Framework for calculating seismic fragility function of urban road networks: A case study on Tangshan City, China.

The aim of this work is to present a method for calculating seismic fragility function of urban road network. In this paper, urban road system is simplified to a planar network. The spatial correlation of seismic ground motions is considered. The damage probability of network edge is determined by the fragility function of single road section. By repeating simulation, a large number of samples of post-earthquake road network are obtained. Their damage states are classified as minor, moderate, extensive and complete by piece number and diameter of the maximal piece. The seismic fragility function of road network is assumed in the form of lognormal cumulative distribution function and its parameters are identified by fitting the fragility function to the exceeding probability of the damage states. To demonstrate the practicality of the proposed method, an application to the urban road network of Tangshan City is performed. The case study indicates that the rare earthquake may cause the disconnection and fragmentation of the road network with high probability. The proposed framework is a valuable contribution to the seismic performance evaluation of urban road system and provides engineers and practitioners with a tool to design road network in high seismic hazard zone. [ABSTRACT FROM AUTHOR]