Productivity Analysis of Construction Operations

An interactive system for analysis of construction operations is proposed. The analysis is carried out in the context of various work modules which address quantity development, resource definition, and production and cost analysis. The quantity work module generates quantities based on information available in the design documents. The resource definition module receives and stores data regarding the labor∕equipment combination to be used to execute work tasks. This module provides the user with a set of standard useful construction process models. For each construction operation to be analyzed, the terminal describes the standard models. The user makes input of a set of parameters for process keyname, quantity, work task durations, number of resources, production capacity of each unit, and cost per hour of each unit to the standard model to be used. Using input from the resource definition module, the productivity and cost analysis module generates production rates and unit costs based on process simulation using CYCLONE methodology.     

Generic Process Mapping and Simulation Methodology for Integrating Site Layout and Operations Planning in Construction

The present research is intended to address dynamic construction-process simulation methods, with a focus on how to effectively model resource transit among various activity locations in the site system. Following a review of basic simulation paradigms and recent research developments, we propose a new process mapping and simulation methodology for modeling construction operations. The simulation algorithm is presented and the process mapping procedure is illustrated step by step using an earth-moving example featuring technology and resource constraints. It is straightforward to convert the resultant process mapping model describing workflows and resource flows over site locations into a simulation model. A STROBOSCOPE model is formed for the same problem definition to contrast and cross-validate our methodology with the established activity cycle diagram-based modeling approach. One additional case of modeling the concreting site operations by the hoist and barrow method is also given to demonstrate the application of the proposed methodology in practical settings.     

Modeling Time-Constraints in Construction Operations through Simulation

Construction operations often face time constraints that influence the execution of activities, which are not addressed enough when modeling through general discrete-event simulation. This paper describes a simulation-based methodology to handle the time constraints including the cyclical break, preemption, and overtime use. In consideration of the variable number of breaks or variable break duration for different activities, an algorithm to determine the execution of the time-constrained activities is proposed, in which the concepts of time cycle and time window are introduced. The proposed algorithm is incorporated with an activity scanning simulation strategy to develop a construction simulation for modeling the time-constrained construction operations. Some examples are presented to illustrate and validate the algorithm, and highlight the effectiveness of the developed construction simulation. The study provides an alternative to improve construction simulation in modeling of the time-constrained construction operations and is expected to assist researchers or practitioners at analyzing or planning construction operations.     

Particle Swarm Optimization-Supported Simulation for Construction Operations

This study proposes an integration of particle swarm optimization (PSO) and a construction simulation so as to determine efficiently the optimal resource combination for a construction operation. The particle-flying mechanism is utilized to guide the search process for the PSO-supported simulation optimization. A statistics method, i.e., multiple-comparison procedure, is adopted to compare the random output performances resulting from the stochastic simulation model so as to rank the alternatives (i.e., particle-represented resource combinations) during the search process. The indifference zone and confidence interval facilitate consideration of the secondary performance measure (e.g., productivity) when the main performance measures (e.g., cost) of the competing alternatives are close. The experimental analyses demonstrate the effectiveness and efficiency of the proposed simulation optimization. The study aims to providing an alternative combination of optimization methodology and general construction simulation by utilizing PSO and a statistics method so as to improve the efficiency of simulation in planning construction operations.     

Framework for Building Intelligent Simulation Models of Construction Operations

Modeling and analyzing construction operations using simulation techniques allows researchers to capture the uncertainty and randomness usually associated with these operations and can thus be an effective tool for analysis and improvement. However, the effort and knowledge required to build simulation models and experiment with them tend to limit the use of simulation in construction. A common recommendation for removing this obstacle found in the literature leans towards developing simulation tools that reduce model development and experimentation time on the construction engineer’s side by packaging most of the knowledge required into the tool itself. Such “intelligent” simulation modeling tools may significantly impact the way construction engineers use simulation techniques in day-to-day decision?making. This paper presents a framework that extends and formalizes this recommendation by providing the foundation for building intelligence into simulation objects. The proposed framework provides the structure necessary for building intelligence and autonomy into simulation objects and permits a further reduction in the knowledge required to experiment with simulation models. This approach also automates model modification, not only through changes in numeric parameters, but through topological model changes as well, which may assist the model user in making many decisions throughout the different phases of simulation experimentation.     

Six Sigma-Based Approach to Improve Performance in Construction Operations

Many researchers and project managers have attempted to improve project performance by applying new philosophies such as lean principle, just-in-time, pull scheduling, and last planner. However, very little research has been conducted on setting definite quantitative goals for performance improvement while considering the defect rate involved in the construction operations. This research explores practical solutions for construction performance improvement by applying the six sigma principle. This principle provides the metrics required to establish performance improvement goals and a methodology for measuring and evaluating improvement. The proposed approach is expected to achieve more reliable workflows by reducing process variability to fit in a desirable range—thereby improving the overall performance through the evaluation of the quality level in current construction operations. To verify the suggested methodology, two case studies have been presented and process simulation analyses are performed to observe the performance changes based on the six sigma principle. Critical total quality control, as the sigma level rises, is also discussed.     

Application of Fuzzy Logic to Simulation for Construction Operations

This paper describes the application of fuzzy logic to discrete event simulation in dealing with uncertainties of construction operations. The uncertainties in the quantity of resources required to activate an activity are modeled with fuzzy sets in linguistic terms. The fuzzy logic if-then rule is built to control the activation of activities. The duration of the activity that varies with the quantities of resources involved is determined through the fuzzy logic rule-based model. The fuzzy logic control of activities is incorporated with the activity scanning simulation strategy to implement the fuzzy simulation system for construction operations. In addition, the fuzzy activity element is adopted in the graphical modeling process. Examples are given that illustrate uses of the fuzzy simulation system and the impact of flexible demand of resources on productivity.     

RISim: Resource-Interacted Simulation Modeling in Construction

Discrete-event simulation is an effective approach to analyze construction operations. However, it is usually time-consuming and knowledge demanding to develop a practical simulation model, and thus not cost-effective due to the uniqueness and relatively short life of construction projects. The capability of discrete-event simulation modeling has not been popularly recognized by site managers until recently. A clear and explicit solution is to simplify and speed up the model development cycle, so as to enable users without much knowledge of simulation technology to easily generate a model in a relatively short period of time. In this paper, a resource-interacted simulation (RISim) modeling approach is presented, which adopts a resource oriented methodology to promote an intuitive feel to simulation modeling. In RISim, an operation is modeled in two abstraction levels—namely, the resource level and process level. An operation is viewed as a collection of resources and their interactions. Complex resources and simple resources are used to respectively represent resources with or without their own processes. The operation logic is mainly represented with internal complex resource flows, which are integrated by simple resource flows between complex resources. Resource flows can be easily conceived by site managers, enabling them to build up the logic naturally and simply. A resource library is used to implement resource reusability. Finally, an example in concrete delivery operation illustrates the methodology of resource-interacted simulation modeling and its potential for “plug-in and simulate.”     

Discrete-Event Simulation-Based Virtual Reality Environments for Construction Operations: Technology Introduction

The next logical evolution of discrete-event simulation (DES) technology for construction is for simulations and animations to run concurrently and in a manner that allows interaction with the animation to affect the course of events in the simulation. This effectively enables the creation of virtual environments with logic based on DES models, something that recent research efforts have made possible. This paper introduces this technology with the help of a case study. In particular, the paper presents how interactivity can improve the process of model validation in simulation studies, which is a critical step in achieving model credibility. Via a complex earthmoving operation, a construction engineer can use real-time interactivity to create situations of interest and study the model’s response to those, and thus validate that the response is appropriate. These capabilities can significantly enhance the process of model validation, thereby adding to the value of DES for practical use in operations planning and design.     

Activity Object-Oriented Simulation Strategy for Modeling Construction Operations

The application of an object-oriented (OO) approach including the OO modeling concept and the OO programming mechanisms to develop an activity object-oriented (AOO) simulation strategy for modeling construction operations is introduced. After discussing simulation strategies generally used for construction simulation and analyzing the problems related to the simulation strategies, the AOO simulation strategy that guides modeling or controls simulation experiments for construction simulation is introduced. The AOO simulation strategy considers activities to be objects and is able to overcome some pitfalls that result from other general simulation strategies. In addition, the AOO graphical modeling interface associated with the AOO simulation strategy is described. Finally, comparisons of the graphical model or the simulation results of the AOO simulation system with other simulation tools are illustrated.     

Research in Modeling and Simulation for Improving Construction Engineering Operations

Construction simulation, a fast-growing field, is the science of developing and experimenting with computer-based representations of construction systems to understand their underlying behavior. This paper provides a history of construction simulation theory, explores the CYCLONE modeling methodology and its major subsequent developments, examines the development of the Simphony.NET and COSYE modeling environments and their functionality as more generic simulation platforms, and reviews effective strategies for applying simulation in construction. A construction simulation case study is presented that illustrates one successful approach for adopting simulation technology in the industry and outlines the benefits to industry of integrating these technologies. The paper provides an overview of long-term simulation initiatives leading to the next generation of computer modeling systems for construction, where simulation plays an integral role in a futuristic vision of automated project planning and control.     

Iconic Animation for Activity-based Construction Simulation

This paper discusses the development of an animation tool for the activity-based construction (ABC) modeling and simulation system. The tool uses an activity-based network diagram, i.e., ABC simulation model, as the animation background image, and uses precreated two-dimensional (2D) iconic images for simulation entities (e.g., resources). The animation process displays the queuing status and dynamic movements of 2D iconic images on the background. It also distinguishes active and idle states of resources and activities. Dynamic reports are available for selected activities with graphs including the production rate and utilization of involved resources. From visualizing the change of status of a simulation process and dynamic interaction between simulation entities in the process, the user can better understand the dynamic nature of the construction process. Animation provides an avenue to demonstrate how dynamic operations are simulated. It also provides an effective tool for the user to verify a simulation model and to validate the obtained simulation results. Compared to other systems, the ABC animation does not require any extra effort in addition to the ABC simulation model constructed for simulation purposes. Therefore, the presented technology greatly reduces the time and cost for achieving animation. A variety of useful information can be observed through animation, and is illustrated using two construction examples.     

Integrating Construction Operation and Context in Large-Scale Construction Using Hybrid Computer Simulation

This research proposes a hybrid simulation approach based upon the principles of system dynamics (SD) and discrete event simulation (DES), which facilitates a better understanding of complex interactions among various processes in large-scale construction. The significance of the construction context that interacts with construction operations is highlighted, and a hybrid SD-DES approach is proposed as a means to capture the feedback between the two. In particular, this paper focuses on how to seamlessly integrate SD and DES within the framework of a modeling perspective. For the purpose of substantiating the discussion, a pipeline installation process is modeled using the proposed hybrid approach, with specific consideration given to how the approach can serve to address complex interactions between operation and context.     

Four-Dimensional Visualization of Construction Scheduling and Site Utilization

Four-dimensional (4D) models link three-dimensional geometrical models with construction schedule data. The visual link between the schedule and construction site conditions is capable of facilitating decision making during both the planning and construction stages. The emphases of these 4D developments have often been placed at the level of construction components. Practical features assisting site management are at times lacking in the following areas: (1) generation of site usage layouts; (2) estimation of quantities of construction materials; and (3) cost evaluation. In order to pinpoint these deficiencies, the objective of this work is to enable visual study of the effects of job progress on the logistics and resource schedules. This paper presents a 4D visualization model that is intended both to help construction managers plan day-to-day activities more efficiently in a broader and more practical site management context and to thereby add to our knowledge and understanding of the relevance of modern computer graphics to the responsibilities of the construction site manager. A brief site trial of the software is described at the conclusion of the paper.     

Application Framework for Mapping and Simulation of Waste Handling Processes in Construction

This research is focused on modeling waste-handling processes in construction, with particular emphasis on how to map out and simulate on-site waste sorting processes. The research proposes an application framework for (1) guiding the development of process mapping models and simulation models; and (2) further assessing the cost effectiveness of on-site waste sorting efforts under practical site constraints (such as labor resource availability, time control on refuse chute usage, and limited working area space in a building site). The connection has been established between the mapping and simulation techniques in the context of modeling waste handling processes in construction sites, such that the process flowchart resulting from the mapping technique can serve as convenient model input to facilitate the creation of a “dynamic” operations simulation model. A case study of the on-site waste sorting method with one refuse chute for waste classification is presented to demonstrate the complete application framework spanning (1) process mapping; (2) mapping-to-simulation model conversion; and (3) method optimization based on valid simulations.     

Exponential, Gamma, and Power Law Distributions in Information Flow on a Construction Site

This paper examines the statistical distributions of interarrival and response times for construction-site correspondence. Data from a number of construction projects are analyzed and hypotheses are proposed and tested to link the probability distribution to the type of correspondence. Although the commonly assumed exponential distribution of interarrival times is found to be accurate for all types of correspondence, the response times for different types of correspondence follow different distributions depending on the type of correspondence. In particular, a power law relationship is observed between incidence frequency and response time for requests for information. Knowing the statistical distributions for a class of events helps managers forecast future work and manage risk. Simulation models used by practitioners and researchers for various project management goals are also improved by incorporating appropriate statistical distributions for generating various events.     

Construction Engineering Requirements for Integrating Laser Scanning Technology and Building Information Modeling

Laser scanning for rapid spatial data acquisition is an established technology in the architecture, engineering, and construction (AEC) sector with a wide range of applications. An understanding of the wide variation of technical requirements and considerations associated with these applications is critical to decision making about laser-scanning implementation on projects. Furthermore, significant industry transformations in the use of building information modeling present extraordinary opportunities for AEC professionals to employ the use of laser scanning in the context of holistic, collaborative workflows grounded in three-dimensional model-based design. This report analyzes the construction engineering requirements of laser scanning technology for applications across all phases of the project life cycle and proposes a multidisciplinary framework to integrate applications of laser scanning technology with the fundamentals of three-dimensional model-based design.     

Antecedents of Successful Three-Dimensional Computer-Aided Design Implementation in Design and Construction Networks

Researchers find that the successful implementation of information systems that span organizational boundaries enhances competitive advantage. However, the process by which networks of design and construction firms implement boundary-spanning technological changes remains poorly understood. In this paper I explore the implementation of three-dimensional computer-aided design tools in 26 design and construction organizations. I analyze empirical data collected over a 7-month period to induce a set of antecedent constructs that enable the evolution from “printed sets of plans” to “virtual model” boundary objects. The findings highlight the importance of addressing regulative, technological, work, and organizational issues at the interfaces between design and construction firms when implementing boundary-spanning technological changes.     

Web-Enabled System Dynamics Model for Error and Change Management on Concurrent Design and Construction Projects

Construction projects are uncertain and complex in nature often because of iterative cycles caused by errors and changes. These errors and changes impair project performance and, consequently, cause schedule and cost overruns to be prevalent. Iterative cycles are more detrimental when design and construction are concurrent and often force activities to proceed without complete information. In an effort to address this issue, this paper presents the information technology aspect of the dynamic planning and control methodology (DPM), which provides a mechanism that will analyze the impact of negative iterative cycles on construction performance. In order to guarantee a smooth application of this method to real-world projects, DPM has been developed by integrating several existing methods around a core system dynamic model for quality and change management and then implementing these methods into a web-based collaborative environment. A case project, applying the developed web-based DPM, shows great potential in facilitating on-site decision making by virtue of its support of data analysis as well as real-time information sharing.     

General-Purpose Situational Simulation Environment for Construction Education

The traditional construction education model based on precise well-defined problems and formal definitions is not satisfactorily fulfilling its mission of educating the decision makers of tomorrow. This realization has moved several researchers to explore alternatives where problem solving is carried out in conjunction with the environment, and concepts are embedded in the context promoting learning within the nexus of the activity. Several efforts have been undertaken to develop these environments resulting in a variety of special-purpose situational simulations. However, special-purpose situational simulations exhibit inherent limitations related to their application breadth, flexibility, and promotion of collaborations. These limitations cannot be resolved within the framework of special-purpose learning environments. A general-purpose environment is required to overcome these shortcomings and take full advantage of the situational learning paradigm. This paper describes the conceptual framework and pilot implementation of such an environment called the Virtual Coach.