ON MODELING ACTIVITY CRASHING AND OVERLAPPING: A FIRST ALGORITHM

Abstract

Accelerating construction projects is a commonly used method for meeting the project deadlines and/or compensating for current delays. There are several approaches to speed-up a project, such as activity crashing and overlapping. Activity crashing means reducing activity durations through adding more resources. Activity overlapping means executing certain activities in parallel when they were supposed to be sequential in the original plan. Construction management literature is mostly focused on studying each acceleration mode separately, while the focal point of this paper is to develop a joint model and a first algorithmic implementation that involves both acceleration methods. Particularly, on reviewing the project management and scheduling literature, a mathematical model combining activity crashing and overlapping is reformulated. Also, a Genetic Algorithm is implemented on a fictitious case study. Preliminary findings of the model and algorithmic implementations identify that activity crashing alone and a mixed approach are preferred when significant compression is required, whereas activity overlapping is recommended for minimizing compression costs when only a small compression is required.