WSC 2008 Final Abstracts

Simulation-Based, Optimized Scheduling of Limited Bar-Benders over Multiple Building Sites
Hoi-Ching Lam (Hong Kong Polytechnic University)

Abstract:
In the construction industry, a specialist subcontractor manages a taskforce of single-skilled laborers to work on multiple construction sites, aiming to minimize the total cost and stay profitable and competitive. This paper presents a simulation-based approach to assist the subcontractor in scheduling the application of limited laborer resources to handle jobs over multiple concurring sites. Factoring in technological constraints, repetitive building cycles, alternative method options, and the limited quantity of skilled laborers, we resort to computer power (including simulation and optimization algorithms resulting from recent research) in search of the best combination of construction methods at individual sites along with the optimum size of labor force, aimed to find the least cost for completing the jobs at all sites. A case study of barbender scheduling over three sites by use of an inhouse computer tool results in the optimum method combinations, the optimum crew size, and the optimum resource schedule.

Multi-Agent Resource Allocation (MARA) for Modeling Construction Processes
Yang Liu and Yasser Mohamed (University of Alberta)

Abstract:
Multi-Agent Resource Allocation (MARA) is a field developing solutions to the problem of distributing a number of resources amongst multiple agents. This field has interdisciplinary characteristics and relates to a wide range of applications, such as industrial procurement, scheduling and network routing. Many construction operations involve entities sharing and competing for limited resources. The decision to allocate these resources to entities usually has a significant impact on the schedule and cost of these operations. The dynamic and continuously changing nature of construction operations justifies the need for decision support tools with high adaptability and handling of uncertainty which is featured by MARA. This paper presents the main elements and techniques in MARA and discusses a sample case applying these techniques for the modeling of industrial construction assembly processes, also presents the conceptual model of the sample case and a prototype implementation of that model using Repast multi-agent simulation package.

A Dynamic Crashing Method for Project Management Using Simulation-Based Optimization
Michael E. Kuhl and Radhames A. Tolentino-Pena (Rochester Institute of Technology)

Abstract:
A dynamic simulation-based crashing method is introduced in this research to evaluate project networks and determine the optimum crashing configuration that minimizes the average project cost due to lateness penalties and crashing costs. This dynamic approach will let the user evaluate the project network to determine a crashing strategy at the beginning of the project and also during the life of the project. By reevaluating the project network possible adjustments to the crashing strategy may be identified and implemented. The output of the method includes a distribution of the project completion time, a distribution of the project total cost, and the project cost savings.

Using Situational Simulations to Collect and Analyze Dynamic Construction Management Decision-Making Data
Matthew T. Watkins, Amlan Mukherjee, and Nilufer Onder (Michigan Tech.)

Abstract:
In this paper we lay the foundations for studying decision-making in complex dynamic construction management scenarios using situational simulations as experimental testbeds. We draw on research conducted in dynamic decision making, construction data-mining and situational simulations to develop methods to study human decision-making data collected in ICDMA - a situational simulation of a real four story steel frame office building construction project. Specifically, we address challenges in the collection, organization and analysis of human subject data. We define a discipline driving the collection of human decision-making data, establish a semantics to organize the data and a simple mathematical syntax to represent it. We also present an analysis of preliminary experimental work and show that our method can be used to analyze patterns in complex construction decision-making. Finally, we present an agenda of research in construction decision-making using situational simulations that can be conducted using our proposed methods.

A Framework for Real-Time Simulation of Heavy Construction Operations
Lingguang Song (University of Houston) and Fernando Ramos and Katie Arnold (Heavy Construction Systems Specialists, Inc.)

Abstract:
This paper describes a framework of real-time simulation for modeling heavy construction operations. Compared to the traditional off-line simulation that uses stationary inputs, the capability of real-time simulation to dynamically incorporate new project data and adapt to changes of the operation environment offers the promise to improve the accuracy of project forecasting. In the proposed real-time simulation framework, dynamic data of construction operations are constantly captured and fed into a process simulation model for short-term scheduling purpose. A prototype system was developed to demonstrate the structure of the proposed framework and its feasibility. Benefits and limitations of this simulation approach and future research requirements for achieving a higher level modeling automation are also presented in this paper.

A Framework for Simulating Industrial Construction Processes
Naimeh Sadeghi and Aminah Robinson Fayek (University of Alberta)

Abstract:
In an industrial fabrication shop, such as pipe spool and steel fabrication, a product usually travels in the system in the form of raw materials or components of the product. During the fabrication process, different components are assembled together to fabricate the final product. In this paper, to increase the accuracy of modeling fabrication processes, we propose a platform that can automatically model the raw materials and the assembly process of components of a product based on the unique features of a product. For this purpose, a Special Purpose Simulation (SPS) template for industrial fabrication is developed. The platform is used to develop a simulation based decision support system using a real case study of a pipe spool fabrication shop.

Simulation and Optimization for Construction Repetitive Projects Using Promodel and Simrunner
Chachrist Srisuwanrat, Photios G. Ioannou, and Omer Tsimhoni (University of Michigan)

Abstract:
We introduce a new approach, called Relative Start and Idle Time (RSIT), to solve probabilistic scheduling problems of construction repetitive projects. RSIT is a process of determining a range of input variables and employing optimization through simulation to solve scheduling problems. RSIT reduces the modeler’s effort because it does not heavily rely on manual trial-and-error. The two primary advantages of this approach are: (1) it does not require additional solving algorithm code and (2) it does not impose unnecessary limitations on the simulation model in order to solve the scheduling problem. The new approach is presented in detail and applied to a real past repetitive project of four four-story buildings. Results from RSIT are evaluated and compared to the results from a deterministic approach. The example is modeled in ProModel and optimized in SimRunner.

Distributed Agent-Based Simulation of Construction Projects with HLA
Hosein Taghaddos, Simaan AbouRizk, Yasser Mohamed, and Ivan Ourdev (University of Alberta)

Abstract:
Simulation techniques can provide a resource-driven schedule and answer many hypothetical scenarios before project execution to improve on conventional project management software applications for large-scale construction projects. However, the current process of simulation and optimization of resource utilization is a time consuming process especially for large-scale projects. This study employs High Level Architecture (HLA) to develop distributed agent based simulation models. These models are composed of several individual modeling components (federates) that can cooperate with each other for the simulation model (interoperability). These federates are developed in a generic way for reuse on future construction projects. A number of agent-based federates are considered for managing various aspects of the project and to enhance the performance of the simulation model. This framework is illustrated using two case studies, module assembly yard and tower crane, that investigate the feasibility of the proposed approach.

Optimization of Multi-Project Environment (OPMPE)
Lokman Hossain and Janaka Ruwanpura (University of Calgary)

Abstract:
Construction business is project oriented and that is why every organization is dependent on projects. Typically they undertake multiple projects with limited multiple resources and information. Most importantly they need to take continuous and quick decisions to keep it going. The reason behind this is lack of tools and structured approach that can efficiently deal with multi-project environment (PME). Resulting is problem of wrong project selection, project slippage and under/over utilization of scares resources. This paper presents a simulation model (OPMPE) for optimizing MPE. The model is capable of analyzing and predicting future problems, assessing the cumulative impact and generates valuable statistics and information for quick decision-making. It will work together with the available scheduling tools and will help strengthening the overall planning and execution system for MPE. The application and of the model is demonstrated using a collection of real project data for building construction.

Using Operation Process Simulation for a Six Sigma Project of Mining and Iron Production Factory
Undram Chinbat and Soemon Takakuwa (Nagoya University)

Abstract:
The use of the Operation Process Simulation (OPS) for Six Sigma Projects (SSP) can illustrate visual display of the process by enabling to define, measure, analyze and improve the current process virtually but realistically. This paper investigates the quantitative benefits of using the Design for Six Sigma (DFSS) technique for a SSP in a Mining and Iron Production Factory (MIPF). The DFSS was deployed through five distinct phases: DMAIC, for optimizing the current MIPF as a first part of the research. The second part of the research investigates the possibilities of developing the deliverables of the DMAIC for a DMADV for implementing a new MIPF. Use of the OPS in all phases of the DMAIC has provided highly effective and accurate prediction for factory process improvement. Furthermore, the paper explored the effective possibilities of developing the deliverables of the DMAIC for the DMADV for building new MIPF.

Photo-Based 3D Modeling of Construction Resources for Visualization of Operations Simulation: Case of Modeling a Precast Façade
Fei Dai and Ming Lu (Hong Kong Polytechnic University)

Abstract:
3D models of building components or construction resources have been largely created by computer-aided-design (CAD) or by proprietary code for virtual reality development. Such 3D modeling methods entail accurate definition of points, lines and their relationships in the spatial coordinate system. Unlike CAD modeling, the surveying technique of photogrammetry takes a completely different approach by deriving metric information about an object through measurements conducted on photographs of the object. The very basic technique of photogrammetry is effective and computationally simple. With much less efforts, digital cameras and photogrammetry software have made possible 3D reconstruction of an object in digital form (coordinates and derived geometric elements). The resultant 3D models may well satisfy application needs in construction simulation visualization. In this paper, we introduce computing algorithms of photogrammetry and present an application of modeling a precast facade in 3D based on digital pictures taken at a building site.

Simulation and Visualization of Traffic Operations in Augmented Reality for Improved Planning and Design of Road Construction Projects
Amir H Behzadan (The City University of New York) and Vineet R Kamat (University of Michigan)

Abstract:
This paper describes research that investigated the application of 3D Augmented Reality (AR) for animating traffic simulation models in real-time to support the planning and design of road construction projects. Traditional 3D visualization applications use Virtual Reality (VR) to visualize traffic simulations. The significant time and human resources required to collect and incorporate statistical data about existing traffic volume and pattern can be a major drawback to the application of VR in studying the possible effect of traffic on planned construction. At the same time, the final visual output is often unconvincing as phenomenon such as unpredictable motion of pedestrians and incoming vehicles cannot be effectively represented in a VR animation. In this research, a new AR-based approach to create real time interactive traffic animations is introduced. This approach takes advantage of wireless communication techniques to facilitate continuous positional and orientation data transfer between moving vehicles and an AR animation.

A Simulation Template for Modeling Tunnel Shaft Construction
Fangyi Zhou (S.M.A. Consulting Ltd.), Simaan M. AbouRizk (University of Alberta) and Siri Fernando (City of Edmonton Asset Management and Public Works, Drainage Services)

Abstract:
This paper presents the design and development of a template for analyzing shaft construction projects. It is suitable for integration with the existing Tunneling template of the Simphony modeling environment to provide users a complete, functional and more flexible simulation tool for tunnel construction. The developed system will be a powerful tool for decision-making and evaluating the feasibility of tunnel construction methods, in identifying and allocating site spaces, and in the visualization of tunneling construction sites as a mean of describing the site layout to other involved parties. Further, it assists users in modeling several scenarios without changing the developer’s code or the base of the tool, and it does not require integration with any other modeling templates. This template design is then applied to a case study involving the construction of a circular tunnel shaft, part of the North Edmonton Sanitary Tunneling (NEST) system in Edmonton, Canada.

An Integrated CAD and Simulation Model for Concrete Operations
Aly Abdel Fattah and Janaka Ruwanpura (University of Calgary)

Abstract:
Pouring a concrete raft slab is a classic problem in down-town projects because it requires special arrangements to be made with city authorities to close the area around the project during the operation. City authorities allow this only during the weekends that puts a lot of pressure on construction staff to finish pouring the concrete in a limited amount of time. In this paper, a simulation model for predicating the pouring time is introduced. This integrated model consists of: Special Purpose Simulation (Simphony), Microsoft Access, Visual Basic for Application (VBA) and AutoCAD software. Moreover, in this paper the sensitive parameters are analyzed and recommendations for choosing pouring concrete sub-contractors are provided. Additionally the proposed model is applied to a practical case for defining the required time for pouring a lower raft slab for “The Bow” project in downtown Calgary.

Simulation of Modular Building Construction
Paul Joseph Knytl, Osama M Mohsen, Basel Abdulaal, Jacek Olearczyk, and Mohamed Al-Hussein (University of Alberta)

Abstract:
Modular construction has the advantage of producing structures quickly and efficiently, while not requiring the resources to build a structure to be co-located with the construction site. Large modules can be produced in quality controlled environments, and then shipped to the construction site and assembled with minimal labor requirements. An additional advantage is that once the modules are on-site, construction can proceed extremely quickly. This is ideal for situations where compressed schedules are required in order to meet client’s time constraints. This paper examines using software simulation, specifically Simphony.NET, in the design and analysis of the construction process. This is done both before and after project execution to predict productivity and duration and also to allow for exploration of alternate construction scenarios.

Harnessing the Power of Simulation in the Project Management / Decision Support Aspects of the Construction Industry
Gunnar Lucko (The Catholic University of America), Perakath C. Benjamin (Knowledge Based Systems, Inc.) and Michael G. Madden (M. Madden OR & DES Consulting)

Abstract:
This paper reviews the history of construction simulation systems in light of their graphical representation of complex scenarios. The simulation of construction operations has been a growing field of research over the last several decades. Since the introduction of the first simulation system, which was based on the activity cycle diagram paradigm of modeling, numerous additional tools have been introduced, each building on and expanding the modeling and analytical capabilities of previous approaches. However, despite such rich body of knowledge, which by now is expanding into areas such as visualization, animation, and virtual reality applications for construction project management, the beneficial application of simulation in practice has been marginal. This paper describes both historical and practical reasons for this situation and presents an ontology-based approach that can harness existing information in construction project management, especially the scheduling function, and has the potential to significantly improve its operational planning and optimization.

Identifying Significant Factors Affecting Request for Information (RFI) Process Time
Chang-Sun Chin and Jeffrey S Russell (University of Wisconsin, Madison)

Abstract:
The research is to illustrate how to identify the significant factor(s) affecting the Request For Information (RFI) process cycle time in the context of queueing behavior. Among three different factors involved in the general queueing model (i.e. variability factor, utilization factor, and average process time), the variability factor was selected and investigated to see how variations affect the process cycle time under different conditions along with the batching effect. In order to determine the levels of factors, a set of RFI data was statistically analyzed. Based on the selected factors with levels determined, different scenarios were developed and simulation study was conducted so as to see how the system performs differently. Then, results of simulation were analyzed using the DOE in order to identify the most significant factor(s) which affects the current process cycle time.

Simulation as a Tool for Life Cycle Cost Analysis
Khaled Shahata (UMA Engineering Ltd.) and Tarek Zayed (Concordia University)

Abstract:
Life cycle cost is an essential approach to decide on alternative rehabilitation strategies for infrastructure systems. Monte Carlo simulation approach is used to develop a stochastic life cycle cost (SLCC) model and methodology in order to compare different rehabilitation scenarios/alternatives for infrastructures, such as water mains. The presented research in this paper identifies several rehabilitation methods for water mains, which are classified into three main categories: repair, renovation, and replacement. The developed model helps academics and practitioners (e.g. municipal engineers) to predict the suitable new installation and/or rehabilitation programs as well as their corresponding costs, thereby, to avoid any unpleasant surprises.

Tunnel_Sim: Decision Support Tool for Planning Tunnel Construction Using Computer Simulation
Mohamed Marzouk, Moatassem Abdallah, and Moheeb El-Said (Cairo University)

Abstract:
Tunnel construction are essentially infrastructure projects that includes many interfered and sophisticated tasks. This paper presents a decision support tool, Tunnel_Sim, for planning tunnel construction projects using computer simulation. The proposed tool assists contractors in estimating time and cost, required for the construction of tunnel projects. Five construction techniques are coded in the proposed tool to capture the construction of open/closed rectangular cross-section tunnels and circular cross-section tunnels. The decision support tool divides the construction of tunnels into working zones. It estimates the total duration and cost for each zone. The proposed tool selects the best construction technique from a set of alternatives based on a decision making method that utilizes fuzzy numbers. An application example is presented to demonstrate the characteristics of the proposed Tunnel_Sim.

Calculating Float in Linear Schedules with Singularity Functions
Gunnar Lucko and Angel Alberto Peña Orozco (The Catholic University of America)

Abstract:
This paper presents an exact approach of calculating float for each activity in linear schedules. It is based on singularity functions, which have been used previously to determine the criticality of activities in said schedules. Singularity functions are versatile in that they can describe multiple changes of productivity within each activity, can be evaluated by hand if desired, and thus provide the basis for a complete schedule analysis methodology. Following a brief review of how activities and their buffers are modeled with singularity functions, this paper examines types of float that are commonly encountered in the critical path method of scheduling and develops an equivalent approach for linear schedules. An example from the literature is used to demonstrate the application of the new float analysis.