Seismic Response Analysis of Yokohama-Bay Bridge Considering Pounding between Wind-Tongue and Wind-Shoe and Safety Evaluation during the 2011 Great East Japan Earthquake

摘要

During 2011 Great East Japan earthquake, the pounding between the wind-tongue and wind-shoe was observed on the Yokohama-Bay Bridge. If the wind-tongue is damaged by pounding, other members may be damaged serially. However, this pounding phenomena was not considered during design time; safety evaluation of the wind-tongue considering pounding is required. In this study, three-dimensional frame model is constructed. The model is validated by comparing the measurement data with analysis result. Three-dimensional dynamic analysis is then conducted to reproduce the dynamic response considering pounding. Furthermore, nonlinear dynamic analysis using level 2 earthquake ground motions is conducted to clarify the pounding force and to evaluate the safety of wind-tongue. As a result of the dynamic analysis, the seismic response during the Great East Japan earthquake has a good agreement with the observed response by considering the pounding and applying the damping based on the measurement result. In addition, pounding force is shown to exceed the capacity of the wind-tongue during level 2 earthquakes, resulting in shear damage at the wind-tongue base.