Reproduction of Cable-Stayed Bridge Seismic Responses Involving Tower-Girder Pounding and Damage Process Estimation for Large Earthquakes

Tower-girder transverse pounding was observed on the Yokohama Bay Bridge wind tongue during the 2011 Great East Japan Earthquake. Damage to the wind tongue due to pounding can potentially lead to damage of other members. However, pounding was not taken into consideration in the design, and the process of how the damage occurs after the wind tongue damage has not been clarified. Therefore, a way to model the damage process involving tower-girder transverse pounding is needed. In this study, a frame model of the Yokohama Bay Bridge was constructed to reproduce the observed damage that occurred as a result of the pounding. A multiscale model was then constructed by combining the global frame model with a local finite-element model consisting of a shell and solid elements. The model was validated through comparison with actual measurements. Dynamic analysis of the multiscale model clarified the deformation of the wind tongue during large earthquakes and the resulting damage to the bridge. The model demonstrated that ductile damage can occur at the base of the wind tongue during a Level 2 earthquake and that the tower link can then drop off due to its large displacement after the wind tongue damage.