Journal of Construction Engineering and Management

In addition to materials, labor, equipment, and method, construction cost depends on many other factors such as the project locality, type, construction duration, scheduling, and the extent of use of recycled materials. Further, the fluctuation of economic variables and indexes (EV&Is), such as liquidity, wholesale price index, and building services index, causes variation in costs. These changes may increase or reduce the construction cost, are hard to predict, and are normally ignored in the traditional cost estimation computation. This paper presents an innovative construction cost estimation model using advanced machine-learning concepts and taking into account the EV&Is. A data structure is proposed that incorporates a set of physical and financial (P&F) variables of the real estate units as well as a set of EV&Is variables affecting the construction costs. The model includes an unsupervised deep Boltzmann machine (DBM) learning approach along with a softmax layer (DBM-SoftMax), and a three-layer back-propagation neural network (BPNN) or another regression model, support vector machine (SVM). The role of DBM-SoftMax is to extract relevant features from the input data. The role of the BPNN or SVM is to turn the trained unsupervised DBM into a supervised regression network. This combination improves the effectiveness and accuracy of both conventional BPNN and SVM. A sensitivity analysis was performed within the algorithm in order to achieve the best results taking into account the impact of the EV&I factors in different times (time lags). The model was verified using the construction cost data for 372 low- and midrise buildings in the range of three to nine stories. Cost estimation errors of the proposed model were much less than those of both the BPNN-only and SVM-only models, thus demonstrating the effectiveness of the strategies employed in this research and the superiority of the proposed model.

There is no doubt that US construction safety records have been improving over the years, yet hundreds of deaths occur annually as a result of jobsite incidents. This continuing injury trend requires further understanding of the causes of safety issues as well as what magnifies safety risk. This study aims to investigate the extent of the impact of different factors on worker safety risk. The factors, namely human, site conditions, psychological, environmental, social, economic, regulatory, ergonomic, and organizational, were developed as part of recently formulated degrees of connectivity (DoC) model scenarios utilizing the risk perception of different specialists. The risk perceptions associated with the factors as provided by construction safety university professors and practicing safety engineers are explored for comparison. The Delphi method was adopted to collect the required data from both mentioned groups. The results show that the participants perceive that site condition factors create the highest impact whereas the worker economic factor adds the lowest impact. No significant difference was observed between the two groups in terms of risk perception, nor was there a clear impact of participant experience on the risk perception process and the factors under investigation. Safety planners can benefit from the study results by considering the level of impact that the factors have on worker safety. Moreover, when addressing safety on a project, both professors and engineers can contribute equally.

Temporary structures are designed from complex structural analyses. Concrete formwork is a representative temporary structure, and frequently fails during construction due to unexpected external factors. Therefore, safety managers should constantly monitor structural behavior to determine whether the formwork is performing safely. Information on structural behavior provides knowledge on the characteristics of actual temporary structures and can help ensure safe concrete placement. The objective of this study is to present a guideline for safe concrete placement based on an understanding of the structural behavior of concrete formwork. Using ubiquitous sensor network devices, an indoor test bed was built to test the structural behavior of concrete formwork. Eight scenarios were investigated, representing typical safety conditions that occur for concrete formwork. Finite-element analysis was conducted for these scenarios to provide a guideline for safe concrete placement. Laboratory loading tests conducted on the test bed validated that the safety guideline provided a suitable procedure to cope with abnormal behaviors on concrete formwork and can be applied to ensure safe concrete placement.

A contractor’s continued financial health throughout a construction project is a basic requirement for successful project completion. Therefore, project owners must be conversant with the contractor’s financial capability from the bidding stage through project completion. Consequently, project owners adopt a prequalification (PQ) process to screen for poor technical and managerial capabilities during the bidding stage. Although the PQ pass rate in Korea is nearly 99%, contractor liquidity can still pose problems. In this situation, the most important construction management strategy involves monitoring the contractor’s liquidity status during the project. Accordingly, this study determines the symptoms of contractor decline at the corporate and project levels. Nineteen variables (17 financial and two nonfinancial) are selected through a symptom analysis. Moreover, this study develops a liquidity evaluation model (LEM) and its reference mode based on equations obtained by performing multiple discriminate analyses. These results demonstrate the practical feasibility of project owners to evaluate contractor liquidity using financial and nonfinancial information to prepare for possible financial problems.

The focus of this paper is on the relatively under explored area of partially completed (part-built) information modeling because this can assist during on-site construction processes. Additionally, incremental models will support the as-built model through demonstration of hidden construction in the finished building. This is achieved by evaluating state-of-the-art scanner technologies to determine relative performance and accuracy in creating part-built models. Five laser-based scenarios using state-of-the-art handheld and terrestrial scanners were deployed to examine their capability to accurately produce part-built modeling from constructed objects. It was found that terrestrial scanners provided more accurate part-built information models, although the operation process is technical and requires skilled operators. However, handheld instruments avoid individual setup points and take less time than a terrestrial station when scanning typical internal building floor areas. This study contributes to the body of knowledge by developing the concept of part-built information modeling using scanner technology, as well as by creating related evaluation criteria.

Adequate assessment of risk is essential to assist the stakeholders in planning for efficient risk allocation and mitigation and to ensure success in business and projects. However, it is problematic due to the difficulty in quantification of certain risks, existence of interactions, and multiattribute structure of the project risk assessment task. This paper reports research in which relevant risks were identified for power and transport infrastructure public-private partnership (PPP) projects, which are globally the most active infrastructure sectors for private investment. It further proposes, demonstrates, and validates a novel multiattribute risk assessment model that supports both sectoral and project risk analysis to assist stakeholders in risk management decision making. A 45-factor risk register, established based on literature review and PPP experts’ interviews, was administered to solicit industry-wide perceptions for risk assessment. Application of fuzzy set theory to risk analysis revealed 22 critical risk factors (CRFs) that were categorized into seven critical risk groups (CRGs) of correlated factors using factor analysis. Risk factors that achieved a linguistic assessment of high impact reflect issues related to institutional capacity and the local economy. Further analysis based on fuzzy measure and nonadditive fuzzy integral combined with arithmetic mean helped to obtain an overall risk index (ORI) which indicated a moderate risk outlook for both power and transport infrastructure sectors. Whereas public sector maturity was assessed as a high impact CRG in the power sector, project planning and implementation, project finance, and project revenue were additionally rated as high impact CRGs in the transport infrastructure sector. Demonstration of the developed methodology for a build-operate-transfer (BOT) motorway case study project showed that the private sector stakeholders viewed the project at high risk with all the CRGs evaluated as high impact except the political stability CRG, which was assessed as moderately risky. Test results show that the methodology performed satisfactorily in approximating experts holistic project risk assessments. The developed framework can be used to assess a country’s condition or overall project risk at the initial project stage with little input of time and resources, thus facilitating an efficient and robust risk assessment. Application of fuzzy measure based nonadditive fuzzy integral combined with arithmetic mean for sectoral and project risk assessment, and comparison of sectoral risk analysis from a developing country perspective are some of the key features of this study.

Construction project environments are shaped by uncertainty and complexity; therefore, conflict situations that lead to time and cost overruns are rather frequent. However, no empirical studies conducted so far have analyzed conflict management performances of individuals on a context-dependent basis. This paper proposes a performance assessment methodology for conflict management that integrates two different approaches from other disciplines: hypothetical situations and competency theory. The approach analyzes managers’ performances in the exact same conflict cases through an after-scenario questionnaire based on their preferences toward candidate management scenarios, each of which reflects one of the required competencies for effective conflict management. Considering the context-dependent characteristics of the conflict phenomenon, the implementation of the methodology within this paper’s context is confined to the construction industry. The methodology was implemented among 82 construction project managers through an after-scenario questionnaire, and three random participants’ conflict management performances were analyzed. Based on a novel construction conflict management performance assessment methodology, this research can offer two contributions to the body of construction conflict management knowledge. First, it has revealed the lack of a generic hierarchy in terms of the competencies required. Second, the results confirmed that construction managers’ conflict management performances may vary despite identical years of experience and managerial positions held.

Public–private partnerships (PPP) have been widely applied in infrastructure projects in developing countries. However, many projects have been abandoned or canceled owing to an insufficient understanding of risk factors, lack of awareness of the financial consequences of risk, and a limited understanding of risk bearers’ capacity to handle risks. Using a mixed research method, this study identified critical risks in PPP toll road projects in Vietnam that affect the projects’ financial viability, determined the PPP partners capable of managing these risks, and explored the causes to these risks and their management strategies. Empirical data collected from quantitative and qualitative studies revealed 22 risks critically affecting toll road projects’ financial viability in Vietnam, either by inflating projects’ cash outflows or reducing projects’ cash inflows in a commonly used net present value (NPV) analysis model. This confirms the important role of government support and guarantees in the mitigation of the risks in developing countries and indicates that governments need to actively get involved in managing these risks and planning for the associated government support. This study provides a comprehensive understanding of risk management in PPP toll road projects in Vietnam, which will not only benefit public management, policy consultants, and investors, but also academics interested in studying PPP projects in developing countries.

Work item production rates are essential for contract time determination (CTD) procedures as they are used to estimate the duration of activities needed to complete a highway construction project. For this reason, varied sources and estimation systems provide production-rate data for a variety of work items. Yet these data sources are disjointed and do not provide for any side-by-side comparison of data. This research focuses on the development of an integrated Production Rate Resource, a single, easy-to-use reference of production-rate data gathered from publicly available sources. The resource was developed by gathering production-rate information from multiple sources and organizing the found data into a well-assembled Excel workbook. A proposed process for conducting CTD using the resource is included. The gathered information was tested by estimating the contract time of highway projects using the recommended process. Findings from the application led to significant improvements to the resource. The final version of the Production Rate Resource provides integrated production-rate data for 59 highway construction work items and a recommended process for conducting contract time estimation.

To widen the applications of large-diameter prestressed high-strength concrete (PHC) piles to stiff strata, this paper introduces a novel hybrid piling technique, including the equipment and construction procedures. The spiral drilling operation provides space for simultaneously lowering the piles, and the detected real-time parameters characterizing the construction status can be also automatically transferred to additional exciting force or constraints acting on the piles by a sophisticated feedback loop. The application of the proposed technique is verified with two large-diameter test piles installed into stiff weathered granite. It is experimentally demonstrated that, taking advantage of the unique grouted gap between the piles and the bored hole, the pile–strata adhesive strength and therefore the shaft resistance of the pile are significantly enhanced. Comparison of the tested piles shows that the trade-off relation between the grout quality and the modulus reduction of the strata plays an important role in controlling the bearing performance of the piles because the shaft resistance does not always increase with the modulus of the surrounding strata if the strength of the grouted interface is relatively small. The findings can provide fundamental guidance for further optimization of the proposed technique from the aspects of both design and construction.