Aseismic Reliability Analysis Of Bridge Structures Based On Probabilistic Pushover Method

Bridge plays an important role in Lifeline System engineering. During an earthquake event, it is critical keeping running of the road transport network for avoiding secondary disaster and resuming production as soon as possible. So correct seismic analysis and seismic design are very important in bridge structure design. Since many uncertain factors exist and the action of earthquake are random, the design method of reliability based on the probability and statistics is the scientific measure which ensures the bridge's safety under the earthquake and security estimate for the seismic design of the bridge.In this paper, based on the Pushover method, statistical strength reduction coefficient model is applied, based on probability pushover method, apply random earthquake model to consider the randomicity of the earthquake. Seismic reliability of the deterministic intensity and in reference period for 50 years were evaluated. The below works were completed in this paper:1,First of all, the development process of the bridge aseismic design methods was systemmatically reviewed. The state-of-the-art of Pushover method, strength reduction coefficient and aseismic reliability were introduced.2,The basic principle and the implementation steps of the pushover method were introduced. The common distribution patterns of the lateral load were adduced, for instance, uniform distribution, inverted triangle distribution, parabolic distribution, the first mode distribution, mode combination distribution and adaptive localization, etc. The solution method of target displacement was summarized, mainly including displacement coefficient method, capacity spetral method and elastic-plastic response spectrum, and so on.3,The strength reduction coefficient models were systemmatically reviewed. By utilizing the 1064 strong ground motion records obtained from the destructive event in the history, which were classified according to the site classification and characteristic period group specified by the design code of China, the inelastic response of SDOF systems with variant periods and ductility coefficients were analyzed by BISPEC program. Then, based on the strength reduction factor model proposed by Nassar & Krawinkler, the calculation results were analyzed with statistical regression method. Thereby the strength reduction factor model that was compatible with the seismic design code of China is obtained.4,The calculation method of the aseismic reliability for the structural engineering was researched, including the calculation of seismic reliability of balanced failure and randon balanced failure mode, and numerical simulation method for seismic reliability.5,Seismic reliability of the Ma Zhangba bridge was analyzed by probabilistic Pushover method which combining deterministic Pushover method with probabilistic response spectrum and considering the randomness of target spectrum with randon earthquake model.