Characterization of pounding effects in curved girder bridges using multidimensional seismic demand parameters

Curved bridges exhibit pronounced bending–torsion coupling and spatially nonuniform responses under earthquake excitation because of their curved alignment. To characterize these complex response features, this study adopts pounding force, residual deformation, and pier-base energy dissipation as seismic demand parameters from the three dimensions of force, deformation, and energy. Four refined finite element models are developed for a three-unit, ten-span highway curved bridge with four commonly used support systems, while nonlinear behaviors such as pounding are explicitly considered. Incremental dynamic analyses are conducted using near-fault and far-fault ground motions to investigate the mechanisms through which pounding affects structural damage and to evaluate the effects of different influencing factors. The results indicate that the proposed combination of seismic demand parameters can effectively characterize the seismic response of curved bridges and assess seismic damage. While transverse pounding restricts the displacement of the main girder and reduces the residual deformation of the bearings, it alters the force transfer path, leading to increased pier energy dissipation and aggravated damage. Furthermore, according to the parametric analysis results, lead rubber bearings can reduce the probability of pounding by restraining the main girder displacement; however, pounding cannot be completely avoided under near-fault ground motions. Unlike straight bridges, curved girder bridges can still develop significant bidirectional response demands under unidirectional ground-motion excitation, and nominally identical components at different locations can exhibit substantially different responses. For example, Pier 2 exhibits the highest energy dissipation, nearly three times that of Pier 5, which exhibits the lowest. This study establishes a multi-parameter “force–deformation–energy” evaluation framework for curved bridges, verifies its effectiveness and necessity, reveals the influence of different factors on pounding responses, and provides a more comprehensive analytical basis for the seismic performance assessment of curved bridges.