Torsion-based layout optimization of shear walls using multi-objective water cycle algorithm

In shear wall-based buildings, locating the shear wall in plan has an important role in the resistance of seismic loading. In this article, the minimum torsion is considered as one of the main goals for optimal layout of shear walls, unlike the common method that accepts a certain torsion limit. The method presented is in accordance with the principles of design codes with emphasis on reaching the least possible torsion effect. By using a multi-objective function, based on the Pareto solutions, the torsion function behaves against the cost of a structure subjected to constraints of flexural strength, shear strength, and drift. This approach has the ability to layout shear walls in irregular plans and those which have high architectural limits. Also, it can fulfill the main goal of a structural engineer in order to satisfy the requirements of an architectural plan and obtain its minimum torsion effect as well. This method has been applied to various types of regular and irregular plans according to the classification of seismic design codes. Results show that besides minimizing the cost, the torsion effect reaches the minimum possible value considered by the seismic design code, as compared with other methods.