Journal of Construction Engineering, Management & Innovation
There has been considerable literature written on the benefits of design-build (DB) project delivery method. Numerous research on this topic compared design-bid-build (DBB) to design-build based on cost and time, but little has been written to evaluate both delivery methods based on scope definition and differing site conditions. This research sought to investigate scope definition change orders and differing site condition change orders on Washington State Department of Transportation (WSDOT) design-bid-build and design-build projects. This research quantitatively analyzed if significant differences exist and if such differences are statistically significant enough to be attributed to the project delivery methods used. The research used available data from WSDOT on projects completed from 2002 to 2016. There were 1813 new design-bid-build projects and only 28 new design-build projects completed within this period with the first design-build project awarded in 2002 for the Sr 16, New Tacoma Narrows Bridge awarded for $615M. This paper presents a snapshot of the state of design-bid-build and design-build delivery methods at WSDOT from 2002 to 2016. Based on the data analyzed for this research, there were no significant differences in the two project delivery methods considering contract changes related to scope definition and differing site conditions.
Building and infrastructure objects are no longer exclusively realized by processing materials at construction sites, but increasingly through on-site assembly of elements produced off-site. When designing an object whose realization is based on construction parts that are produced off-site, it is important to also consider the assembly of the components at the building location. Unfortunately, insufficient attention has been paid so far to interaction between the systems that are created through the realization of assembly processes. This inhibits achieving the full potential of using assembly processes. It manifests itself through issues such as dimensional deviations between the original design and the assembled system and also disappointing aesthetic results. These considerations have led to the general conclusion that the design and realization phases of construction processes are insufficiently aligned and that more attention should be given in the design phase to the on-site assembly of the various construction parts. This article describes the development of a design-for-assembly methodology for construction and infrastructure projects. An initial version of this design-for-assembly method was applied in five construction projects and in one infrastructure project. Based on the results of the case studies conducted, further improvements were implemented leading to a final version of the design-for-assembly method. In addition, three validation workshops were organized involving thirty experts from the field of construction and infrastructure site management. A large majority of the experts concluded that the developed design-for-assembly method was a valuable addition to the design and realization process for building and infrastructure objects. Once these steps have been described, this article ends with a discussion on the scientific contributions made, the managerial implications, and offers directions for future research.
Noor Hussein Farooq Albayati
In construction project management the critical path method (CPM) is the most commonly used technique for project scheduling. Although this technique provides many advantages for project managers, it cannot efficiently deal with the allocation of the resources. Therefore, alternative techniques have been introduced to address resource allocation requirements of the projects. Of these techniques, Resource Leveling (RLP) aims to minimize the fluctuation in resource usage histograms while maintaining the duration obtained by CPM. Resource Constrained Project Scheduling Problem (RCPSP), on the other hand, aims to secure the shortest CPM duration without violating the resource constraints. RLP and RCPSP are vital for effective utilization of project resources (e.g., manpower, machinery, and equipment) as they help precluding intermittent usage or over-allocation of the resources. Keeping the resource usage at a relatively constant level through RLP would result in a decrease in the overall project cost as the additional costs required to demobilize and remobilize the resources will be minimized. Shortening the makespan while meeting the resource constraints through RCPSP would lead to improved resource utilization and cost savings as well. The main objective of this study is, therefore, to analyze effectiveness and efficiency of the most widely used commercial project management software packages in solving resource allocation problems. To this end, the most recent versions – as per the date of this study – of three software packages, namely, Microsoft Project Professional 2019, Primavera P6 Professional 2019, and Asta Powerproject version 15.0.01.489 are examined. The performance of the practiced software are evaluated based on thirteen different priority rules over a set of problem instances available in the literature. The practiced problems include 640 instances providing a diverse combination of network complexity, activity number, and resource type number. Results obtained by the software for RCPSP are also compared with the solutions provided by the Serial Scheduling Scheme – a heuristic method. The findings of this study reveal that whilst all the three software packages manage to provide comparable results, Asta PowerProject transpire to be the all-round best performing method while Primavera sports the fastest leveling module. This study also sheds light on the challenges and practical hurdles to utilization of the aforementioned software for resource allocation purposes.
The majority of international trade in goods is carried by maritime transport with higher volume for developing countries. Therefore, considering the enormous contribution of marine construction projects to economic growth, they have become one of the most crucial construction types in many countries. For this reason, the completion of these projects on time has critical importance on the local economy. However, marine construction poses serious risks compared to other construction works, resulting in possible delays since they have significant differences in design and construction. As a result, delay factors identified for different construction projects cannot be transferred directly to marine projects. This study identifies significant delay factors encountered specific to marine construction projects, a crucial gap in the literature. Subsequently, their relationships are examined and approved by experts. We also proposed a Bayesian Belief Network predictive model for estimating schedule delays in the marine project, carried out by a case study. The results show that the delay duration can be predicted using the proposed model before the marine project starts. Also, the identification of dependencies between the delay factors has practical advantages. Practitioners could define the cause-effect relations and prevent delays by focusing on the origins of the delay factors unique to developing countries.