Wave-passage effects on seismic responses of pile–soil–cable-stayed bridge model under longitudinal non-uniform excitation: shaking table tests and numerical simulations

Abstract

A pile–soil–cable-stayed 1/70-scale bridge model was designed and constructed to represent an extremely long-span cable-stayed bridge with a 1400-m central span. Shaking table tests were conducted to investigate the wave-passage effects on the seismic responses of the pile–soil–cable-stayed bridge model under uniform and non-uniform longitudinal excitations. Additionally, the acceleration frequency spectra and seismic responses of the bridge model were separately evaluated to compare the effects of uniform and non-uniform excitation. Finally, a 3-D finite element model in OpenSees was built for comparison with the test results. The results showed that the longitudinal wave-passage excitations considerably impacted the acceleration frequency spectra in the vertical direction of the girder and the modal participation factor, which resulted in the symmetric vertical bending mode shapes of the girder to increasingly affect the seismic response as the wave-propagation velocity decreased. The longitudinal wave-passage excitations increased the vertical responses at the 1/2-span of the girder, whereas they generally decreased the longitudinal responses of the girder and tower, as compared with uniform excitation. The longitudinal wave-passage excitations had different impacts on the pile–soil interaction effects for the three studied structural systems of the pile–soil–cable-stayed bridge model. Moreover, the dynamic characteristics and seismic responses obtained from the numerical simulations were consistent with the experimental results.