This report summarizes the results of a research conducted at the University of Colorado, Boulder, aimed at developing a PC-based software tool for performing nonlinear pushover analysis of reinforced concrete buildings. The program links two libraries to an existing finite element program, FEAP, developed at the University of California, Berkeley. The two
libraries are a) a frame element library (which includes beam, beam-column and shear wall elements); and b) a library of uniaxial material laws. The project first modified the existing program to perform nonlinear pushover analyses on a routine basis. Current seismic code suggested procedures for nonlinear pushover analyses were then reviewed. The applicability of nonlinear pushover analyses to the seismic design of reinforced concrete frames was evaluated by studying the response of frames of different heights. The responses of static and dynamic nonlinear analyses on the same buildings were compared. A new shear element was then introduced and a typical shear wall of a utility core was analyzed with a push-over analysis. Details on the features added to program FEAP and on the new commands are documented in the appendices.