Estimates of Peak Roof Displacement Using "Equivalent" Single Degree of Freedom Systems

The accuracy of a new pushover analysis procedure for estimating the peak roof displacement of multistory buildings subjected to earthquake ground shaking is assessed in a pilot study. The energy-based pushover uses a displacement derived from the work done in the nonlinear static (pushover) analysis to establish the capacity curve, in contrast to the use of the roof displacement in conventional pushover analysis procedures. Roof displacement estimates obtained with the energy-based and conventional procedures are compared, relative to the peak values computed in nonlinear dynamic analyses, for three- and nine-story frames as well as an eight-story reinforced concrete wall building. The energy-based approach was found to provide more accurate estimates of the peak roof displacement (in a mean sense) for 17 of the 20 cases considered.