VERIFICATION OF THE METHOD FOR IMPROVING ACCURACY OF SIMPLIFIED SEISMIC RESPONSE ANALYSIS OF STEEL RIGID FRAME VIADUCTS

This study is aimed at verifying the usefulness of the estimation method which is able to permit several plastic hinges' occurring to the steel rigid frame viaduct which is higher statically indeterminate. For this purpose, the analytical model, named “whole system model”, which applies shell elements to the place where plastic hinges may form, when the structures are subjected to severe earthquakes, was constructed. Next, Pushover analysis using the whole system model was carried out for evaluating seismic performance of this structure, and simplified seismic response analysis using an equivalent single-degree-of-freedom system model and skeleton curve which resembles a bilinear model based on a result of the Pushover analysis was performed. And then, the results of simplified earthquake response analysis was compared with the result of dynamic analysis using whole system model. Finally, it was contrived to apply a trilinear model to skeleton curve on restoring force horizontal displacement relationship as a way to improve the predictability of the response displacement of this structure. This paper also examines how the accuracy of seismic response analysis using the equivalent single-degree-offreedom system model could be improved