore, providing a convenient simulation tools and collaborative platforms to support and integrate the huge and complex projects data with low-cost entry for construction industry is crucial to promote a wider adoption of simulation in construction industry. With convenient we mean here tools which are designed especially to take in account the unique aspects and commonly used data models in construction industry. Consequently, having such tools will improve the planning quality and reduce costs, waste and construction conflicts. 331-1 The Construction Simulation Toolkit CST and the web-based collaborative portal for managing simulation models “ProSIM” have been developed within the national German leading research project Mefisto (www.mefisot-bau.de 2009-2012) which is a part of the IKT 2020 research for innovation intuitive. The development of CST aims to accelerate the process of creating reliable simulation models for production and logistic operations during the planning and operation phases of construction projects. ProSIM portal aims to enable communication and collaboration between involved planning and simulation experts. In general, simulation models based on CST aim to support the planning process in order to reduce the total duration and cost of construction projects and to avoid any conflicts during the construction phase by improving the planning quality and utilization rates of resources. The simulation model should support the project manager to verify the feasibility of a given project schedule with a combination of different resource constraints or different building design alternatives or construction methods. The toolkit provides a set of reusable simulation components with a simple user interface for rapid building of process-based simulation models for planning projects with resource and activity calendar constraints. It has a modular structure and consists of a set of simulation reusable input and output components.  Sections 2 and 3 describe briefly the concept of using formal reference process models of construction operations and the multi-model data exchange approach. Section 4 presents the simulation platform architecture and provides more details about CST and ProSIM implementation, finally in section 5 a two study cases are discussed. 2 REFERENCE PROCESS MODELLING OF CONSTRUCTION OPERATIONS Reference models are generic conceptual models that formalise recommended practices for a certain domain (Rosemann 2002). As the knowledge in every domain keeps evolving, the reference models change continuously and goes through a "discover, model, evaluate, and optimize" modelling cycle. So new reference models will be added or existing models will be improved and detailed with time. Therefore, a continuous collaboration between planning, construction management and simulation teams is very important to capture the best practice of delivering construction and logistic activities as well as to validate and integrate the feedbacks during the construction phase of real projects. The reference process modelling method allows identifying, capturing, documenting, improving and sharing the knowledge about the best practice of construction processes and their related information. In our approach, there is a clear separation between the core simulation components and the process models for the application domains. Business Process Modelling and Notation (BPMN) models are used to capture and describe the logic of production and logistic operations and to transform them automatically in one step into simulation models. Special BPMN Extension elements are developed in order to define resource requirements and durations of tasks inside the reference models in a flexible way. Each activity or task inside the project schedule is linked with a reference process model during simulation.  In this way, the process models define the logic and level of details of simulation models. One needs to examine every detail of the construction process carefully and identify the major events and processes that will be presented in the simulation model in order to create a reliable simulation model (Aouad et al. 2006). The graphical representation of BPMN models makes models easy to understand between all involved teams and the formal specifications in XML allows transforming process models into simulation models automatically. The BPMN reference process models will be transformed and imported into a ready to use process templates repository in the simulation toolkit. The process repository includes reference process models which are reusable across different construction projects and their data definitions of resources and productivity factors. In our approach, aforementioned BPMN modelling technique is used to create semantic and graphic process models for various construction operations. BPMN models consist of simple diagrams constructed from a limited set of graphical elements.  Flow Objects are the main elements to define and control the behaviour of a business process. The scope of BPMN elements which can be used inside the simulation process templates are: 331-2 • Start/End events • Task and sub-process • Sequence flow • Gateways: Parallel Fork/Join , Data-Based XOR • Conditional and default flow. Process models will be imported into a process catalogue as ‘ready to use’ Reference Process Models (RPM) inside the simulation model. The process catalogue includes reference process models for the best practices of various construction processes that are reusable across different construction projects. In addition, RPMs are extended to include resource requirements and productivity factors. The knowledge accumulation enables a continuous improvement of the process catalogue. A process template can be as simple as having one single activity or a set of serial activities which run sequentially without any kind of control flow or very complex ones including loops and conditional gateways which may result in skipping/ repeating some activities. In order to create reliable simulation model, one needs to carefully examine every detail of the construction process and identify the major events and processes that will be presented in the simulation model (Akhavian and Behzadan 2011). In CST, the user has the freedom to move the logic and the dependencies between different tasks to be a part of the input data for each simulation model or to be included inside process templates. However this may lead to one of the following extreme situations: 1. Very detailed project schedule and a lot of tasks dependencies as a part of simulation input with a set of simple process templates for each task. 2. Very simple project schedule consisting of few tasks with a high level of abstraction combined with very complex process templates. Both cases must be avoided to get the most out of the simulation model in the sense of ease of use and the flexibility of answering as many as “what if” scenarios. It is mainly the responsibility of the user to maintain balance between these options according to the simulation goal and the availability of data. Figure 1 shows as an example of a good balanced process template for erecting a wall for three construction methods: Precast, In-situ concrete and as bricks walls.  By using this template there is no need to use three different templates and link them explicitly to each wall as part of the simulation input, which reduce the time and efforts to prepare the simulation data. The definition of resources and duration value/formula for each single task can be embedded inside the BPMN process template or maintained in separate database. 331-3  Figure 1: BPMN process model template for wall erecting  3 MULTI-MODEL PROJECT DATA EXCHANGE APPROACH Multi-model project planning is a paradigm shift from the building-centric approach, which tries to add and link all project data with building models toward an equivalent interlinked data models using special link models. The multi-model method offers solutions to structural problems of nD modelling in construction information processes (Akhavian and Behzadan 2011). A multi-model container comprises several data files and includes, besides the meta-information about the container content, several application models as well as link models (Schapke and Scherer 2010). It allows the combination of heterogeneous application models from different domains and various data formats. Inside multi-model containers link models bind the application models together (Fig. 2).  The link models specify the relationships between items from different data models. Multi-model containers can be used to exchange associated models among the project stakeholders by a common format (Fuchs et al. 2010). In their entirety the multi-models on a construction project open up a multi-dimensional information space of interdependent application models that can be independently processed by the project participants. Each participant has the opportunity to produce new application models on his/her own responsibility and interlink them with existing models. Depending on the situation these newly created multi-models can be maintained locally or published project-wide as a basis for further planning and controlling tasks. In comparison to the often pursued integration of project information in central project databases or product model servers, this approach distributed model-based collaboration represents a paradigm shift (Schapke and Pflug 2012). Multi-model approach is integrated with CST through providing import/export interfaces. 331-4 • Multi-Model-Container: It is the import/export interface between a multi-model container and the internal data in simulation model • BIM Data: This component contains all the information from the BIM model that is relevant for the simulation and extracted from IFC models using special scripts based on the IFCWebServer.org data model server, or created inside the simulation model directly using the Floor-Editor component. • Task List: This component is an important core element for simulation input. It contains all the information about the logistic and construction operations that they have to be simulated • Resource-Pool: This component is a manager and container for all available resources and the definition of their capacities during the simulation.  It includes standard resources used in construction domain like labours, equipment, and building materials or any kind of resources, which can be added in a generic way. The availability of resources is defined as delivery tables (time, amount, attributes) so level of resources can vary over time in a planned manner. • Construction Site: With the help of this simulation component the information of the construction site layout and equipment i.e. transportation routes, tower cranes, storage space, loading zone, arrivals and departures are managed. The changes to the construction site layout during the project progress are considered • Process Repository: This component manages the global Reference Process Models RPMs  of typical construction process. • Process-Pool: Process Pools are virtual hierarchical containers of process instances; each process pool can contain other process pool objects or process instances. In this way it is possible to put a set of related tasks inside one process pool object and define the “end to start” relationships between different groups of tasks using an alphabetic hierarchical string in a very flexible and powerful way. The status of any process pool object will change from “started” to “completed” when all process instances and sub-process pools inside it are complete. The hierarchy structure of the process pool is not restricted in any way, however it is recommended to use a similar hierarchy structure of the real project and to create sub process-pools for each summary task in the project schedule, for example: • Construction site: With the help of this component the information about construction site layout and equipment are managed. At moment CST supports the following elements: • Gantt Charts: It represents the simulation results (planning schedules) as Gantt charts. It allows combining the individual sub-tasks to summary tasks, compare different simulation scenarios and export the results in various level of details to MS Project. • Draw-Panel: With help of this component 2D graphical representation and animations of the progress of construction processes can be created during the simulation. Each task inside the process model can be provided with a special code to draw on a different layer with predefined colours regarding the kind and location of the construction activities. • Project Monitor: This component displays the resource utilization and material consumption graphically during the simulation run, for example, the utilization rates of workers, tower cranes, concrete pumps and material consumption. • 4D Visualizer: This component provides the ability to visualize and animate (3D&4D) the construction progress and state of construction site elements at any time point. 3D models are exported using the standard format COLLADA and the export function can be configured to run based on fixed time intervals, (hourly, daily, weekly, etc.) or after the finish of certain construction processes. 4D visualization can be generated automatically using the 3D models and special scripts written for Trimble SketchUP ®. • Floor-Editor: With the help of this component the user can quickly create a simplified building model. • Project Template: The input and output simulation components are combined together as the default simulation project template. This makes it possible to create simulation models very quickly and to simulate and compare different scenarios of the same construction project in parallel. 4.2 Collaborative Portal ProSIM The ProSIM platform is designed as an online web-based portal to support the communication and collaboration among all project planning members and to publish simulation model results and all related input data (Ismail et al., 2014). It facilitates the verification of all input parameters and simulation results effectively 331-7 Besides publishing simulation models, their scenarios and results, it offers the following functions: • Online management of productivity factors of various construction operations  (http://bci52.cib.bau.tu-dresden.de:3000/aws) • Online management of resource requirements and task duration definitions  (http://bci52.cib.bau.tu-dresden.de:3000/aws) • Online repository of reference process models of construction activities as BPMN models (http://bci52.cib.bau.tu-dresden.de:3000/rpms) • Multi-Model Navigator to explore and transform the content of interlinked project data (http://bci52.cib.bau.tu-dresden.de:3000/mmc) • Online viewers of various input and output data (Gantt charts, resource utilization charts, 2D animations, Calendar view, etc.) ProSIM is implemented using the modern web development framework “Ruby on Rails”. This web development framework was chosen because it is suitable for rapid development. It also emphasizes the use of well-known software engineering patterns and principles, such as active record pattern, and Model–View–Controller MVC. The Web application is deployed via Apache web server and MySQL database. 5 STUDY CASIES: 5.1 Mefisto Office Project The first demonstration and validation simulation project “Mefisto office” is a multi-storey office building. The structural work activities have been simulated based on a rough master project schedule. In this project all simulation input data was created or imported manually and the logistic (construction site layout, material delivery, etc.) and cost information were excluded. For this project 2 simulation models and various scenarios were implemented and analysed in order to: (1) Automatic generation of detailed project schedules for the whole building taking in account different construction strategies and maximal resource capacities, (2)  Simulate and optimize the structural work for short term planning  of construction phase taking in account the formwork and reinforcement work details. More details and simulation scenarios are this demonstration project are described in (Ismail and Scherer 2014).  Figure 6: The effect of changing number of workers on the of structural work duration  331-8 Fig. 6 shows the effect of changing the number of workers between 10-40 workers on the expected duration of structural work, workers utilization and the consumption of concrete for 2 floors.  All results of simulation scenarios for this project are available under: http://bci52.cib.bau.tu-dresden.de:3001/simweb/ 5.2 Mefisto Airport Terminal Project For the second demonstration project “Mefisto Airport” two simulation models based on CST toolkit were implemented and different scenarios were prepared and carried out.  The first test case was to generate automatically a detailed project schedule of construction work of the whole building based on the concept of “top-down simulation method” described in details in (Ismail 2011). The main inputs of this case are: (1) master project schedule, (2) high level reference process model which describe the logic of structure work in each floor, and (3) a set of detailed reference process models which describe the logic of structural work for different kind of building elements (slab, beam, column, etc.).  The multi-model project delivery approach and multi-model-container data exchange method have been used in order to extract all related project information and transform them to the internal data structure of the simulation model as following: • The master schedule in the multi-model container (in iTOW XML format) has been transformed into a “Task list” simulation component. Each task represents the structural works within one floor or a work-section has been linked with the high level reference process model of structural work. • The simulation related data inside the IFC model of the building were processed using MMQL, BIMFit and IFCWebServer data model server and converted to the internal data structure of the simulation database. • Link model data has been imported into simulation model in one step After the automatic generation of the detailed project schedule a “minimal project duration” scenario was carried out. In this scenario the capacity of available workers and building material was set to unlimited and only the capacity of tower cranes were considered. The aim of this scenario was to validate and test the feasibility of top-down simulation method and also to analysis the effect of changing the construction strategies and the dates of milestones in the master schedule on the ultimate minimum construction duration. The simulation model and the results of this test case are available through ProSIM under: http://bci52.cib.bau.tu-dresden.de:3000/sim_models/3 The second case study for the Mefisto Airport focused on the simulation of structural work inside one floor. The target was to analyze the effect of changing various factors like resource capacities, the interaction between production and logistic operations and construction methods (in situ concrete, precast) on the expected total duration and the resources utilization ratio. In order to simulate the logistic operations the necessary information about the construction site model was imported from a special IFC model. This model includes the following information: entry and exits gates, transport ways, tower cranes properties and location and yard storage areas. This information was mapped directly into the internal data structure of the “Construction Site” component, which convert them in turn into active and passive material flow simulation objects. With help of “4D Visualizer” component the construction site model can be generated automatically as 4D models including full movement records of crane operations and yard storage areas utilization rates. The simulation model and the results of both scenarios are available through ProSIM under: http://bci52.cib.bau.tu-dresden.de:3000/sim_models/8 6  CONCLUSION AND FUTURE WORK The target of this research was to promote a wide adoption of simulation methods to support construction project planning. Systems integration and collaboration are believed to be the key enabling technologies that drive the construction industry in improving productivity and efficiency (Shen et al., 2010). This paper 331-9 presented the design and development efforts of a process-based simulation toolkit and a collaborative platform and discussed the integration of various project data models into the simulation models using multi-models data exchange approach. It discussed also the concept of using formal process models based on BPMN in order to capture and manage knowledge in construction domain and transfer them directly into simulation models. The results obtained from demonstration projects showed the potential of using CST and ProSIM by the rapid deployment of simulation models and the flexibility of applying various scenarios. The future development will include the integration between the simulation platform and the project real data collected on site and adding more reference process models for other project types or disciplines like bridges and electric and interior work. Acknowledgements The research in this paper was enabled by the financial support of the German Federal Ministry of Education and Research (BMBF), Department of ICT under contract n° 01IA09001A, which is herewith gratefully acknowledged References AbouRizk S. 2011. A Construction Synthetic Environment Integrating Visualization and Simulation. ConVR 2011:11th International Conference on Construction Applications of Virtual Reality- pp 10-22 Aouad, G, Lee, A and Wu, S. 2006. nD modelling for collaborative working in construction. Architectural Engineering and Design Management, (1), pp. 33-44.  Akhavian,R. Behzadan, H. A. 2011. Dynamic Simulation of Construction Activities Using Real Time Field Data Collection. European Group for Intelligent Computing in Engineering Workshop Chris Hendrickson. 2000. Project Management for Construction, Carnegie Mellon University. Ismail A., Srewil Y., Scherer R.J. (2014) ‘Collaborative Web-based Simulation Platform for Construction Project Planning’, in PRO-VE 2014: Proceeding of the 15th IFIP working Conference on Virtual Enterprises, Netherlands, Amsterdam. Ismail A., Scherer R.J.2014: Integration of Simulation Data for Construction Project Planning Using a Process-based Simulation Framework, In: Proc. of the 13th International Conference on Modelling and Applied Simulation (MAS), France, Bordeaux.  Ismail, A. and Scherer, R.J. (2014) ,”Simulation of construction variations using a process-based simulation toolkit” in Scherer and Schapke(Eds.)  Information Systems in Civil Engineering – Applications, Springer , DOI 10.1007/978-3-662-44760-4_6 , ISBN 978-3-662-44759-8, Germany, pp.693–725 Fuchs S., Katranuschkov P. and Scherer R.J. 2010. A framework for multi-model collaboration and visualization. Proceedings of “eWork and eBusiness in Architecture, Engineering and Construction” conference, 14-16 Sept. 2010, Cork, Ireland. Rosemann. M. 2002. Application reference models and building blocks for management and control (ERP Systems). In, P. Bernus, L. Nemes, & G. Schmidt (Eds.) Handbook of enterprise architecture (pp. 595-615). Berlin: Springer. Schapke, S.-E.  and Scherer, R. J. 2010. A distributed multi-model based Management Information System for simulation and decision making on construction projects. Advanced Engineering Informatics Journal, Special Issues of the ICCCBE & EG-ICE10 Conference, Elsevier  Schapke S.-E. and Pflug, C.2012. Multi-models: New potentials for the combined use of planning and controlling information.  Transparent - das Magazin, vol. 37, June 2012   331-10  5th International/11th Construction Specialty Conference 5e International/11e Conférence spécialisée sur la construction    Vancouver, British Columbia June 8 to June 10, 2015 / 8 juin au 10 juin 2015   AN INTEGRATED PROCESS-BASED SIMULATION PLATFORM FOR CONSTRUCTION PROJECT PLANNING Ali Ismail1,2 and Raimar Scherer1,3 1 TU Dresden, Germany 2 ali.ismail@tu-dresden.de 3 raimar.scherer@tu-dresden.de Abstract: The application of simulation technique for construction project planning is a very promising but also a challenging field of research. Creating reliable and reusable simulation models is very complex, combined with high costs. This paper presents the development of Construction Simulation Toolkit “CST” and a collaborative simulation portal “ProSIM”, which supports the planning of construction project using discrete-event simulation method. The objective of this research is promoting a wider adoption of simulation in construction industry and support planning of real project using simulation technique through providing a construction-specific simulation toolkit allowing the rapid development of simulation models and an online collaborative platform in order to facilitate the integration of complex construction projects data. CST aims to support planning of production and logistic operations of construction projects in one unified simulation models and running “what if” scenarios in order to support decision making and improve planning quality, while ProSIM aims at enabling the collaboration among the simulation experts and other project design and planning teams.The paper presents the latest research work and the prototype implementation through study cases. 1 INTRODUCTION Construction planning is a fundamental and challenging activity in the management and execution of construction projects. It involves the choice of technology, the definition of work tasks, the estimation of the required resources and durations for individual tasks, and the identification of any interactions among the different work tasks (Chris 2000). There are many planning methods and techniques to help with project and resource planning; one of the advanced techniques is using simulation technique. It can help to optimize project schedules and run “what if” scenarios or test different construction strategies or different resource profiles to proof and compare different plans against different goals e.g. total duration of the project, total cost, and resource utilization aspects. However using simulation for construction projects is still limited compared to other branches of industries. Adoption by construction industry has lagged, for three potential reasons: (1) simulation is not accessible, (2) it cannot handle the complexity of modern construction projects, and (3) the benefits are not immediately obvious (AbouRizk 2011). Therefore, providing a convenient simulation tools and collaborative platforms to support and integrate the huge and complex projects data with low-cost entry for construction industry is crucial to promote a wider adoption of simulation in construction industry. With convenient we mean here tools which are designed especially to take in account the unique aspects and commonly used data models in construction industry. Consequently, having such tools will improve the planning quality and reduce costs, waste and construction conflicts. 331-1 The Construction Simulation Toolkit CST and the web-based collaborative portal for managing simulation models “ProSIM” have been developed within the national German leading research project Mefisto (www.mefisot-bau.de 2009-2012) which is a part of the IKT 2020 research for innovation intuitive. The development of CST aims to accelerate the process of creating reliable simulation models for production and logistic operations during the planning and operation phases of construction projects. ProSIM portal aims to enable communication and collaboration between involved planning and simulation experts. In general, simulation models based on CST aim to support the planning process in order to reduce the total duration and cost of construction projects and to avoid any conflicts during the construction phase by improving the planning quality and utilization rates of resources. The simulation model should support the project manager to verify the feasibility of a given project schedule with a combination of different resource constraints or different building design alternatives or construction methods. The toolkit provides a set of reusable simulation components with a simple user interface for rapid building of process-based simulation models for planning projects with resource and activity calendar constraints. It has a modular structure and consists of a set of simulation reusable input and output components.  Sections 2 and 3 describe briefly the concept of using formal reference process models of construction operations and the multi-model data exchange approach. Section 4 presents the simulation platform architecture and provides more details about CST and ProSIM implementation, finally in section 5 a two study cases are discussed. 2 REFERENCE PROCESS MODELLING OF CONSTRUCTION OPERATIONS Reference models are generic conceptual models that formalise recommended practices for a certain domain (Rosemann 2002). As the knowledge in every domain keeps evolving, the reference models change continuously and goes through a "discover, model, evaluate, and optimize" modelling cycle. So new reference models will be added or existing models will be improved and detailed with time. Therefore, a continuous collaboration between planning, construction management and simulation teams is very important to capture the best practice of delivering construction and logistic activities as well as to validate and integrate the feedbacks during the construction phase of real projects. The reference process modelling method allows identifying, capturing, documenting, improving and sharing the knowledge about the best practice of construction processes and their related information. In our approach, there is a clear separation between the core simulation components and the process models for the application domains. Business Process Modelling and Notation (BPMN) models are used to capture and describe the logic of production and logistic operations and to transform them automatically in one step into simulation models. Special BPMN Extension elements are developed in order to define resource requirements and durations of tasks inside the reference models in a flexible way. Each activity or task inside the project schedule is linked with a reference process model during simulation.  In this way, the process models define the logic and level of details of simulation models. One needs to examine every detail of the construction process carefully and identify the major events and processes that will be presented in the simulation model in order to create a reliable simulation model (Aouad et al. 2006). The graphical representation of BPMN models makes models easy to understand between all involved teams and the formal specifications in XML allows transforming process models into simulation models automatically. The BPMN reference process models will be transformed and imported into a ready to use process templates repository in the simulation toolkit. The process repository includes reference process models which are reusable across different construction projects and their data definitions of resources and productivity factors. In our approach, aforementioned BPMN modelling technique is used to create semantic and graphic process models for various construction operations. BPMN models consist of simple diagrams constructed from a limited set of graphical elements.  Flow Objects are the main elements to define and control the behaviour of a business process. The scope of BPMN elements which can be used inside the simulation process templates are: 331-2 • Start/End events • Task and sub-process • Sequence flow • Gateways: Parallel Fork/Join , Data-Based XOR • Conditional and default flow. Process models will be imported into a process catalogue as ‘ready to use’ Reference Process Models (RPM) inside the simulation model. The process catalogue includes reference process models for the best practices of various construction processes that are reusable across different construction projects. In addition, RPMs are extended to include resource requirements and productivity factors. The knowledge accumulation enables a continuous improvement of the process catalogue. A process template can be as simple as having one single activity or a set of serial activities which run sequentially without any kind of control flow or very complex ones including loops and conditional gateways which may result in skipping/ repeating some activities. In order to create reliable simulation model, one needs to carefully examine every detail of the construction process and identify the major events and processes that will be presented in the simulation model (Akhavian and Behzadan 2011). In CST, the user has the freedom to move the logic and the dependencies between different tasks to be a part of the input data for each simulation model or to be included inside process templates. However this may lead to one of the following extreme situations: 1. Very detailed project schedule and a lot of tasks dependencies as a part of simulation input with a set of simple process templates for each task. 2. Very simple project schedule consisting of few tasks with a high level of abstraction combined with very complex process templates. Both cases must be avoided to get the most out of the simulation model in the sense of ease of use and the flexibility of answering as many as “what if” scenarios. It is mainly the responsibility of the user to maintain balance between these options according to the simulation goal and the availability of data. Figure 1 shows as an example of a good balanced process template for erecting a wall for three construction methods: Precast, In-situ concrete and as bricks walls.  By using this template there is no need to use three different templates and link them explicitly to each wall as part of the simulation input, which reduce the time and efforts to prepare the simulation data. The definition of resources and duration value/formula for each single task can be embedded inside the BPMN process template or maintained in separate database. 331-3  Figure 1: BPMN process model template for wall erecting  3 MULTI-MODEL PROJECT DATA EXCHANGE APPROACH Multi-model project planning is a paradigm shift from the building-centric approach, which tries to add and link all project data with building models toward an equivalent interlinked data models using special link models. The multi-model method offers solutions to structural problems of nD modelling in construction information processes (Akhavian and Behzadan 2011). A multi-model container comprises several data files and includes, besides the meta-information about the container content, several application models as well as link models (Schapke and Scherer 2010). It allows the combination of heterogeneous application models from different domains and various data formats. Inside multi-model containers link models bind the application models together (Fig. 2).  The link models specify the relationships between items from different data models. Multi-model containers can be used to exchange associated models among the project stakeholders by a common format (Fuchs et al. 2010). In their entirety the multi-models on a construction project open up a multi-dimensional information space of interdependent application models that can be independently processed by the project participants. Each participant has the opportunity to produce new application models on his/her own responsibility and interlink them with existing models. Depending on the situation these newly created multi-models can be maintained locally or published project-wide as a basis for further planning and controlling tasks. In comparison to the often pursued integration of project information in central project databases or product model servers, this approach distributed model-based collaboration represents a paradigm shift (Schapke and Pflug 2012). Multi-model approach is integrated with CST through providing import/export interfaces. 331-4 • Multi-Model-Container: It is the import/export interface between a multi-model container and the internal data in simulation model • BIM Data: This component contains all the information from the BIM model that is relevant for the simulation and extracted from IFC models using special scripts based on the IFCWebServer.org data model server, or created inside the simulation model directly using the Floor-Editor component. • Task List: This component is an important core element for simulation input. It contains all the information about the logistic and construction operations that they have to be simulated • Resource-Pool: This component is a manager and container for all available resources and the definition of their capacities during the simulation.  It includes standard resources used in construction domain like labours, equipment, and building materials or any kind of resources, which can be added in a generic way. The availability of resources is defined as delivery tables (time, amount, attributes) so level of resources can vary over time in a planned manner. • Construction Site: With the help of this simulation component the information of the construction site layout and equipment i.e. transportation routes, tower cranes, storage space, loading zone, arrivals and departures are managed. The changes to the construction site layout during the project progress are considered • Process Repository: This component manages the global Reference Process Models RPMs  of typical construction process. • Process-Pool: Process Pools are virtual hierarchical containers of process instances; each process pool can contain other process pool objects or process instances. In this way it is possible to put a set of related tasks inside one process pool object and define the “end to start” relationships between different groups of tasks using an alphabetic hierarchical string in a very flexible and powerful way. The status of any process pool object will change from “started” to “completed” when all process instances and sub-process pools inside it are complete. The hierarchy structure of the process pool is not restricted in any way, however it is recommended to use a similar hierarchy structure of the real project and to create sub process-pools for each summary task in the project schedule, for example: • Construction site: With the help of this component the information about construction site layout and equipment are managed. At moment CST supports the following elements: • Gantt Charts: It represents the simulation results (planning schedules) as Gantt charts. It allows combining the individual sub-tasks to summary tasks, compare different simulation scenarios and export the results in various level of details to MS Project. • Draw-Panel: With help of this component 2D graphical representation and animations of the progress of construction processes can be created during the simulation. Each task inside the process model can be provided with a special code to draw on a different layer with predefined colours regarding the kind and location of the construction activities. • Project Monitor: This component displays the resource utilization and material consumption graphically during the simulation run, for example, the utilization rates of workers, tower cranes, concrete pumps and material consumption. • 4D Visualizer: This component provides the ability to visualize and animate (3D&4D) the construction progress and state of construction site elements at any time point. 3D models are exported using the standard format COLLADA and the export function can be configured to run based on fixed time intervals, (hourly, daily, weekly, etc.) or after the finish of certain construction processes. 4D visualization can be generated automatically using the 3D models and special scripts written for Trimble SketchUP ®. • Floor-Editor: With the help of this component the user can quickly create a simplified building model. • Project Template: The input and output simulation components are combined together as the default simulation project template. This makes it possible to create simulation models very quickly and to simulate and compare different scenarios of the same construction project in parallel. 4.2 Collaborative Portal ProSIM The ProSIM platform is designed as an online web-based portal to support the communication and collaboration among all project planning members and to publish simulation model results and all related input data (Ismail et al., 2014). It facilitates the verification of all input parameters and simulation results effectively 331-7 Besides publishing simulation models, their scenarios and results, it offers the following functions: • Online management of productivity factors of various construction operations  (http://bci52.cib.bau.tu-dresden.de:3000/aws) • Online management of resource requirements and task duration definitions  (http://bci52.cib.bau.tu-dresden.de:3000/aws) • Online repository of reference process models of construction activities as BPMN models (http://bci52.cib.bau.tu-dresden.de:3000/rpms) • Multi-Model Navigator to explore and transform the content of interlinked project data (http://bci52.cib.bau.tu-dresden.de:3000/mmc) • Online viewers of various input and output data (Gantt charts, resource utilization charts, 2D animations, Calendar view, etc.) ProSIM is implemented using the modern web development framework “Ruby on Rails”. This web development framework was chosen because it is suitable for rapid development. It also emphasizes the use of well-known software engineering patterns and principles, such as active record pattern, and Model–View–Controller MVC. The Web application is deployed via Apache web server and MySQL database. 5 STUDY CASIES: 5.1 Mefisto Office Project The first demonstration and validation simulation project “Mefisto office” is a multi-storey office building. The structural work activities have been simulated based on a rough master project schedule. In this project all simulation input data was created or imported manually and the logistic (construction site layout, material delivery, etc.) and cost information were excluded. For this project 2 simulation models and various scenarios were implemented and analysed in order to: (1) Automatic generation of detailed project schedules for the whole building taking in account different construction strategies and maximal resource capacities, (2)  Simulate and optimize the structural work for short term planning  of construction phase taking in account the formwork and reinforcement work details. More details and simulation scenarios are this demonstration project are described in (Ismail and Scherer 2014).  Figure 6: The effect of changing number of workers on the of structural work duration  331-8 Fig. 6 shows the effect of changing the number of workers between 10-40 workers on the expected duration of structural work, workers utilization and the consumption of concrete for 2 floors.  All results of simulation scenarios for this project are available under: http://bci52.cib.bau.tu-dresden.de:3001/simweb/ 5.2 Mefisto Airport Terminal Project For the second demonstration project “Mefisto Airport” two simulation models based on CST toolkit were implemented and different scenarios were prepared and carried out.  The first test case was to generate automatically a detailed project schedule of construction work of the whole building based on the concept of “top-down simulation method” described in details in (Ismail 2011). The main inputs of this case are: (1) master project schedule, (2) high level reference process model which describe the logic of structure work in each floor, and (3) a set of detailed reference process models which describe the logic of structural work for different kind of building elements (slab, beam, column, etc.).  The multi-model project delivery approach and multi-model-container data exchange method have been used in order to extract all related project information and transform them to the internal data structure of the simulation model as following: • The master schedule in the multi-model container (in iTOW XML format) has been transformed into a “Task list” simulation component. Each task represents the structural works within one floor or a work-section has been linked with the high level reference process model of structural work. • The simulation related data inside the IFC model of the building were processed using MMQL, BIMFit and IFCWebServer data model server and converted to the internal data structure of the simulation database. • Link model data has been imported into simulation model in one step After the automatic generation of the detailed project schedule a “minimal project duration” scenario was carried out. In this scenario the capacity of available workers and building material was set to unlimited and only the capacity of tower cranes were considered. The aim of this scenario was to validate and test the feasibility of top-down simulation method and also to analysis the effect of changing the construction strategies and the dates of milestones in the master schedule on the ultimate minimum construction duration. The simulation model and the results of this test case are available through ProSIM under: http://bci52.cib.bau.tu-dresden.de:3000/sim_models/3 The second case study for the Mefisto Airport focused on the simulation of structural work inside one floor. The target was to analyze the effect of changing various factors like resource capacities, the interaction between production and logistic operations and construction methods (in situ concrete, precast) on the expected total duration and the resources utilization ratio. In order to simulate the logistic operations the necessary information about the construction site model was imported from a special IFC model. This model includes the following information: entry and exits gates, transport ways, tower cranes properties and location and yard storage areas. This information was mapped directly into the internal data structure of the “Construction Site” component, which convert them in turn into active and passive material flow simulation objects. With help of “4D Visualizer” component the construction site model can be generated automatically as 4D models including full movement records of crane operations and yard storage areas utilization rates. The simulation model and the results of both scenarios are available through ProSIM under: http://bci52.cib.bau.tu-dresden.de:3000/sim_models/8 6  CONCLUSION AND FUTURE WORK The target of this research was to promote a wide adoption of simulation methods to support construction project planning. Systems integration and collaboration are believed to be the key enabling technologies that drive the construction industry in improving productivity and efficiency (Shen et al., 2010). This paper 331-9 presented the design and development efforts of a process-based simulation toolkit and a collaborative platform and discussed the integration of various project data models into the simulation models using multi-models data exchange approach. It discussed also the concept of using formal process models based on BPMN in order to capture and manage knowledge in construction domain and transfer them directly into simulation models. The results obtained from demonstration projects showed the potential of using CST and ProSIM by the rapid deployment of simulation models and the flexibility of applying various scenarios. The future development will include the integration between the simulation platform and the project real data collected on site and adding more reference process models for other project types or disciplines like bridges and electric and interior work. Acknowledgements The research in this paper was enabled by the financial support of the German Federal Ministry of Education and Research (BMBF), Department of ICT under contract n° 01IA09001A, which is herewith gratefully acknowledged References AbouRizk S. 2011. A Construction Synthetic Environment Integrating Visualization and Simulation. ConVR 2011:11th International Conference on Construction Applications of Virtual Reality- pp 10-22 Aouad, G, Lee, A and Wu, S. 2006. nD modelling for collaborative working in construction. Architectural Engineering and Design Management, (1), pp. 33-44.  Akhavian,R. Behzadan, H. A. 2011. Dynamic Simulation of Construction Activities Using Real Time Field Data Collection. European Group for Intelligent Computing in Engineering Workshop Chris Hendrickson. 2000. Project Management for Construction, Carnegie Mellon University. Ismail A., Srewil Y., Scherer R.J. (2014) ‘Collaborative Web-based Simulation Platform for Construction Project Planning’, in PRO-VE 2014: Proceeding of the 15th IFIP working Conference on Virtual Enterprises, Netherlands, Amsterdam. Ismail A., Scherer R.J.2014: Integration of Simulation Data for Construction Project Planning Using a Process-based Simulation Framework, In: Proc. of the 13th International Conference on Modelling and Applied Simulation (MAS), France, Bordeaux.  Ismail, A. and Scherer, R.J. (2014) ,”Simulation of construction variations using a process-based simulation toolkit” in Scherer and Schapke(Eds.)  Information Systems in Civil Engineering – Applications, Springer , DOI 10.1007/978-3-662-44760-4_6 , ISBN 978-3-662-44759-8, Germany, pp.693–725 Fuchs S., Katranuschkov P. and Scherer R.J. 2010. A framework for multi-model collaboration and visualization. Proceedings of “eWork and eBusiness in Architecture, Engineering and Construction” conference, 14-16 Sept. 2010, Cork, Ireland. Rosemann. M. 2002. Application reference models and building blocks for management and control (ERP Systems). In, P. Bernus, L. Nemes, & G. Schmidt (Eds.) Handbook of enterprise architecture (pp. 595-615). Berlin: Springer. Schapke, S.-E.  and Scherer, R. J. 2010. A distributed multi-model based Management Information System for simulation and decision making on construction projects. Advanced Engineering Informatics Journal, Special Issues of the ICCCBE & EG-ICE10 Conference, Elsevier  Schapke S.-E. and Pflug, C.2012. Multi-models: New potentials for the combined use of planning and controlling information.  Transparent - das Magazin, vol. 37, June 2012   331-10  Fakultät Bauingenieurwesen, Institut für Bauinformatik, Prof. Dr.-Ing. Raimar J. Scherer AN INTEGRATED PROCESS-BASED SIMULATION PLATFORM FOR CONSTRUCTION PROJECT PLANNING 5th International/11th Construction Specialty Conference  Vancouver, British Columbia  Ali Ismail Raimar J. Scherer Overview •  Motivation, objectives and approach •  Process-based simulation method •  Multi-Model data exchange approach •  Construction Simulation Toolkit- CST •  Collaborative Simulation Portal- ProSIM •  Validation simulation projects •  Conclusion An Integrated process-based simulation platform for construction project planning 2/30 2015-07-12 •  Creating reliable and reusable simulation models is very complex, time consuming task  •  simulation software need very experienced simulation experts •  Set up and validation of a simulation model for a construction project need 2-3 months  Consequence: §  Simulation is not very often applied §  It cannot sufficiently handle the complexity of modern construction projects §  The benefits are not immediately obvious 2015-07-12 Problem An Integrated process-based simulation platform for construction project planning 2015-07-12 Motivation •  Support planning of construction projects through rapid set-up of simulation models and fast variation of them  Consequences: •  Developing a set of convenient tools for setting-up of simulation models based on standard data interfaces •  Developing a collaboration platform to integrate the huge and complex projects data with low-cost entry for construction industry and enable communication between design, planning and simulation experts. An Integrated process-based simulation platform for construction project planning 2015-07-12 Approach •  Process-based simulation approach Using formal business process models BPMN notation, extend by resource modelling and providing the ability to transform them into simulation process •  Reference Process Model method to capture and organize the construction knowledge •  Dynamic filter tool box (BIMfit) for task based specification in BPMN via MVD and filtering of information views from different models •  Multi Model method for data integration and interoperability of design and planning information •  Reusable simulation components (CST Toolkit) •  Collaborative simulation portal (ProSIM)  An Integrated process-based simulation platform for construction project planning Reference process models, RPM RPM are generic conceptual models based on BPMN that formalize recommended practice for a certain domain. They can be combined to complex ones. We have adopted and extended BPMN in order to capture and transform construction processes into simulation models.  An Integrated process-based simulation platform for construction project planning 6/28 2015-07-12 BPMN Simulation XML Multi Model Approach An Integrated process-based simulation platform for construction project planning 7/30 Multi Model project planning is a paradigm shift from the building centric approach toward an equivalent interlinked data models using explicit and separated link models.  A multi-model container comprises several domain models and one or more link models. It includes meta information on container, domain and link level.  Multi Model approach is integrated with CST through providing import and export facilities.  2015-07-12 Multi Model Concept FBI 2012 Bochum Kontextspezifische Kollaborationsunterstützung in kooperativen Planungsprozessen 8/28 Principle bundling of heterogeneous application models and explicit, ID-based links between their elements Multi Model Container Example FBI 2012 Bochum Kontextspezifische Kollaborationsunterstützung in kooperativen Planungsprozessen 9/28 MMC for the Mefisto Airport project – Tender phase Download link: http://bci52.cib.bau.tu-dresden.de:3000/multi_model_containers/1 Simulation platform components FBI 2012 Bochum Kontextspezifische Kollaborationsunterstützung in kooperativen Planungsprozessen 10/28 CST Toolkit Collaborative  Web Portal CST: Simulation Components CST toolkit is implemented on top of the simulation software Plant Simulation (Siemens PLM).  CST is the construction specific interface to general simulation engines. CST aims to reduce the total duration and cost of construction projects through improving the planning quality and utilization rates of resources and avoid conflicts during the construction phase. CST offers a set of simulation modelling components, which can be used in a modular way to create simulation models rapidly.  An Integrated process-based simulation platform for construction project planning 11/28 2015-07-12 Simulation modelling components 2015-07-12 TU Dresden  -  Institute of Construction Informatics   -   Prof. Raimar Scherer  12  ProSIM: Collaboration Platform TU Dresden,  12-Jul-15 Transformation of Business Process Models into Petri Nets for Building Process Simulation 13/30 ProSIM platform is designed as an online web-based portal to support the communication and collaboration among all project planning members and to publish simulation model results and all related input data.  ProSIM can be accessed at  http://bci52.cib.bau.tu-dresden.de:3000/  Validation and Study Cases •  Mefisto Office project –  18 storey office building –  Planning and simulation of constrcution work –  Reduce the total duration of construction •  Mefisto Airport Terminal Project –  Planning and simulation of logistic and construction work –  Optimize the number of key resources –  Optimize the construction site layout Access to Simulation models and resutls at: http://bci52.cib.bau.tu-dresden.de:3001/simweb/ http://bci52.cib.bau.tu-dresden.de:3000/  An Integrated process-based simulation platform for construction project planning 14/28 2015-07-12 Conclusions and future work •  Using formal process modelling and reference models in order to capture and manage knowledge in construction domain and transfer them into simulation models •  Using Multi Model approach for project data exchange •  Construction specific simulation toolkit and a collaborative platform Future work: •  Integrating the simulation platform with project real data collected on construction site •  Extending  reference process models for other project types or disciplines like bridges and interior work FBI 2012 Bochum Kontextspezifische Kollaborationsunterstützung in kooperativen Planungsprozessen 15/28 Simulation examples ICSC’15  An Integrated Process-based Simulation Platform For Construction Project Planning 16 Simulation examples ICSC’15  An Integrated Process-based Simulation Platform For Construction Project Planning 17 Simulation examples ICSC’15  An Integrated Process-based Simulation Platform For Construction Project Planning 18 Simulation examples ICSC’15  An Integrated Process-based Simulation Platform For Construction Project Planning 19 Simulation examples ICSC’15  An Integrated Process-based Simulation Platform For Construction Project Planning 20 Fakultät Bauingenieurwesen, Institut für Bauinformatik, Prof. Dr.-Ing. Raimar J. Scherer Thank you ! Management	  –	  Führung	  –	  Informa2on	  –	  Simula2on	  im	  Bauwesen	  Acknowledgements  The research in this paper was enabled by the financial support of the German Federal Ministry of Education and Research (BMBF), Department of ICT under contract n° 01IA09001A, which is herewith gratefully acknowledged Research was supported by  the  German Federatal Ministery of Research and Education Transformation path of process models into simulation models Process	  model	  System	  check	  Simula3onsmodel	  System	  check	  Process-­‐module	  Organiza3on	  specific	  Simula3ons-­‐module	  Process	  module-­‐class	  Simula3ons-­‐module	  classes	  Knowledge	  module-­‐class	  	  Knowledge	  module	  Organiza3on	  specific	  1:n 1:1 instantiieren kombinieren instantiate combination Approximation Transformation Approximation Transformation Approximation Transformation 1:n 1:n 1:n 2015-07-12 TU Dresden  -  Institute of Construction Informatics   -   Prof. Raimar Scherer  22  The hierarchical structure of model domains Workflow-­‐	  Management	  Risk-­‐	  prognosis	  Produc2on	  &	  Logis2c	  simula2on	  Layer	  1	  PCM	  Processs	  BIM	  Building	  	  CSM	  Construc2on	  Site	  ORM	  Organisa2on	  COM	  Costs	  SPM	  Specifica2ons	  TSM	  Dates	  Layer	  4	  RIM	  Risks	  STM	  Stochas2c	  FUM	  Fuzzy	  2015-07-12 TU Dresden  -  Institute of Construction Informatics   -   Prof. Raimar Scherer  23  Analyses	  models	  Combining	  model	  Addi2ve	  models	  Self-­‐standing	  models	  Addi2ve	  models	  Basic process template for single activity The basic process template will be used later to map the single tasks in BPMN into single tasks of the simulation models.  2015-07-12 TU Dresden  -  Institute of Construction Informatics   -   Prof. Raimar Scherer  24  Basic	  Process	  Template S E Prerequisites	  checker Resource	  manager Resources Other	  constraints Single	  	  ac3vity Compound process templates The compound process template is used to map compound process task of a generalized process task in a compound simulation task, detailed enough to run a simulation 2015-07-12 TU Dresden  -  Institute of Construction Informatics   -   Prof. Raimar Scherer  25  2D Animation Simulation Output 2015-07-12 TU Dresden  -  Institute of Construction Informatics   -   Prof. Raimar Scherer  26  Mefisto-Office project Mefisto- Airport project 4D Animation Simulation Output 2015-07-12 TU Dresden  -  Institute of Construction Informatics   -   Prof. Raimar Scherer  27  Building elements are colored according to activity types  (steelwork, formwork, concrete work) or work finished within time intervals (days, weeks, months) Material usage/Resources utilization Resources utilization and material usage with time Simulation Output 2015-07-12 TU Dresden  -  Institute of Construction Informatics   -   Prof. Raimar Scherer  28  Effect of changing the number of workers on the construction work duration of 2 floors 

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