WSC 2002 Final Abstracts

Lean Construction and Simulation
Daniel W. Halpin and Marc Kueckmann (Purdue University)

Abstract:
This paper explores the relationship between simulation and the emerging topics of Lean Thinking and lean construction. The ideas which have motivated the evolution of lean construction concepts are presented. The use of simulation as a means of evaluating the benefit of using lean construction techniques is discussed. Two examples of lean thinking based re-design of common construction processes are described and evaluated using construction process simulation. The paper is designed to promote consideration of the similarities between simulation based process improvement and process re-design related to the application of the principles of lean construction.

Optimal Construction Project Planning
Simaan AbouRizk and Yasser Mohamed (University of Alberta)

Abstract:
The nature of the construction industry combined with the lack of appropriate techniques and technologies suitable for construction work are among the main reasons for inadequate industry performance. Researchers need to develop a better understanding of the construction industry and develop approaches and technologies that will enable construction companies to do a better job in estimating, planning, and control. A production-based framework is proposed in this paper to address some of the challenges in managing construction projects. The framework is based on a number of components, which collectively represent an integrated approach for planning and execution of construction projects. This paper focuses on the simulation component of the framework and highlights the features currently available in Simphony as a leading construction simulation platform. It also addresses the main challenges and requirements for extending its capabilities to fit within the envisioned framework.

Special Purpose Simulation Modeling of Tower Cranes
Bradford J.A. Appleton and John Patra (PCL Construction Inc.) and Yasser Mohamed and Simaan AbouRizk (University of Alberta)

Abstract:
Historically, simulation tools have only been used and understood by the academic community. Special Purpose Simulation (SPS) techniques have introduced computer modeling to the industry, resulting in reduced model development time and a user-friendly environment. This paper describes the special purpose simulation template, which is based on the tower crane operations performed by PCL Constructors Inc. On-site management of the tower crane resource is based on prioritized work tasks that need to be performed within a set period of time. Traditional SPS modeling techniques use ‘relationship logic links’ to represent the logic contained in the modeled system. As the number of work tasks increases for the tower crane resource, the model complexity using traditional simulation techniques becomes unmanageable, resulting in limited acceptance by industry practitioners. The tower crane template uses ‘priority rating logic’ to replace the ‘relationship logic links’. Evaluation of the tower crane operations at the Electrical and Computer Engineering Research Facility (ECERF), being constructed in Edmonton, is used to illustrate the advantages of using the ‘priority rating logic’ modeling approach for tower crane operations. The simulation model analyzes the ECERF tower crane production cycle yielding outputs for total duration, crane utilization, and lift activity hook-time analysis.

Simulation-Based Analysis of Handling Inbound Containers in a Terminal
Sgouris P. Sgouridis (Private Practice) and Demos C. Angelides (Aristotle University of Thessaloniki)

Abstract:
The continuing growth of marine container transport, as well as, the complexity in the analysis of terminal port operations has created an ideal area for applying computer simulation. This paper focuses on the handling of incoming containers transported on trucks in an "All-Straddle-Carrier" system. All major processes are reproduced by the simulation model. Input data includes parameters of space, speed and arrival frequency in a generic format, so as the model is adjustable to any situation. Analyzing the model for periods of model time ranging from a day to a week can give insight to the service level provided by any given port configuration. The simulated system can be used as a planning and a process improvement tool. In the development of the simulation model an object-oriented environment is used. It proves quite effective, resulting in a reliable and adjustable model.

Application of Simulation Models in Airport Facility Design
Naren Doshi and Robert Moriyama (Greater Toronto Airports Authority)

Abstract:
Lester B. Pearson – Toronto International Airport is undertaking a $4.4B development program comprising a new 390,000 sq. m. terminal building (replacing two aging terminals), three new runways, cargo facilities, a central utilities plant, and an expanded road system and parking facilities. This activity is proceeding while the airport continues to operate and while requirements evolve in response to rapid changes in the airline industry. The airport has used and continues to use airport simulation models to assist in the development of program requirements and to validate design. For example, computer models have been used to generate population estimates to determine impacts on HVAC requirements and to simulate queuing at check-in counters and pre-board security screening points. This paper will discuss calibration methods and the application of simulation results in the design process. Finally, the impact of the changed environment since September 11, 2001 on airport design will be discussed.

Simulation Modeling and Optimization of Stockyard Layouts for Precast Concrete Products
Ramesh Marasini and Nashwan Dawood (School of Science and Technology, University of Teesside)

Abstract:
Stockyard is a hob of information that reflects the production, stock and sales of precast concrete products. The stockyard layout plays an important role in storage and retrieval of the products. Stockyard layout planning offers a complex task as large number of products are involved with different handling and storage requirements, and large stock is inevitable due to seasonality of demand. The major issues in planning stockyard layout include the proper design of stockyard space with roads and aisle networks and dynamic allocation of products to storage locations. A prototype "SimStock", an integrated process simulation model, was developed for planning and optimization of stockyard layouts for precast concrete products. The development of the prototype, its capacities and strengths with a case study are discussed.

Lead Time Reduction via Pre-Positioning of Inventory in an Industrial Construction Supply Chain
Kenneth D. Walsh (San Diego State University), James C. Hershauer (Department of Management), Tobi A. Walsh (Department of Supply Chain Management), Iris D. Tommelein (Construction Engineering and Management Program) and Anil Sawhney (Del E. Webb School of Construction)

Abstract:
Lead time reduction is a key concern of many industrial buyers of capital facilities given current economic conditions. Supply chain initiatives in manufacturing settings have led owners to expect that dramatic reductions in lead time are possible in all phases of their business, including the delivery of capital materials. Further, narrowing product delivery windows and increasing pressure to be first-to-market create significant external pressure to reduce lead time. In this paper, a case study is presented in which an owner entered the construction supply chain to obtain and pre-position key long-lead materials. The materials were held at a position in the supply chain selected to allow some flexibility for continued customization, but dramatic reduction in the time-to-site. Simulation was used as a tool to consider time-to-site tradeoffs for multiple inventory locations so as to better match the needs of the construction effort.

Contributors to Lead Time in Construction Supply Chains: Case of Pipe Supports Used in Power Plants
Roberto J. Arbulu and Iris D. Tommelein (U.C. Berkeley), Kenneth D. Walsh (San Diego State University) and James C. Hershauer (Arizona State University)

Abstract:
This paper describes process models that characterize the design phase in the supply chain of pipe supports used in power plants. The models are used to study how production system design factors such as batching, uncertainty, and multitasking throughout this phase hamper supply chain performance. These factors all cause an increase in lead time. The models build on the STROBOSCOPE discrete-event simulation engine and illustrate several deterministic and probabilistic simulation scenarios including different batch sizes, uncertainty levels, and allocation percentages of shared resources. Based on the analysis of the simulation results, this paper recommends performance improvements not just in the supply chain of pipe supports but generally in the delivery of capital projects.

Process Mapping of Residential Foundation Slab Construction Processes
Howard Bashford, Anil Sawhney, and André Mund (Arizona State University) and Kenneth Walsh (San Diego State University)

Abstract:
With the purpose of mapping residential foundation slab construction processes, the authors collected the necessary process mapping information. After the completion of the process mapping for several common residential foundation slab construction processes, the team then used the process maps to identify potential process improvements and documented these in new, revised process maps. The residential foundation slab construction process mapping effort coupled with process simulation demonstrated the existence of opportunities for residential foundation slab construction process improvements. This has motivated the homebuilder partners to further pursue the issue by developing a residential foundation slab construction process to a stage where several prototype foundation slabs can be built. This report provides information on all steps accomplished and all issues involving the process mapping effort.

Evaluation of Policies for the Maintenance of Bridges Using Discrete-Event Simulation
Srinath Devulapalli (Virginia Polytechnic Institute & State University) and Julio C. Martinez and Jesus M. de la Garza (Virginia Polytechnic Institute and State University)

Abstract:
The complexities and costs associated with preserving the nation's bridge infrastructure demand innovative approaches to analysis of data and prediction of future bridge conditions. Several Bridge Management systems (BMS) have come into existence following the ISTEA act of 1991. The policy analysis module of BMS systems developed is restricted to analytical methods. With the availability of modern infrastructure, realistic simulation models are being developed in several fields. This leads to the question of whether reasonably realistic and practical discrete event simulation (DES) based policy analysis tools can be developed? A DES model was developed for the Salem district of Virginia using a simulation package, STROBOSCOPE. This simulation model can be used to simulate the bridge network behavior under different policies and observe the impact on the health of the network making it a useful tool for decision-making. The tool can enable the formulation and testing of different bridge maintenance policies.

Comparison of Simulation-Driven Construction Operations Visualization and 4D CAD
Vineet R. Kamat and Julio C. Martinez (Virginia Tech)

Abstract:
Several recent research efforts in visualizing construction are rooted in scheduling. They involve linking activity-based construction schedules and 3D CAD models of facilities to describe discretely-evolving construction "product" visualizations called 4D CAD. The focus is on communicating what component(s) are built where and when. The construction processes or operations actually involved in building them are usually implied. Ongoing research at Virginia Tech focuses on designing automated, simulation-driven methods to visualize, in addition to evolving construction products, the operations and processes that are performed in building them. In addition to what is built where and when, the effort is concerned with visualizing who builds it and how by depicting the interaction between involved machines, resources, and materials. This paper expounds the differences in concept, form, and content between 4D CAD and dynamic 3D visualization of operations simulations. An example of a structural steel framing operation is presented to elucidate the comparison.

Optimization of the Waste Management for Construction Projects Using Simulation
Mala Chandrakanthi, Janaka Y. Ruwanpura, Patrick Hettiaratchi, and Bolívar Prado (University of Calgary)

Abstract:
Growth in construction activities increases the amount of construction waste generated. Recycling of construction waste is an important component of environmentally responsible construction, as it reduces the amount of waste directed to landfills. In addition, it enhances the resource recovery for future construction work. A model is presented in this paper to predict waste generation rates, as well as to determine the economic advantages of recycling at construction sites. A future advanced version of the model can be applied to any construction site to; determine the amount of daily waste generation, resource and time requirement for sorting and transporting of recyclables. The model, therefore, is a valuable tool for construction managers interested in asserting the viability of recycling projects.

Simulation based Project Selection Decision Analysis Tool
Gary Powers (Nova Chemicals Ltd.), Janaka Y. Ruwanpura (University of Calgary), Garry Dolhan (EVANS Consoles Inc. ) and Martin Chu (University of Calgary)

Abstract:
Project Selection is the process of evaluating individual projects, to choose the right project based on an analysis so that the objectives of the company will be achieved. It involves a thorough analysis including the most important financial aspect to determine the most optimum project among all the alternatives. Some projects have high uncertainty, and therefore simulation based project selection decision analysis could evaluate the projects with a greater confidence. The model presented in the paper shows a special purpose simulation tool for project selection based on influences that govern the project selection process. A graphical and hierarchical approach is adopted for the non-simulation experts to use the model to derive the expected results for project selection process and decision making under uncertain conditions.

Project Management – Critical Path Method (CPM) and PERT Simulated with ProcessModel
LeRoy F. Simmons (Loyola College)

Abstract:
ProcessModel simulation allows the activity times of a project to be represented by a variety of distributions and further the resulting project time may also be represented by a variety of distributions. This is a significant improvement over the traditional methods of CPM and PERT. Program Evaluation and Review Technique (PERT) takes the CPM network and adds distributions to represent the activity times of the project. CPM assumes the activity times to be constant, which is not likely in the real world. PERT assumes the activity times of the project to be distributed as Beta distributions and the resulting project time to be a Normal distribution. This is better than assuming them to be constant, but these assumptions are needlessly restrictive. This paper demonstrates how simulation with ProcessModel can remove these needless restrictions.

Selecting Earthmoving Equipment Fleets Using Genetic Algorithms
Mohamed Marzouk and Osama Moselhi (Concordia University)

Abstract:
This paper presents an application of simulation optimization in construction utilizing genetic algorithms. The paper focuses on the use of genetic algorithms (GA) as a tool for optimizing the total cost of earthmoving operations accounting for available equipment models to contractors and their corresponding quantities. The developed genetic algorithm has a powerful computational utility that increases its efficiency. The fitness of generated chromosomes is calculated utilizing a simulation engine dedicated for earthmoving operations which is dynamically linked to the developed genetic algorithm. The impact of the algorithm’s control parameters on its conversion is also examined. A numerical example is presented to illustrate the capabilities of the developed algorithm in selecting near-optimum fleet configurations.