Abstract
In the earthquake resistant design concept, frame structures are usually designed with a column over design factor (COF) to ensure the preferable failure mode during earthquakes. Initially, in the present study, the failure modes of multistory ductile frame structures are investigated probabilistically by applying the first order reliability method (FORM). The base shear distribution of the International Building Code (IBC-2006), which adopted the seismic design provisions of ASCE 7-05, and the Ai distribution of the Building Standard Law of Japan are taken into account in this study. Based on the investigations, the target values of the COF that probabilistically ensure the preferable entire beam hinging failure mode prior to story collapse are evaluated and compared. The study has been conducted for different reliability levels and the corresponding COF values are presented in this paper.
