A Seismic Design Procedure for Different Performance Objectives for Post-Tensioned Walls

A method is presented for the design of unbonded post-tensioned concrete walls for seismic loading to satisfy multiple performance objectives. It takes advantage of the fact that the initial stiffness of the wall is nearly independent of the amount of post-tensioning reinforcement, and thus the fundamental period of the building can be considered to be a stable parameter in design of walls of a given cross section, independent of the degree of post-tensioning. The design spectra used to follow the specification provided in Eurocode 8 considering the probability of exceedance of the seismic action. A detailed example is provided.