摘要：As an important part of lifeline project, bridge structure has obvious impact on the smooth progress of earthquake relief work due to its post-earthquake integrity and timely reparability. The seismic fragility of an engineering structure refers to the possibility of different degrees of damage of the stmeture under the action of earthquakes with different strengths, or the probability of the structure to reach or exceed a certain limit state. Ttic cxtra-long-span bridge is very different in structure performance from the conventional span bridge especially under the action of earthquake, and it is impossible to make accurate judgments on the structural performance and damage of the extra-long-bridgc with prc\aous analysis methods and experience. Therefore, it is very important for the extra-large-span bridge to analyze the seismic behavior of the stnicturc. especially the sequence of earthquake damage and the probability of damage under earthquake action. On the basis of summarizing and analyzing previous research works, this paper takes a lung-span steel truss arch bridge as an example, establishes a full-bridge finite element model, and analyzes its seismic fragility under random earthquake situation in terms of the damage form, damage indicators and risk assessment with the numerical simulation method. The study results show that the probability of bridge seismic damage increases with the increase of service life, and the bridge is more prone to damage along with its longitudinal bridge, showing cctlain ductility during the damage process and small probability of complete damage. The results of this paper will provide a reference for further study on the risk assessment of seismic fragility of bridge structures under random earthquake.
