Fragility-based seismic performance assessment of modular underground arch bridges

Seismic performance assessment of modular underground arch bridges (MUABs) can help mitigate structural damage to MUABs during earthquakes. This study proposed an efficient procedure to evaluate the seismic performance of a three-hinge MUAB by using fragility-based analysis. Firstly, a novel proposal for damage states was presented using the relationship between the crack depth and thickness of the arch component. The relationship between ground motion intensity and structural failure probability was then described using stratum uncertainty characteristics. The multiple stripe analysis approach with the maximum likelihood function was introduced to detail the uncertainty characteristics of strata by allowing various ground motions at distinct seismic intensity levels. Finally, the collapse probability considering stratum-uncertainty characteristics was specified for seismic intensity and probability levels. The results revealed that the proposed procedure to randomly select ground motions from the strong-motion database of the Pacific Earthquake Engineering Research Center is feasible for evaluating the seismic vulnerability of MUABs. Therefore, the seismic performance of MUABs can be reasonably predicted under earthquakes.