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Copyright of Journal of Engineering Management / Gongcheng Guanli Xuebao is the property of Journal of Engineering Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The use of Monte Carlo simulation in construction cost analysis is of interest to construction professionals as part of the risk analysis of construction projects. In recent high profile publications the presentation of Monte Carlo simulation based cost analysis overplays the importance of the choice of which distribution to use to represent input variables and underplays the importance of assessing and including correlations between the variables. The British literature also overplays the suitability of the beta distribution to represent input variables. This paper addresses these issues using a data set comprising elemental rates from 216 office buildings drawn from the BCIS of the RICS. Using a chi-squared test for goodness of fit it is shown that lognormal distributions are superior to beta distributions in representing the data set. Simulation runs of the cost model including and excluding correlations show that correlations must be included in Monte Carlo simulation otherwise the analysis leads to serious misassessment of risk. Simulation results show also that the effect of excluding correlations is more profound than the effect of the choice between lognormal and beta distributions. [ABSTRACT FROM AUTHOR]

This note supplements papers by Chau in an attempt to further the consideration of risk measures in forecasts of construction project costs. The note reviews the application of PERT-based aspects of analysis and simple portfolio theory. Consideration is given to subjective factors in cost forecasting which arise from the natures and experiences of the forecasters as well as pressures to which they (may) feel subjected. Alternative measures of risk exposure are examined and supplementary analyses of the data contained in Chau's paper are reported. Although the log-triangular distribution is confirmed as a superior means of measuring risk, the observed risk measures still exceed those calculated [ABSTRACT FROM AUTHOR]

Construction process activities are very complex in nature and there have been attempts to simulate them via numerous methods. Manual work, which constitutes a large proportion of total construction in India and developing countries, requires emphasis. Field data-based mathematical simulations develop an empirical relation between inputs and outputs; once the model is developed and weaknesses have been identified, methods can be easily improved and optimised for output goals. This paper covers in detail the process of developing models for the rebar cutting subactivity of reinforced concrete construction in residential buildings. These models are evaluated using sensitivity analysis, optimisation techniques and reliability analysis and are validated using artificial neural networks. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Managing heavy-pressure vessel lifts on construction sites requires planning, arranging adequate crane support, and preparing collision-free rotation (from a horizontal position to a vertical position) of the vessel. Generally, selecting mobile cranes and developing engineered lift studies for vessels are done using two cranes and analyzing the lift for each crane individually on the basis of the selected cranes' lift-capacity specifications provided by crane manufactures. This practice is relatively costly and time-consuming. Optimizing the mobile cranes' use and location is also difficult. To assist in the field operation of mobile cranes and to provide engineers with a planning tool, this paper presents a methodology to carry out such a lift utilizing only one crane. Using the developed methodology and mechanism, heavy vessels can be rotated off the ground (in the air) with one crane. The proposed mechanism is supported with a mathematical model that has been developed into a computer system and has been integrated with a previously developed crane selection and ground pressure calculation system and crane database. The developed system provides users with a lift study analysis for a given configuration as well as simulation results with interactive graphics to assist in the selection of an optimum configuration. This research is important as projects involving heavy lifts need to reduce the cost and time associated with construction operations. [ABSTRACT FROM AUTHOR]

The importance of integrating construction knowledge into the design process has long been recognized by the construction industry. This paper studies early contractor involvement in design and its impact on construction schedule performance through a combined empirical case study and theoretical simulation analysis. Pipe and steel fabricators’ inputs at different design stages of industrial construction projects are identified. The case study shows that these inputs lead to improved drawing quality, material supply, information flow, and consequently improved construction schedule performance. This impact on construction schedule is illustrated using actual project data and simulation techniques. Simulation models were developed to demonstrate intuitively the impact at the construction operation level and they allow people to gain management insights through simulation experiments. Better understanding of the early contractor involvement process and its benefit can improve buy-in and help industry practitioners to reach the full potential of this concept. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: The paper gives an overview of heating, ventilation and air-conditioning (HVAC) system modeling and simulation. The categorization of tools for HVAC system design and analysis with respect to which problems they are meant to deal with is introduced. Each categorization is explained and example tools are given. Further, the paper summarizes current approaches used for modeling (i) HVAC components, (ii) HVAC control and (iii) HVAC systems in general. After giving an overview of solution techniques for HVAC system simulation, the paper provides suggestions on how one should select an HVAC modeling approach relative to the simulation objective at hand. [Copyright &y& Elsevier]

A significant number of large-scale civil infrastructure projects experience cost overruns and schedule delays. To minimize these disastrous consequences, management actions need to be carefully examined at both the strategic and operational levels, as their effectiveness is mainly dependent on how well strategic perspectives and operational details of a project are balanced. However, current construction project management approaches have treated the strategic and operational issues separately, and consequently introduced a potential conflict between strategic and operational analyses. To address this issue, a hybrid simulation model is presented in this paper. This hybrid model combines system dynamics and discrete event simulation which have mainly been utilized to analyze the strategic and operational issues in isolation, respectively. As an application example, a nontypical repetitive earthmoving process is selected and simulated. The simulation results demonstrate that a systematic integration of strategic perspective and operational details is helpful to enhance the process performance by enabling construction managers to identify potential process improvement areas that traditional approaches may miss. Based on the simulation results, it is concluded that the proposed hybrid simulation model has great potential to support both the strategic and operational aspects of construction project management and to ultimately help increase project performance. [ABSTRACT FROM AUTHOR]

Abstract: To date, few construction methods or models in the literature have discussed about helping the project managers decide the near-optimum distributions of manpower, material, equipment and space according to their project objectives and project constraints. Thus, the traditional scheduling methods or models often result in a “seat-of-the-pants” style of management, rather than decision making based on an analysis of real data. This paper presents an intelligent scheduling system (ISS) that can help the project managers to find the near-optimum schedule plan according to their project objectives and project constraints. ISS uses simulation techniques to distribute resources and assign different levels of priorities to different activities in each simulation cycle to find the near-optimal solution. ISS considers and integrates most of the important construction factors (schedule, cost, space, manpower, equipment and material) simultaneously in a unified environment, which makes the resulting schedule that will be closer to optimal. Furthermore, ISS allows for what-if analyses of possible scenarios, and schedule adjustments based on unforeseen conditions (change orders, late material delivery, etc.). Finally, two sample applications and one real-world construction project are utilized to illustrate and compare the effectiveness of ISS with two widely used software packages, Primavera Project Planner and Microsoft Project. [Copyright &y& Elsevier]

Purpose – Modelling construction resources and their dynamic interactions and constraints are a challenging problem. The allocation of these resources to competing activities is usually a function required in any scheduling process. Performing such allocation under a dynamic and diverse set of constraints adds more complexity to the problem. This study seeks a structured approach for representing resources and their allocation to different activities through the use of an agent-oriented modelling framework. Design/methodology/approach – A model is developed for a real case of assembly operations of industrial construction modules. The model follows a multi-agent resource allocation structure and is implemented within an agent-based simulation environment. The model is used to evaluate the effects of different optimization algorithms and modelling parameters on the generation of a construction schedule. Different experiments run through the model and their results are analyzed and discussed. Findings – The model showed sensitivity only under large and continuous workloads. Overall the structured approach followed in developing the model provided a flexible medium for experimenting with different elements of the resource allocation problem. Research limitations/implications – The work is limited to the studied case and the results cannot be generalized beyond similar cases. The modelling approach used in the study provides a platform that can facilitate future research in construction resource allocation strategies. Originality/value – The presented work demonstrates a new approach for modelling construction resource allocation problems that enables structured experimentation with alternative allocation algorithms. It also presents a novel way for modelling modular industrial construction operations. [ABSTRACT FROM AUTHOR]

Presents a method to determine a beta probability distribution function (PDF) for use in construction simulation modeling. Subjective determination of probability distribution functions; Family of beta probability distribution functions for construction applications; Estimation of beta PDF parameters; Application of methodology for subjectively deriving beta PDF.

Discusses the use of n dimensional (nD) modeling in the field of information communication technologies in construction. Origin of nD in building information model and object-oriented computer-aided design; Limitation of the industry foundation classes, an international data modeling standardization; Key features of nD.