Journal of Construction Engineering and Management

During planning and execution of construction projects, project planners and managers make various assumptions with respect to execution of construction activities, availability of resources, suitability of construction methods, and status of preceding activities. However, not all of these assumptions are explicitly documented and verified before the construction activities start. Decisions made based on invalid assumptions can negatively impact the outcomes of construction projects, such as rework, activity delays, and extra material cost. To address the problems caused by invalid assumptions, this paper proposed to develop a formal approach to capture and represent assumptions and proactively verify assumptions to reduce the uncertainties associated with construction projects. To develop such a formal approach, an initial step is to identify characteristics of assumptions. The research team conducted two detailed case studies (i.e., a bridge rehabilitation project and a research lab renovation project) and seven interviews with construction professionals who have experience between 12 and 50 years. This paper provides a detailed discussion on the assumptions identified from case studies and interviews. The developed categorization of assumptions and the general characteristics of assumptions can serve as the foundation for a formal representation of assumptions, which helps construction professionals to proactively verify assumptions so as to avoid negative impacts of invalid assumptions on construction planning and execution.

As a high-stress working environment, the construction industry affects the health and well-being of people who work in it. Knowing what factors contribute to or ameliorate workplace stress, and their interrelationships, are important. Data from 350 cases that reflect self-perceived stress experiences were collected via an online questionnaire survey of architects, civil engineers, quantity surveyors, and project and construction managers in South Africa. These data were used to conduct logistic regression modeling to explore the relationship between perceived stress at work, workplace demands, job control, and workplace support. The strength of the relationship of 13 factors with perceived stress was modeled. Although all the cataloged factors contribute to a predictive likelihood of high workplace stress, the strongest predictive factor is the perceived presence of work-life imbalance. The perceived need to work long hours is overwhelmingly mediated through imbalance experienced between work and life/family commitments. A perceived need to prove oneself at work also strongly mediates this relationship, whereas the extent of support received from colleagues in difficult situations may serve as a strong moderator. An amended model of occupational stress is proposed that distinguishes between mediating and moderating factors, providing possible target areas for organizations wishing to address employee stress issues. The contribution of this work lies in its examination of the work stress experienced by construction professionals in a developing country that is characterized by economic hardship and social problems.

This paper analyzes key issues facing subcontractors in the context of a severe economic crisis, aiming to detect the factors that are critical for the survival of the subcontractors. Although previous research efforts have analyzed factors related to subcontractor performance in regular financial conditions, there remains only sparse knowledge of how subcontractors are to survive when economic conditions become dire, as they have in recent times in the Spanish construction market. In this research, in-depth interviews with managers of relevant Spanish subcontracting companies were carried out, resulting in the identification of eight factors for subcontractor survival: project delivery method, demand, financial capital, relationship assets, managerial assets, human assets, legal framework, and geographic scope. The project delivery method used by the owner and also by the main contractor is mainly based on price. As a result, the subcontractors’ bids get lower, making them unsustainable in the long run. Furthermore, subcontractors do not get financial support from banks easily to cover their additional financial costs. These facts push subcontractors to get a guarantee of payment by the main contractor, and subcontracting companies may even ask for payments in advance. Subcontractors also seek long-term relationships with the contractor. These trusting relations are very often a prerequisite to qualify and bid for contracts. Subcontractors have to continuously improve, plan ahead, and adapt quickly to the new environment. Therefore, subcontractors must remain flexible and maintain a lean hierarchical organization. Doing so makes it is easier for subcontractors to compete in both their native markets as well as abroad. To this end, the most successful subcontractors have become international during the expansion phase of the economic cycle; many of them went abroad with the help of a contractor from their home country.

Exterior wall painting is one of the most widely-used coating solutions in Portugal. It is particularly susceptible to degradation; this affects the quality of public spaces and the image of cities. The study of service-life prediction contributes to a more rational management of the maintenance of buildings. The state of repair of 220 façades in the Lisbon region of Portugal determined through an in-service survey is analyzed. The model proposed to estimate the service life of painted surfaces is a relatively simple method that balances cost and speed, enabling its practical application to any structure. The models obtained enabled degradation patterns to be identified. The method yielded an average (reference) service life of paint coatings of around 10 years. A technoeconomic analysis was then performed that compared various maintenance strategies for a period of time of 20 years, as follows: (1) maintenance every 5 years, (2) maintenance at 15 and 20 years, and (3) maintenance adjusted in accordance with the findings of service-life prediction of painted surfaces. The research reported in this paper proved that technical knowledge can be converted into economic and performance gains. In this case the maintenance strategy based on service-life prediction data proved to be the best. Tools such as these are essential to the maintenance of built heritage.

Despite the significant benefits associated with building information modeling (BIM), the industry has not properly addressed a host of legal issues, risks, and barriers. Intellectual Property Rights (IPR) is of primary concern; therefore, this paper attempts to discuss IPR in the context of BIM application. It reviews the two issues of who a BIM’s copyright owner should be and how to avoid infringement of IPR raised by the previous literature and proposes solutions. Interviews were conducted with experts in Taiwan to discuss opinions on these two issues. Moreover, experts were also asked to comment on two new issues raised by this study: (1) possible ways in which professional knowledge relating to business can be protected; and (2) ways in which work on elements of BIM can be protected. Combining the results of literature reviews and interviews, this study concludes the issues of BIM application in IPR perspectives and suggests solutions. The importance of these issues and their proposed solutions is validated by a questionnaire distributed among various other experts, and the results are given. This paper not only summarizes the BIM’s IPR issues but also proposes practical solutions accordingly.

Many construction professionals experience high levels of stress. Workplace stress leads to psychological, physiological, and sociological strain effects. Sufferers adopt different coping mechanisms in attempts to mitigate their condition. Using an online survey, opinions were sought from architects, civil engineers, quantity surveyors, and project and construction managers in South Africa. The contribution of the research reported in this paper lies in its examination of the work stress experienced by construction professionals in a developing country characterized by economic hardship and social problems, such as inequality and crime. Most respondents experience high levels of stress at work. Architects (more than engineers, quantity surveyors, and project and construction managers) and female (more than male) professionals feel stressed. Psychological effects of workplace stress include the feeling of not being appreciated by others for a job well-done, feeling dissatisfied with one’s own performance at work, and feeling tense at work. Physiological effects include disturbances to usual sleep patterns, difficulty in relaxing after hours, and difficulty in concentrating. Sociological effects include a strain on family life, social activities, and social relationships. A wide range of positive coping mechanisms (or countermeasures) is reported, including physical exercise in addition to intellectual and cultural activities. From a negative-coping perspective, consumption of alcohol is widespread, with more than one-third of respondents consuming 3–9 units/week. One in six respondents report smoking of up to 40 cigarettes/day, whereas use of narcotics (such as marijuana, cocaine, mandrax, ecstasy, heroin, and methamphetamine) at least once in the previous 12 months is reported by 1 in 20. A duty-of-care ethos suggests that appropriate and carefully targeted stress-management strategies should be implemented by organizations within the construction industry. Further research is recommended to explore the effectiveness of organizational and personal stress-management interventions.

Each year, the United States invests $30 billion in federal construction. Military construction (MILCON) represents 40% ($12 billion) of that capital investment. This study confirmed the existence of MILCON cost premiums compared with private sector construction through an analysis of existing research. This study also evaluated two nearly identical projects and used expert interviews and surveys to determine which factors influence the cost premiums. The projects represented a rare opportunity to compare projects that had the same end requirement: method of execution and acquisition, design/build and firm-fixed price; and location but differed by government construction agent. In addition to identifying the 28 factors that moderately or largely influence cost premiums, five overarching cost-premium themes emerged: failing to balance risk, additional public-sector requirements, stifling or not applying innovation, selection of construction specifications, and parameterization of the execution process. Additionally, once complete, two nearly identical projects differed by over a year of construction time and $7 million in spite of the contract requirement similarities. Research frequently cites federal laws and policies as the primary cost-premium driver; however, this research demonstrated that internal construction agent policies also cause increased cost premiums. Mitigating the causes of internal cost premiums could improve public-sector construction cost performance.

Due to the dynamic nature of construction projects, multiple stakeholders with various expectations are often involved. To achieve consensus among different stakeholders, public engagement (PE) is increasingly adopted for mega development projects. However, it is really difficult to satisfy various stakeholder needs if PE is inappropriately conducted. PE has been criticized for its illogical and unsystematic processes underlying decisions. Hence, the current study aimed to explore and identify critical factors of the PE process in order to improve final performance. To achieve this aim, four focus groups were held involving different types of stakeholders (e.g., governmental departments, construction professionals, interest groups, and local residents). PE process factors, addressed in the focus groups, fell into two main categories: logical decision-making process and team behaviors, with the latter divided into task and personal dimensions. The results of the current study were used as the first stage of a comprehensive study aimed at improving PE performance. Several practical recommendations for facilitating the PE process were also pointed out in the group discussion, such as the application of logical and systematic decision-making processes, the establishment of effective evaluation methods and frameworks for evaluation criteria, and the usage of transparent and equal discussion rules.

Attempts to predict construction cost represent a problem of continual concern and interest to both practitioners and researchers. Such an attempt is presented here for the specific challenge of cost prediction when undertaking seismic retrofitting of existing structures. Using multilinear regression analysis, 14 independent variables were analyzed to develop parametric models for predicting the retrofit net construction cost (RNCC). Half of these variables have never previously been studied in the literature. The required data for this study were collected from 158 earthquake-prone public schools in Iran, each having a framed structure. The backward elimination (BE) regression technique was used to identify any variables that made a statistically significant contribution to the RNCC. The suitability of the BE technique for this identification was examined and demonstrated using a number of model-selection criteria. Rather surprisingly, building age and compliance with the earliest practiced seismic design code were found to be insignificant predictors of the RNCC. As reflected by the BE technique, the significant predictors were building total plan area, number of stories, structural type, seismicity, soil type, weight, and plan irregularity. The causal analysis performed between the RNCC and these variables showed that the first two variables have the greatest influence on the determination of the RNCC. The primary contribution to the construction industry is the introduction of a simple double-log cost-area model for predicting seismic retrofit construction cost. The introduced model enables engineering consultants, managers, and policy makers to simply predict this cost at the early planning and budgeting stage of seismic retrofit projects.

Cost contingency is one component of a project’s budget to cater for cost growth. The determination of a project’s cost contingency is a pervasive problem because the amount that is incorporated into an estimate is invariably insufficient to accommodate the cost growth of a project. This study analyzed the statistical characteristics of cost contingency and cost growth experienced in 228 similar Australian water infrastructure projects that were procured by using traditional lump contracts. It was revealed that mean project final costs exceeded the approved budgets that contained contingency. The mean contingency percentage addition was 8.46%, yet the mean contingency required for the final cost was 13.58% for the sampled projects. Thus, the deterministic percentage addition, used by the sponsor to accommodate for cost growth beyond their baseline budget, was inaccurate. To improve the accuracy of a contingency estimate, the empirical distributions of cost contingency and cost performance were examined to determine their best-fit probability distribution. The research presented in this paper demonstrates that determining the best fit probability distribution provides a more robust and defendable basis for selecting a cost contingency than the traditional deterministic percentage approach.

The ability to predict and develop policies, programs, and environments that enhance work-life balance (WLB) and promote organizational commitment is important for employers concerned with minimizing employee turnover. The aim of this study is to investigate elements that lead to enhanced organizational commitment and increase the likelihood that a female employee will stay with her employer in the U.S. construction industry. The specific contributions of this study are that it ascertains through a survey questionnaire the relative importance of different aspects of employer, job, employee benefits, and personal life satisfaction elements. The factor with the most pronounced influence on satisfaction with employer was whether the respondent had earned a college degree or trade certificate. Respondents with a college degree or a trade certification were more than four and a half times more likely to respond as satisfied with their current employer than those who did not have a degree or certification. Having children in the household also was a predictor of short-term (6-month) employee commitment, but not for long-term (5-year) commitment. Instead, marriage or an intimate relationship and retirement benefits were predictors of long-term commitment. Predictive mathematical models for these elements were developed, tested, and validated. These models allow employers to measure the employee’s satisfaction with the employer, and the short-term and long-term employee commitment among their U.S. female construction industry employees. The results can be used by employers to develop intervention strategies to enhance WLB, promote organizational commitment, and minimize female employee turnover.

This paper presents the development of prediction models for the unit costs of road works that could be applied to strategic planning of road works at the network level. A specialized data set was used, which was generated under a World Bank study that included 200 road work contracts from 14 countries in Europe and Central Asia (ECA) and signed between 2000 and 2010. Two techniques were used for model development: multiple regression analysis and artificial neural networks. Classification trees were used as an intermediate step to evaluate the correctness of the selected parameters. A total of 19 variables, divided into three groups (oil-price related, country-related, and project-related variables), were tested for their influence on unit cost of asphalt concrete (AC) and road rehabilitation and reconstruction (RRR) costs. The analysis results showed that the level of corruption and the economic environment in a country have a significant effect on both costs of AC and RRR. The resulting models could be particularly useful for the planning and optimization of work on road networks in ECA countries. However, the approach and methodology used for model developments may be applied generally.

Subcontractors have a significant role in the construction industry. Through involvement at different levels, subcontractors may undertake up to 90% of the total value of large construction projects. Due to the lack of systematic relationships and communication among different parties involved in construction projects, many beneficial opportunities such as short-term partnering may stay hidden and unknown during the course of projects. Although partnering is well documented in the literature, quantitative approaches have not been common for determining the value of partnering and developing practical methods for allocation of its benefits. In this study, we discuss how subcontractors can benefit considerably from joint resource management in construction projects. We present a short-term partnering case in which subcontractors form an alliance, agreeing to put all or some of their resources in a joint pool for a fixed duration of time and to allocate the group resources using a more cost-effective plan. Cooperative game theory is suggested as the basis for fair and efficient allocation of the incremental benefits of cooperation among the cooperating subcontractors. First, a resource-leveling model is used to build subcontractors’ characteristic functions for all possible subcontractors’ coalitions. Then, various cooperative game theoretic solution methods are applied for allocation of cooperative gains among the subcontractors. Finally, to ensure that the identified allocation rules are applicable and stable in practice, acceptable allocations are identified using various stability analysis methods. Results show that considerable savings can result from full cooperation among subcontractors based on group rationality as opposed to individual rationality.

Topography and physical characteristics of a project should be considered in the preconstruction planning for any construction site. However, many of the technologies used for generating digital models of site topography rely extensively on project site surveys. This paper contributes to the body of knowledge by improving the understanding of the nature and sources of remotely sensed data for construction applications as well as the accuracy of digital terrain models (DTMs) derived from remotely sensed data. Airborne light detection and ranging (LiDAR), satellite imagery, and models provided by the USGS are three different sources of remotely sensed data that have been used in this study. It is expected that the research outcome will overcome some of the drawbacks of the existing methods for modeling site topography. The elevation values derived from these terrain models are compared with the values that have been measured in the field. The results indicate that the LiDAR-based DTM represents the best vertical accuracy in comparison to satellite-image-based and USGS DTMs.

The need to maintain an ever-increasing building stock especially in developed economies is growing. This study provides a computational framework to find the optimal solution for sustainable building maintenance. The methodology is composed of two major steps. First, the authors evaluate the life-cycle carbon emission, cost, and labor requirements of a project, which embody important environmental, economic, and social aspects of sustainable building maintenance. Second, the authors develop an optimization model to identify the optimal portfolio of materials that would minimize three sustainability objectives including carbon emission, cost, and labor deployment in their respective turns one at a time. By testing the model with seven scenarios in a case study, the authors demonstrate how this typical case project could significantly improve its sustainability objectives from environmental, economic, and social perspectives. This optimization methodology is generic. It can be readily applied to other new and nonresidential projects of varying scales and in circumstances with a different set of decision criteria. Finally, policy suggestions are proposed to promote sustainable building maintenance in Hong Kong.