Seismic Fragility Study Of Bridge Based On Historical Damage Data

Bridges are the key nodes in road-net. Bridges under strong ground motion arerelatively more likely to be damaged than other components of highway system. A largenumber of bridges in our country are located in the seismic region. Earthquakes cancause major damage to the bridges, which can interrupt the traffic. American andJapanese did more research in bridge seismic vulnerability analysis. The study on bridgeseismic vulnerability analysis in our country is not completed yet. It is an urgent need toimprove study of bridge seismic vulnerability since it is useful for traffic systemreliability analysis and bridge damage assessment. Based on the history seismic damagedata of bridges, the analysis of typical seismic damage of bridges is presented, statisticalanalysis was carried out in various ways, the bridge seismic vulnerability curves arepresented and their rationality are verified, different vulnerability curves are comparedand what causes the results are analyzed.The main content of the paper is as follows:1. The main research methods of bridge seismic vulnerability analysis are presentedcomprehensively, the principle vulnerability analysis methods in this paper areintroduced in detail. The existing damage classification methods are introduced.2. Domestic bridge seismic damage data is collected. The typical bridgesearthquake examples are analyzed, and the bridge seismic damage data are sorted inseveral groups to obtain statistical results, such as damage matrix.3. The bridge seismic damage statistical data are sorted by the bridge types and theregion. Two-parameters lognormal distribution function is used to represent thevulnerability curves, these two-parameters are estimated by the maximum likelihoodmethod or least square method estimate. Vulnerability curves Obtained are comparedwith statistical results to verify the rationality.4. Vulnerability curves obtained in this paper are compared with each other andwith those obtained in other countries, and what causes the results are analyzed.Through comparison of vulnerability curves, in which situation vulnerability curve canbe applied is pointed out.