Chapter 1 - Overview of Seismic Critical Excitation Method

Abstract

This chapter presents a detailed overview of seismic critical excitation method. It begins by defining the critical excitation. It is natural to imagine that a ground motion input resonant to the natural frequency of the structure is a critical excitation. The method of critical excitation was proposed by Drenick for linear elastic, viscously damped SDOF systems in order to take into account inherent uncertainties in ground motions. This method is aimed at finding the excitation producing the maximum response from a class of allowable inputs. It was suggested that the critical excitation introduced by Drenick is conservative compared to the recorded ground motions. To resolve this problem, the concept of “subcritical excitation” was introduced. The concept of critical excitation may enable structural designers to make ordinary buildings more seismic resistant. However, critical excitation problems for fully non-stationary excitations and critical excitation problems for elasto-plastic responses under those excitations are challenging problems.