An Optimization Model for Maximizing the Benefits of Fast-Tracking Construction Projects

Abstract

Fast-track construction projects have become more popular in recent years in response to growing industry demand. By allowing a downstream activity to start with incomplete information from upstream activities, fast-tracking allows for shortening the project duration at the expense of an increased likelihood of rework. This leaves practitioners with the challenge of determining the optimal fast-tracking strategy, which meets project schedule requirements and does not cause excessive amounts of rework. This paper presents an optimization based model that serves as a decision support tool in scheduling fast-track construction projects. The model takes into consideration information exchange between upstream and downstream activities. The objective function of the model is to maximize the net benefits from fast-tracking. Rework time and cost are deduced from the literature on rework in construction projects. The model is illustrated on a small scale case study, which was analyzed under various scenarios. The paper concludes with a discussion of the applicability of the model on complex construction projects.

Modelling the boundaries of project fast-tracking

“…Concerning the monetary aspects, though, there is still uncertainty about how best to model the costs associated with fast-tracking activities [37]. So far, it has only been agreed that the cost of fast-tracking is proportional to the cost of rework, and that the latter is proportional to the overlap.…”

“…In this case, there would be a clear violation (as opposed to a partial override) of the associated precedence relationship. This assumption is also included in most of the recent fast-track models in order to keep the network logic intact [20,26,27,37]. A tighter limit (less overlap) can be introduced, however, if there are other constraints, for example shared resources, space or material handling, between predecessors and their successors [39].…”

“…However, by choosing specific combinations of α and β, homogeneous (for α=1) or heterogeneous (for α≠1) previous models' Poisson information exchange processes can also be incorporated as special cases within the proposed model [26,37,48].…”

“…However, the proportions attributed to overlap and rework, or the probability of rework, are not clear. Some researchers have assumed a linear relationship between cost and overlap [20,27,37], and some exponential [26] or polynomial [39], but these choices have normally been based on subjective assumptions.…”

“…In 2012 and 2013, Khoueiry et al [26,37] developed another optimisation model for fast-tracking construction activities by calculating the probability of rework and its impact.…”