Optimization of material hoisting operations and storage locations in multi-storey building construction by mixed-integer programming

Material storage locations incurring minimum transportation costs in construction are a common construction management problem. Storage locations influence the delivery path and overall project efficiency. Lower floors of buildings after completion and developing sufficient structural strength will be utilized as storages and layout plans should be designed to achieve maximum construction efficiency in terms of total transportation and distribution costs. A mixed-integer programming is formulated to optimize the vertical hoisting and storage layout solvable by a branch-and-bound technique. Total transportation cost is derived as an objective for optimization. Material storage locations are defined as binary variables. Linear constraints are developed to satisfy design requirements. A numerical example storing 10 material types and delivering materials in a 30-storey building is given for illustration. Numerical results optimized by the MIP approach will be compared with those optimized by the genetic algorithms. The MIP solution shows better solution quality taking less computing time.