Research on Very Large Tonnage Bearings and Seismic Mitigation Design for Extradosed Bridge in High Seismicity Areas
The seismic protection performance of the very large tonnage seismic mitigation bearings for extradosed bridges in the high seismicity areas is studied.The Jintan Huanghe River Bridge in Jingyuan County,to which the 20 000 t-grade seismic mitigation bearings are employed,is used as a case.The seismic mitigation system of the full bridge is analyzed.The bearings are designed to have self-lubricating capacity,which is favorable to the precise control of the friction coefficient of the friction pairs,as a result,the bearings can effectively serve the bridge under normal loading conditions(when the friction coefficient is equal to or less than 0.03 and seismic conditions(when the friction coefficient is greater than 0.05).To ensure the wearing-resistant performance of the friction pairs of the bearings,the conventional displacement and rotation friction pairs and seismic mitigation friction pairs are fitted with the wearing plate of modified ultra-high molecular weight polyethylene and the wearing plate of modified polytetrafluoroethylene,respectively.The restrainers are installed on the sides of the bearings for easy replacement in the future.The performance indicators of the bearings,including the strengths of various components,shear resistance of the shear pins and mechanical property,were verified via numerical simulation,shear test of the shear pins,and scaled-down model test of the bearings.The seismic mitigation system of the full bridge was numerically simulated.The response spectrum method and time history analysis method were utilized to analyze the strengths of the piers and pile foundation,shear displacement of the bearings,and movements of expansion joints.The results demonstrate that the cross-sectional flexural capacity of the transition piers and pile foundation,shear displacement of the bearings at main piers as well as the widths of the expansion joints at the transition piers meet the requirements.
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万方数据
维普
