Single Driven Constraint Optimal Structural Design of Tall Buildings Under Period Constraint

Abstract

Period constraint is important for the design of super tall buildings. Structural design of numerous super tall buildings is governed by period constraint. Reducing period of tall building may cause excessive stiffness requirement and will induce massive waste of structural member material. Proper vibration period is critical index for the optimal structural design of super tall buildings. The authors developed a series of sensitivity based optimal structural design methods for super tall buildings. The design criteria for tall buildings can be treated as constraints in optimal design, which can be divided into three classes: global constraints, assembly constraints and component constraints. If certain constraint has been considered in solving design variables, it will be defined as driven constraint, otherwise the constraint will be defined as validation constraint. Sensitivity analysis is concerned with the relationship between design variables and the structural response. Based on the sensitivity results, an engineer can decide on the direction of design alternation needed to improve the design effectiveness. In this paper, the formulas for the sensitivity coefficient of vibration period to the structural members are derived, based on which single driven constraint optimal method for structural optimization under period constraint is developed. According to the sensitivity coefficients, cost effective structural design can be achieved by reasonably redistributing materials amongst different sets of structural members. A 468-m tall building project is employed to illustrate the applicability and effectiveness of the proposed optimal design method under period constraint.