Direct search approach to optimum spiral column design

Abstract

An optimum design algorithm for spiral columns is formulated based on the structural behaviour of spiral columns. A brief review of the reinforced concrete (RC) structural optimization and the spiral column behaviour is presented. The sections of spiral columns which satisfy code requirements are stored in the database and are manipulated by one major variable, i.e. the section identification number (N) which is linked with all other design variables, such as overall section dimensions, steel ratios, positions of reinforcement and resistant capacities, cost per unit length, etc. In design procedures, a continuous or preliminary solution is obtained first, based on regression curve equations, and then an effective direct search for the discrete optimum section is carried out. The convergence and reliability of the proposed algorithm are demonstrated through numerical examples.