Journal of Construction Engineering and Management

Quality control/quality assurance tests can be used to demonstrate that an as-constructed pavement has characteristics different from the contracted specifications of the as-designed pavement because the bitumen employed was of insufficient quality. Many different issues affect asphalt binder quality. Such problems can significantly increase the pavement life-cycle cost, which means that a pay adjustment (PA) is needed. Unfortunately, the quantitative analysis of this issue is very complex. The objectives of this study were to model the dependence of the pavement life-cycle cost on asphalt binder quality and to determine the quantitative relationship between bitumen viscosity and the PA for a given class of boundary conditions. In addition to modeling this problem theoretically, experiments and simulations were carried out through the use of the Mechanistic-Empirical Pavement Design Guide. We then derived the consequences of these effects on life-cycle cost by using a specific life-cycle cost model. Our results demonstrate that asphalt binder viscosity can strongly affect the expected pavement life and the PA, and thus needs to be taken into account in contract and construction management.

Percent within limits (PWL) is a commonly used quality control/quality assurance measure of highway pavement materials and construction, and it is a popular index for adjusting pay factors. However, PWL is based on the assumption of normal distribution of quality characteristics (e.g., concrete compressive strength and asphalt air voids). Skewness and kurtosis, which are common forms of statistical nonnormal distributions, can potentially bias the acceptance pay factor calculations. To examine this potential pay bias, simulations were performed to investigate the magnitude and the direction (overestimation or underestimation) of pay factor calculations. The study revealed that for both one-sided and two-sided specification limits, bias in pay factors not only did vary in magnitude but also reversed in direction over various ranges of PWL. These analyses showed that for a one-sided upper specification limit, on average, a positive skewness and kurtosis can underestimate the pay factor of an acceptable quality level population by 0.90%, and overestimates a rejectable quality level population by 3.8%. This leads to falsely penalizing acceptable products and rewarding bad products. The same was true for two-sided limits, which again varied based upon the percent of defective materials at the tails of the distribution. This is a very important issue because these biases in pay factors can easily upset the relative profit margins of the contractor. Furthermore, this may not be easily detectable without a detailed and sophisticated analysis as outlined in this paper. For multiple quality characteristics based pay factors, analyses showed that the combined magnitude of these biases was not linearly cumulative. Findings of the study indicate that bias in pay was higher for lots with fewer sublots and higher skewness and kurtosis.

This paper focuses on the subject of concurrent delay from a general contractor (GC)-subcontractor perspective. When there is a concurrent delay by multiple subcontractors, or between the GC and other subcontractor(s), there has not been a uniform approach as to how the liquidated damages are apportioned. Previous research seems to ignore this issue. This paper first reviews some relevant court cases. Using a warehouse project as a case study, it then examines different practices that the GC could take in apportioning damages of concurrent delays to both himself/herself as well as to the responsible subcontractors. Results are very inconsistent between and within the apportionment practices. This supports an alternative hypothesis that apportionment is an important issue. Practitioners should specify which apportionment practice will be used and under what circumstances it will be applied in their subcontracts. Researchers may develop a more consistent and reliable approach for this type of apportionment.

A risk/reward model is described as that which aligns project participants’ behaviors toward the achievement of a project’s performance objectives through the use of incentives. A risk/reward model typically includes the following mechanisms: risk/reward shared percentages among nonowner participants, project cost risk/reward, noncost risk/reward, risk cap, and achievability of performance targets. This paper examines the influence of a risk/reward model on the behavior of project participants. Twenty-nine industry practitioners from eight civil infrastructure project alliances were interviewed. The interviews revealed that individual features of a risk/reward model identified had merits, but the achievability of performance targets model appeared to be the most appropriate for promoting positive behaviors within the project team. Additionally, it was found that all incentive aspects of the model examined led to positive and constructive behaviors occurring due to their perceived fairness and equity of payment structure. Participants indicated that having a commercial interest in an alliance’s performance outcomes ensured collaboration and engagement throughout the project’s life cycle. It is concluded that risk/reward sharing is pivotal to obtaining a successful project outcome for the procurement of civil engineering infrastructure projects when using an alliance.

Resource leveling problem is an attractive field of research in project management. Traditionally, a basic assumption of this problem is that network activities could not be split. However, in real-world projects, some activities can be interrupted and resumed in different time intervals but activity splitting involves some cost. The main contribution of this paper lies in developing a practical algorithm for resource leveling in large-scale projects. A novel hybrid genetic algorithm is proposed to tackle multiple resource-leveling problems allowing activity splitting. The proposed genetic algorithm is equipped with a novel local search heuristic and a repair mechanism. To evaluate the performance of the algorithm, we have generated and solved a new set of network instances containing up to 5,000 activities with multiple resources. For small instances, we have extended and solved an existing mixed integer programming model to provide a basis for comparison. Computational results demonstrate that, for large networks, the proposed algorithm improves the leveling criterion at least by 76% over the early schedule solutions. A case study on a tunnel construction project has also been examined.

Schedule delays and cost overruns in large-scale construction projects are caused by a variety of reasons including unrealistic expectations at the planning stage. This paper examines, through computer simulation, the phenomenon of optimism bias regarding organizational dynamics as a potential cause for unrealistic expectations on schedules and budgets. A theoretical framework is introduced to examine how optimism bias regarding organizational dynamics can affect the performance of construction processes. A variety of “what-if” scenarios is tested, and based on our results, we claim that managers who maintain an unbiased attitude during project planning tend to outperform those having either an optimistic or a conservative approach. Therefore, we argue that developing an explicit method for analyzing and taking into account organizational dynamics would be a stepping stone toward adding more realism to construction planning and control practice.

Timely acquisition of construction resource information is an essential task for construction engineers and managers. Due to the harsh and dynamic construction environment, it is not easy to acquire construction information in real time. This paper presents a radio frequency identification (RFID) and ZigBee (IEEE 802.15.4)-based system to manage materials on a busy construction site where a data communications system is not in place. RFID tags are attached to and used to identify various kinds of construction materials, and the ZigBee communication technology is used to wirelessly transfer this information. To confirm the viability of our system, the RFID and ZigBee technologies were assessed using an indoor experiment. Following this, a field experiment was then conducted. On a building construction site, a range of construction materials was identified using RFID tags and this information was transferred to an end user with the help of ZigBee multihop networking. The results of the field experiment showed an acceptable reading range and rate for the proposed system. Therefore, the integrated system with RFID and ZigBee modules demonstrated great potential for improving the existing management processes for construction resources on large and complex construction sites.