Genetic Algorithm for Solving Site Layout Problem with Unequal-Size and Constrained Facilities

摘要

This paper presents an investigation of the applicability of a genetic approach for solving the construction site layout problem.This problem involves coordinating the use of limited site space to accommodate temporary facilities so that transportation cost ofmaterials is minimized. The layout problem considered in this paper is characterized by affinity weights used to model transportation costsbetween facilities and by geometric constraints that limit their relative positions on site. The proposed genetic algorithm generates aninitial population of layouts through a sequence of mutation operations and evolves the layouts of this population through a sequence ofgenetic operations aiming at finding an optimal layout. The paper concludes with examples illustrating the strength and limitations of theproposed algorithm in the cases of ~1! loosely versus tightly constrained layouts with equal levels of interaction between facilities; ~2!loosely versus tightly packed layouts with variable levels of interactions between facilities; and ~3! loosely versus tightly constrainedlayouts. In most problems considered where the total-objects-to-site-area ratio did not exceed 60%, the algorithm returned close to optimalsolutions in a reasonable time.