Response of Building Frames to Earthquake Ground Motions

Abstract

We introduce seismic response analysis for multi degree of freedom building frame systems, particularly for plane frames in this chapter. The equations of motion are first developed for plane frames under external forces and earthquake ground excitation. Static condensation procedure is employed for defining the dynamic degrees of freedom, hence for reducing the total number of degrees of freedom. Then free vibration analysis is conducted leading to natural vibration modes and frequencies. Modal properties are exploited through mode superposition analysis for obtaining dynamic frame response under base excitation. Mode superposition procedure is specialized into the equivalent static response spectrum analysis under modal spectral forces with modal combination rules. Chapter concludes with two special applications, nonlinear static (pushover) analysis and analysis of base isolated buildings.