Drift Capacity at Axial Failure of RC Structural Walls and Wall Piers

Abstract

A large number of reinforced concrete (RC) buildings constructed prior to the mid-1970s in earthquake-prone regions rely on lightly reinforced or perforated perimeter structural walls to resist earthquake-induced lateral loads. These walls are susceptible to damage when subjected to moderate-to-strong shaking; a number of such cases were observed in past earthquakes. Despite these observations, there are limited studies reported in the literature that investigate the loss of axial (gravity) load-carrying capacity of damaged walls and wall piers, primarily due to limited experimental data. This study utilized a comprehensive database that includes detailed information on more than 1,100 RC wall tests. To study wall axial failure, the database was filtered to identify and analyze data sets of tests on shear- and flexure-controlled walls. The findings indicated that axial failure occurs in flexure-controlled walls with special and ordinary detailing, and that axial failure mechanisms include complex phenomena influenced by various parameters. For diagonal shear-controlled walls, axial failure results from sliding along a critical crack plane extending diagonally over the height of the wall when the shear friction demand exceeds the shear friction capacity. Based on the results, expressions were developed to predict lateral drift capacity at axial failure of RC walls and piers.