Benefits of Using Nonlinear Analysis on Seismic Retrofit from Structural Engineering Standpoint

Nonlinear static procedure (NSP) or pushover analysis is becoming a popular tool for seismic performance evaluation of existing and new structures. It is believed that the pushover analysis will provide adequate information on seismic demands imposed by the design ground motion on the structural system and its components. Nonlinear pushover analysis was recommended by FEMA 356 — Prestandard for Seismic Rehabilitation of Buildings, which currently adopted into a standard called ASCE 41-06 — Seismic Rehabilitation of Existing Buildings, in assessing the seismic performance of buildings for a given earthquake hazard representation. This purpose of the paper is to examine the effectiveness and benefits of nonlinear static procedure for seismic response analysis of reinforced concrete buildings. This study focuses on one of the low-rise hospital buildings located in Orange County, California. This building was constructed in the early 60's with a reinforced concrete shear wall system and it is a non-compliant building per current building code. In order to meet the code requirements, the building was analyzed and retrofitted based on the results from nonlinear pushover analysis. By implementing this advanced analysis approach, structural performance was better understood which led to the more efficiently use of retrofit methods.