Analysis of seismic mitigation and isolation measures for long-unit PC continuous girder bridge in high-intensity area
In order to clarify the seismic mitigation and isolation performance of sliding friction pendulum bearings of long continuous prestressed concrete(PC)girder bridges in high seismic intensity areas,a nonlinear analysis model of space beam element of a long-unit PC continuous girder bridge with seismic fortification intensity of 9 degrees was established using CSiBridge software.Based on the seismic response of ordinary spherical steel bearing,the seismic isolation performance of lead rubber bearing and sliding friction pendulum bearing was compared and analyzed,and the friction coefficient and bearing curvature of sliding friction pendulum bearing were analyzed.The results show that,compared with the lead rubber bearing,the sliding friction pendulum bearing has better seis-mic isolation effect,less internal force and deformation of the fixed pier,and more uniform and reasonable force for the long-unit con-tinuous girder bridge.For sliding friction pendulum bearings,the greater the friction coefficient,the greater the bending moment at the bottom of the fixed pier and the displacement at the top of the pier of the long continuous beam.The amplitudes of variation for friction coefficient,maximum bending moment at the bottom of the fixed pier,and the extreme displacement at the top of the pier were found to be 20%,1.67%,and 1.45%,respectively.The radius of curvature of sliding friction pendulum bearing has little effect on the seismic isolation performance of the long continuous beam.The radius of curvature increases by 1.5 m,the maximum bending moment at the bottom of the fixed pier increases by 0.97%,and the displacement at the top of the fixed pier increases by 0.37%-1.39%.
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