EUROCODE 8-Part 2, Bridges: time history presentation of seismic action for base isolated bridges

摘要

The purpose of the investigations presented herein has been to show a developed and verified method for presentation of seismic action by a time history. These investigations are related to Eurocode 8, Part 2, Bridges, and have involved the use of recorded accelerogrammes obtained from occurred earthquakes. Themethod introduces optimization bywhich, for a period equal to the natural period of vibration of a structure, the ratio between the square root of the sum of squares of the spectra computed from both horizontal components of a single record-SRSS and the code spectrum is computed. While performing this task, pairs of horizontal components for which this ratio is equal or greater than 1.0 (up to a tolerance value) are selected for nonlinear dynamic analysis, provided that the scaling factor is limited. Verification of the method is given for a base isolated bridge on E-75 motorway, with a natural period of 1.4 s. Also, some important recommendations and discussions related to the presentation of the code spectrum by a time history are given.