A holistic seismic performance evaluation of irregular curved bridges with precast segmental piers considering SSI and depth-varying spatial motion inputs

The precast segmental pier (PSP) is recognized as a promising technique for accelerated bridge construction due to its advantages of faster construction speeds and lower environmental consequences. Moreover, irregular curved bridges are commonly adopted in bridge design because of their adaptability to complex terrains. However, limited understanding of the seismic behavior of irregular curved bridges with PSPs (ICBs-PSPs) has impeded the broader application of the precast pier construction approach. This paper proposes a probabilistic method for numerically assessing the seismic performance of ICBs-PSPs subjected to depth-varying spatial seismic motions (DSSMs). The influences of soil-structure interaction (SSI), seismic motion input types, horizontal curvature, and pier column types on its seismic behavior are also systematically investigated. For this purpose, the FE model of a representative ICB-PSPs considering SSI effect is firstly developed in OpenSees. The DSSMs at heterogeneous sites applied to the ICB-PSPs are stochastically synthesized and utilized as inputs to calculate the structural seismic response. Finally, probabilistic seismic demand models based on artificial neural network are employed to compute the seismic fragility of the exemplar bridge. The numerical results underscore the importance of considering SSI and using reasonable DSSMs as input when assessing the seismic behavior of ICBs-PSPs. Moreover, the effect of horizontal curvature on their seismic behavior should be fully taken into account. Compared to the bridge with cast-in-place monolithic piers (MPs), the ICB-PSPs excels in reducing residual displacement after seismic events. The proposed approach can provide a comprehensive understanding of the seismic behavior of ICBs-PSPs constructed on heterogeneous sites, thereby offering vital references for further expanding the application of PSPs in bridge design and construction.