Shake-Table Test for a Typical Curved Bridge: Wave Passage and Local Site Effects

Abstract

To study the effects of ground motion spatial variations on curved bridges, this paper presents a shake-table test for a 1/10-scale typical curved bridge under spatial ground motions, including wave passage effect, local site effect, and ground motion multidimensionality. The experimental results show that both wave passage and local site effects have significant influence on seismic responses of curved bridges. Wave passage effect on curved bridges is attributed primarily to the higher asymmetric modes and pseudostatic displacements induced by asynchronous excitations, whereas local site effect is more obvious for structures with fundamental frequencies close to the predominant frequencies of the sites. Compared with straight bridges, the curvature radius causes curved bridges to be more sensitive to ground motion spatial variations, especially the local site effect. Therefore, curved bridges may be damaged more seriously than straight bridges during the same earthquake. Furthermore, seismic responses of irregular curved bridges are more sensitive to ground motion multidimensionality than are those of straight bridges. In this experiment, the effects of bridge abutments and nonuniform sites along the bridge were not considered.