Abstract

Realizing safety improvements in construction site layout planning (CSLP) is vitally important to construction project safety management. Unlike previous studies in which the safety objective is built without detailed risk factors analysis, this study transforms CSLP into a multi-objective optimization (MOO) problem with designing two safety objective functions due to facility safety relationships (potential risks arising from interaction flows) and geographic safety relationship (potential risks arising from hazardous sources) from the holistic interpretation of interaction relationship connecting temporary facilities. Besides, a supplementary cost reduction objective function was also derived as cost is a critical barrier against safety improvement. Subsequently, a triobjective ant colony optimization based model was developed to solve MOO problem. Finally, a case study is used to verify the proposed model. The study enriches safety implications by considering onsite safety issues from interaction relationship and enhances site safety of CSLP in the pre-construction stage.

Introduction

Construction site layout planning (CSLP) is a critical activity that should, ideally, be given full consideration to early in the pre-construction stage of construction projects. Various researchers have discussed the significance of “design for safety” and argued that most accidents or serious risks can be avoided by incorporating more safety considerations into planning schemes [1–۴]. It is significantly beneficial and vital to improve construction site safety through better site layout in safety planning, and thus the considerable attention paid to safety planning in the pre-construction stage is critical to improving project safety performance efficiently [5].

CSLP is commonly treated as an optimization problem, and site safety can be realized by designing different objective functions based on safety requirements or considerations (hereafter called “safety objective function”), such as minimizing accidents by optimizing safe locations for tower cranes [6–۸], controlling hazardous materials onsite [9, 10], reducing intersections between heavily traveled routes [11], defining the safety zones in term of necessary regulations [12], and reducing the noise pollution onsite [13, 14]. With a specific safety objective function, the generated site layout plan can only fulfil the partial safety requirement mentioned above. In previous researches, limited attention has been paid to designing safety objective functions with full risk factor evaluation involved in the function design. Developing safe construction site layout plans under the partial safety objective function without adequate and further risk factors analysis will result in layout with more risk tendency. Thus, this study was conducted with the objective of designing safety objective functions with full consideration of onsite safety after holistic risk factors analysis associated with site layout.