Abstract
A method to evaluate the performance of new and existing structures subjected to earthquakes is proposed. This method, derived from the Capacity Spectrum Method, can be used by practicing engineers in the design of new buildings and in the evaluation of existing buildings and retrofit methods. Capacity curves for the overall structure and for each story level are established from an inelastic pushover analysis. The pushover analysis is based on stiffness dependent story shear demands. Seismic story demand points for a given earthquake are determined for initial elastic response and for various levels of structural ductility using response spectrum analysis and modal superposition. The increase in total equivalent viscous damping during the shaking due to the development of hysteretic damping is reflected in the demand points. These points are then joined to form individual demand curves for each story and for the overall structural response. The demand curves are then superimposed onto the capacity curves. The proposed procedure is applied to a one-third scale, three story reinforced concrete frame model building which was subjected to successive shaking table excitations and to the same building after retrofit subjected to the same shaking table excitations. The predicted response found using this method are compared to experimental measurements obtained in the shaking table tests and to the results from nonlinear dynamic analyses. Various additional earthquakes are then used to excite the buildings in order to demonstrate the predictive use of this method. The predicted analytical response from these additional excitations are compared with results obtained from nonlinear dynamic analyses. This study shows that the proposed method can be used to predict the response of a structure to a given earthquake with reliable results.
O'Boyle, Margaret (1996). Evaluation methodology for structures subjected to seismic loading. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1996 -THESIS -O26.