Direct Inelastic Earthquake Design Using Secant Stiffness

A new earthquake design method performing iterative calculations for secant stiffness was developed. Since basically the proposed design method uses linear analysis, it is convenient and stable in numerical analysis. Moreover, the proposed design method can accurately estimate the inelastic strength and ductility demands of structural members through iterative calculations. In the present study, the procedure of the proposed design method was established, and a computer program incorporating the proposed design procedure was developed. Design examples were presented to verify the advantages of the proposed method. The proposed method, an integrated analysis and design method, can address the earthquake design strategy intended by the engineer, such as limited ductility of the member and the concept of strong column-weak beam. The strength and ductility demands satisfying the given design strategy can be directly determined for all the members. As a result, structural safety and economical design can be achieved.