Publications

Concurrent Construction Scheduling Simulation Algorithm

Abstract A scheduler can accelerate a construction project by setting up overlapping activities. Activities are said to be overlapping if two activities that are normally executed in sequence are performed in parallel, the successor starting before the end of the predecessor. This article presents a novel method that identifies an optimal overlap rate between critical activities to provide a time‐cost trade‐off analysis, hence reducing completion time and cost without allocating additional resources. This method is then coded into Concurrent Construction Scheduling Simulation System (C 2 S 2 ) that makes use of schedule data exported from Primavera Project Planner (P6), integrates the activities’ concurrency attributes, calculates the rework probability/amount, and computes the variability in project completion time and cost by adjusting the overlap between activities. This study is of value to practitioners because C 2 S 2 allows establishing a compressed schedule that satisfies a limited budget within a specified contract duration. The study is also of relevance to researchers because it identifies the optimal overlaps between activities expeditiously. Two test cases verify the usability and validity of the computational methods implemented in the system.

Energy and atmosphere standards for sustainable design and construction in different countries

Innovation in Construction Equipment and Its Flow into the Construction Industry

The rate of innovation in construction equipment is measured by using two variables over a 30-year period, 1962–92: The number of new models introduced every year and the technological life of eight earthmoving equipments are considered in this study. The findings indicate that the rate of innovation in the construction equipment industry increased in the 30-year study period. The findings also suggest that these innovations are incremental in nature, stimulated by technological advances in other industries, but primarily driven by market forces. Technological advances are not confined to the industry that produces innovations. The mapping of the interindustry flow of innovations highlights that while construction companies play a predominant role in generating their own technological innovations, they are also heavily dependent on other industries, such as the construction equipment industry for the flow of technical system innovations. As such, the continuous and incremental innovations in the construction equipment industry are bound to act as a catalyst for the generation of technological advances in the construction industry.

Subcontractor Selection for a Construction Project: Optimal Plan

An advanced decision-support system for ranking unbalanced bids

Awarding a contract to a bidder who has unbalanced the bid may cost more money to the owner. An owner who determines that a bid has been unbalanced has the legal right to reject the bid. Although several models have been developed to detect unbalanced bids, some researchers still assert that the number of cases in which owners mistakenly identify balanced bids as unbalanced is too great to ignore. One of the reasons of this failure is the use of an inappropriate benchmark against which the offered unit prices are compared. In this paper it is argued that the use of the geometric mean of the unit prices provided by the bidders as a benchmark helps to obtain robust solutions and an advanced decision-making model is proposed in which the Information Entropy and VIKOR methods are used to detect unbalanced bids. The results obtained from an example project drawn from the literature demonstrate how owners may be misled if they use an inappropriate benchmark in detecting unbalanced bids. This study contributes to the body of knowledge by highlighting the negative impacts of using flawed benchmarks in this process, an area of research that is mostly ignored in the unbalanced bidding literature.

Trends in Expectations about Duties and Responsibilities of Construction Managers

This paper discusses the findings of a study conducted under the direction and supervision of the ASCE Committee on Management Practices in Construction (MPIC) to investigate the expectations of the parties involved in the construction process including designers, general contractors, subcontractors, owners, construction managers (CMs), and educators, relative to construction managers' duties and responsibilities. Statistical analysis was conducted to investigate if consensus exists among the parties and to highlight the agreements and disagreements between them. The findings were compared against the findings of an identical study also commissioned by MPIC 10 years before this study was performed. This study raises awareness among project participants about the fact that they should reconcile their differences and have a common understanding of CM duties over all phases of the construction project since general agreement over CM duties makes CM scope negotiations all the easier.

Cost overruns in public projects

Optimum Finance-Based Scheduling

Graduate education in construction management

Construction management has been in existence for many years. This paper reviews the graduate construction management programmes offered by departments of civil engineering in the US. The courses offered in such programmes are categorized and examined in twelve groups. The findings indicate that the most popular subjects are those related to laws, contracts, and specifications; planning and scheduling; and operations research methods. Also, it was found that programmes differed a great deal from each other in terms of the concentration of and emphasis on the subjects treated. It is concluded that a clearer conception of the disciplineis necessary both by educators and the industry for higher quality and more uniform graduate programmes in construction management.

Assessing Coordination Performance Based on Centrality in an E-mail Communication Network

Building design and construction require the collective effort of diverse project participants. The coordination performance of these project participants is important for effective management and needs to be assessed periodically. However, there is no uncomplicated quantitative way to measure coordination. Measuring coordination is cumbersome and time-consuming particularly during the project execution phase. This study proposes an easy procedure for monitoring the coordinative performance of project participants. The degree, betweenness, and closeness centrality measures of the project participants in a wayfinding signage project at a major airport construction project are calculated using social network analysis on the e-mail communication network between the participants. A centrality index is defined for each firm based on the average of these three centrality measures. The firm's coordination score is also calculated based on content analysis of the sent and received e-mails between the participants. The coordination scores are found to be highly correlated with the centrality indices. To define the coordinative role of a firm, its centrality index could therefore be measured easily using a simple software and only the number and direction of e-mails exchanged between

Graduate Education in Construction Management

Construction management has become a vital aspect of the construction process over the years. This paper reviews the Master's programs in construction engineering and management (CEM) offered by departments of civil engineering in the United States. The findings indicate that only 20% of the American educational institutions, which offer accredited civil engineering programs, offer Master's programs in CEM. Most of the Master's programs in CEM constitute an effort to convey information to students on mainly six categories, namely, contract administration, project management, scheduling, equipment management, construction technology, and CEM research. It seems that the Master's programs in CEM do not differ much from program to program in terms of content. When the trends in course offerings are compared in 1982, 1996, and 2008, there seems to be minimal change except for the number of courses in project management that went up significantly while the number of courses in cost estimating went down. The trends in the remaining courses have been stable. Even though contents and trends in CEM programs appear to be relatively stable, there seems to be some variability in the concentration of the course offerings. Some CEM programs concentrate on some of the categories at the expense of other categories. A close relationship and a sound dialogue between construction educators and the industry are likely to lead to Master's programs that are in sync with the expectations of the industry.

Overview of Multi-Objective Optimization Approaches in Construction Project Management

The difficulties that are met in construction projects include budget issues, contractual time constraints, complying with sustainability rating systems, meeting local building codes, and achieving the desired quality level, to name but a few. Construction researchers have proposed and construction practitioners have used optimization strategies to meet various objectives over the years. They started out by optimizing one objective at a time (e.g., minimizing construction cost) while disregarding others. Because the objectives of construction projects often conflict with each other, single-objective optimization does not offer practical solutions as optimizing one objective would often adversely affect the other objectives that are not being optimized. They then experimented with multi-objective optimization. The many multi-objective optimization approaches that they used have their own advantages and drawbacks when used in some scenarios with different sets of objectives. In this chapter, a review is presented of 16 multi-objective optimization approaches used in 55 research studies performed in the construction industry and that were published in the period 2012–2016. The discussion highlights the strengths and weaknesses of these approaches when used in different scenarios.

Evaluation of LEED Requirements for Site Properties in Developing Country-Specific Certification

Construction activities are strongly affected by the properties of the site. Site conditions direct the investment decision and development approach. Leadership in Energy and Environmental Design (LEED), the most widely used certification system around the world, covers site properties with two sections, i.e., Location and Transportation, and Sustainable Sites. These two sections in LEED v4 NC add up to 42 points, which corresponds to approximately 33.3% of the total points that a building can receive. Issues such as neighborhood development location, sensitive land protection, high priority site, surrounding density and diverse uses, access to quality transit, bicycle facilities, reduced parking footprint, and green vehicles that are treated in the Location and Transportation section have different priorities and implications in developing countries. Similarly, issues such as pollution prevention, site assessment, site development - protect or restore habitat, open space, rainwater management, heat island reduction, and light pollution reduction that are treated in the Sustainable Sites section are based largely on local practices and standards, and therefore offer different challenges. In this study, these two sections of LEED v4 NC are assessed relative to practices in developing countries. A comparative review of the topics is performed by means of a thorough literature survey. It is expected that the outcome of the study will provide guidance to professionals in selected developing countries towards improvement of the existing state and practices.

Evaluating the Quality Performance of Pavement Contractors

This paper introduces a contractor quality performance (CQP) evaluation model that measures the quality performance of pavement contractors. The model uses a modified quality function deployment model to support the quality performance measurement that is involved in multiattribute and multiparticipant decision-making and the Delphi method to deal efficiently with the uncertainties in the input data. State DOTs that are in the process of selecting a pavement contractor for a project would benefit from the CQP evaluation model because the system allows a client to expeditiously assess the quality performance of potential pavement contractors in their bidding list. A test case is presented to illustrate the functioning of the model. The model contributes to improve the quality of the nation's pavements because it enhances the contract administration procedures by reengineering the current contractor assessment, prequalification, and/or selection process within the owner organizations (state departments of transportation) by accentuating total client (both the road users' and the owners') satisfaction. The model helps to improve the state DOT's pavement project bidding system.

Integrated Simulation System for Construction Operation and Project Scheduling

Simulation modeling is important in predicting the productivity of construction operations and the performance of project schedules. It would be desirable if operation and project models are vertically integrated in practice. However, existing discrete event simulation systems do not allow integrating operation and project models. This paper introduces an integrated simulation system named "Construction Operation and Project Scheduling" (COPS). COPS analyzes the productivity of construction operations as well as the performance of a project schedule individually and jointly. It creates operation models, maintains these models in its operation model library, conducts sensitivity analysis with different resource combinations, finds the optimal resource combination that satisfies the user's requirements relative to hourly production and hourly cost of the operation, feeds this information into a project schedule, and executes stochastic simulation-based scheduling. A case study is presented to demonstrate this integrated simulation system.

Exploring the Barriers against Using Cryptocurrencies in Managing Construction Supply Chain Processes

Various stakeholders are involved in managing supply chain processes in construction. Suppliers can hardly tolerate upfront costs when faced with flaws in the payment pipeline. This is a serious problem in building construction that uses a large variety of materials as opposed to civil construction that requires fewer types of materials. Alternative secure payment systems are needed, and the use of cryptocurrencies can be an option. However, cryptocurrencies are seldom used in building construction projects due to several challenges that are mostly ignored in the existing literature. To fill this gap, this study investigates the use of cryptocurrencies in construction supply chains as an alternative payment solution to improve the financial performance of the stakeholders by taking advantage of this economical and traceable financial transaction system. The study involves exploratory, descriptive, and empirical survey research. Accordingly, a literature review, focus group discussions, and statistical analyses (Friedman test, Wilcoxon test, and Mann–Whitney U test) were performed. The results imply that a lack of technical knowledge about cryptocurrencies, fluctuations in the value of cryptocurrencies, limited market opportunities, security gaps, personal information required by cryptocurrency systems, no assurance of permanent use, and government actions limiting the use of cryptocurrencies were the most significant barriers against using cryptocurrencies in construction supply chain management. The findings are expected to provide critical information to construction professionals and regulatory agencies about the potential advantages and shortcomings of cryptocurrencies, hence motivating policymakers to create strategies that minimize the concerns of construction professionals about using cryptocurrencies in the building construction industry.

Software needs for construction planning and scheduling