Performance-based Seismic Design For RC Bridges

Bridges hold the key positions in the communication and transportation system. Once they are destroyed in earthquakes, there will be great difficulties for the emergency managements and bridges restoration. Performance-based seismic design is a revolution of the seismic design concept and is the development trend of project in the 21st century. Static elastic-plastic pushover analysis with the virtue of being practical attracts more and more attention, and is incorporated into Code for seismic design of buildings(GB50011—2001).The basic theories,steps of analysis and the recent achievements about pushover analytical method are discussed and the method is applied to evaluate seismic resistance capacity of bridges structure in this paper. The inelastic response demand spectrum of four site condition is gotten by employed Vidic's strength reduction factors method based on response spectrum of Code for seismic design of buildings(GB50011—2001). it has the advantage of that structural periods represented by radial lines intersecting demand spectra with different ductility factors are all the same. The multiple performance objectives are usually expressed as that designed structures can resist against minor earthquake without any damage, resist against moderate earthquake with repairable structural damage and resist against strong earthquake without collapse.Seismic damage models are studied from both material lever, member level and system level. The relationship is recommended between the damage index and the seismic damage grades of the structure for bridges.A method of Didplacement-based seicmic design and evaluation of seismic capacity is developed for bridge piers. The basic principle of this method and the selection of the seismic performance parameter and the seismic damage model are researched, and the procedure for applying this method is provided.