Optimized multi-tower crane layout planning: determine height, location and type to improve operational safety

Purpose In high-rise construction projects, the use of multiple tower cranes to transport materials has become common; however, optimizing their layout still poses a challenging problem. Key objectives such as minimizing costs related to crane operation (such as rental, installation, dismantling and operator wages) while reducing workdays, mitigating interruptions caused by crane overlapping and improving safety (such as preventing crane collisions and path blockages). Design/methodology/approach A mixed-integer linear programming (MILP) model is proposed to optimize the number, type and location of tower cranes as well as the location and number of supply points. The MILP incorporates crane height optimization and penalties for loading, crossing and unloading within overlapping areas to tackle interference issues. Additionally, a delay penalty is introduced into the objective function to minimize workdays and material delivery delays. Findings The proposed method was validated with a real-world case study. Results show that the introduced model can manage crane overlaps optimally by assigning tasks and ranking crane heights. Unlike similar works, the proposed method is able to find a path over other cranes by determining an optimum height. Applying the proposed method in the case study resulted in a cost reduction of up to 49%. Originality/value This study extends the previous approaches by addressing critical yet underexplored factors such as the number and capacity of supply points as well as considering safety issues like avoidance of path obstructions and crane collision(s) in the mathematical model.