Investigation on the seismic performance of single-span RC frame school buildings retrofitted with wing walls under different seismic design intensities

Abstract

School buildings with single-span reinforced concrete (RC) frames had been widely constructed in southern China before 2008 Wenchuan Earthquake. The use of wing walls is a very convenient way to enhance the seismic performance of such buildings. In this study, the applicability of wing walls for seismic retrofit of old existing single-span RC frame school buildings is systematically examined under different seismic design intensities. An improved random pushover analysis method is developed in order to perform seismic vulnerability assessment and reliability analyses. A typical single-span RC frame school building was selected as the prototype structure, which was designed for various seismic design intensity degrees according to the new seismic design code (GB50011-2001) and the old seismic design code (GB50011-2010 (2016 edition)), respectively. Three types of structures, including new code-designed structures, old code-designed structures and old code-designed structures retrofitted with wing walls are investigated with extensive seismic vulnerability assessment and reliability analyses. The analysis results indicate that the seismic performance of old code-designed structures can be improved significantly after being retrofitted with RC wing walls. Under lower seismic design intensities, wing wall-retrofitted structures behaved similarly well with the corresponding new code-designed structures. Under higher seismic design intensities, the seismic performance of wing wall-retrofitted structures were not improved sufficiently to meet the requirement of the new seismic design code.