IMPACTS OF DIFFERENT OBJECTIVE FUNCTIONS ON RESOURCE LEVELING IN CONSTRUCTION PROJECTS: A CASE STUDY

Atilla Damci,Gul Polat

doi:10.3846/13923730.2013.801909

Atilla Damci, Gul Polat

Open Access

https://doi.org/10.3846/13923730.2013.801909

Copy DOI

Abstract

A review of the recent literature on the models that focus on resource leveling in Critical Path Method networks shows that different objective functions have been used to optimize resource utilization. The main objective of this study is to investigate the impacts of using different objective functions on resource utilization histograms in Critical Path Method networks. For this purpose, nine different resource leveling objective functions were optimized via a genetic algorithm-based model. The model was developed using actual data obtained from a steel framed industrial building construction project. It was found that each of these objective functions generates different resource utilization histograms. In order to determine the improvement levels achieved by resource leveling using nine different objective functions, the improvement percentage in each parameter and the average improvement percentage for each objective function were calculated. Even though the objective function that involves the minimization of the sum of the square of the deviations in daily resource usage provided the best average improvement percentage in the studied case, another objective function(s) may provide better average improvement percentage in different projects. The contractor should consider all objective functions for resource leveling and select the one(s) that provides the best average improvement percentage.

Highlights

There are several scheduling techniques, such as Gantt charts, Critical Path Method (CPM), and Program Evaluation and Review Technique (Pert) used in construction projects
The main objective of this study is to investigate the impacts of using different objective functions on resource utilization histograms in CPM networks
In order to determine the improvement levels achieved by resource leveling using nine different objective functions, the improvement percentage in each parameter and the average improvement percentage for each objective function were calculated

Summary

Introduction

There are several scheduling techniques, such as Gantt charts, Critical Path Method (CPM), and Program Evaluation and Review Technique (Pert) used in construction projects. The main objective of this study is to investigate the impacts of using different objective functions in leveling resources in CPM networks For this purpose, a genetic algorithm-based model was developed and tested using actual data obtained from a steel-framed industrial building project. Reviewing the literature on resource leveling in CPM networks in order to determine the objective functions that are used in optimizing resource utilization; 2. Senouci and Eldin (2004) presented a genetic algorithmbased model that performs resource leveling and resource constrained scheduling simultaneously with an objective function that attempts to minimize absolute deviations between daily resource usage. Doulabi et al (2011) developed a genetic algorithm-based model that allows activity splitting, using an objective function that minimizes the sum of the absolute deviations of the daily resource usage from the average daily resource usage. Start time ≤ Start time of the activity ≤ Early start time +Free float (2)

Minimization of the sum of the square of daily resource usage

Findings

Conclusion