Effects of Loading Conditions and Hoop Details on Residual Axial Load Capacity of R/C Columns Failing in Shear

Abstract

In order to avoid pancake-type collapse of existing old R/C buildings during severe earthquakes, it is necessary to evaluate the residual axial load capacities of the existing R/C columns. These "residual axial load capacity" is defined as the axial load carrying capacity of a column after the column suffers serious damage; it corresponds to the safety limit. The standard popularly used in Japan for the evaluation of seismic performances of existing R/C buildings includes evaluation methods for residual axial load capacities, which have dramatic effects on seismic performance indexes. The objectives of this study are to examine the residual axial load carrying capacities of R/C columns after shear failure. We have focused on the loading methods and the confining effects of hoop reinforcement depending on the reinforcing details of the columns.