Refined Study On Seismic Pounding Responses Of Simply-supported Skewed Girder Bridges Under Earthquake

The seismic responses of the skewed bridges are different from the nonskewed bridges because of their particular and complex characteristics and the skewed bridges suffered severe seismic damage in the past devastating earthquakes. In order to analyze the influence of the horizontal ground motion direction, the skew angle and the vertical ground motion to simply-supported skewed bridge, a refined 3D point to surface pounding model of simply-supported skewed bridge that can consider the impact of friction was established with OpenSees software. The main contents are as follows:(1)Based on comprehensive reading of related literatures home and abroad, the seismic damage and the issues about seismic pounding of the skewed bridges were reviewed and summed systematically. Details of the deck modeling method in the skewed bridges and the main pounding models were introduced.(2)The reliability of the point to surface pounding model of simply-supported shewed bridge was verified and it was also demonstrated that the model can capture the refined seismic responses. The results show that the position that produce the maximum impact force changes with the change of the skew angle; The friction between deck and abutment weakened the influence of the skewed angle to the largest longitudinal displacement in acute position of deck’s ends; The peak rotation angle of deck may be overestimated without considering the friction effect.(3)The influence of the horizontal ground motion direction to seismic pounding responses of the simply-supported skewed bridge was analyzed. The results indicate that when the skew angle is ?, under considering the longitudinal pounding effect between deck and abutment, the horizontal ground motion direction that the minimum value of the maximum longitudinal displacement and the peak rotation angle appear in is ? ?(90? ??); when considering the effect of longitudinal pounding between deck and abutment and transverse pounding between deck and restrainers, the seismic pounding responses will get more complicated, and the bigger skewness, the higher complexity.(4)The effects of skew angle to simply-supported skewed bridge was investigated under considering the horizontal ground motion direction, it can be find that only considering the longitudinal pounding effect between deck and abutment, the maximum longitudinal displacement in deck’s ends and the peak rotation angle of the deck will increase with the skew angle’s increase; considering the joint pounding effect of longitudinal pounding between deck and abutment and transverse pounding between deck and restrainers, the maximum longitudinal displacement of deck’s ends will increase with the skew angle’s increase and the peak rotation angle presents the changing law of increasing first and decreasing then with the increase of the skew degree.(5)The action of the vertical ground motion to the seismic responses of the simply-supported skewed bridge was analyzed and discussed. It can be found that the vertical ground motion has certain influence to the uplift force of bearings and seismic pounding responses that consider the sliding of bearings.