Research On Application Of Great Vertical Capacity Rubber Bearing In Isolation Reinforcement Of Continuous Girder Bridges

The 2008 Wenchuan Earthquake caused major human casualties and economic losses in China.Affected by this rare 8.0-magnitude earthquake,the Ministry of Transport quickly issued the “Detailed Rules for the Seismic Design of Highway Bridges” and revised and supplemented the original specifications.Especially in the overall seismic fortification ideas and seismic design methods have great improvements.However,according to the requirement of this specification,most of the existing highway bridges in our country have the problem of insufficient earthquake resistance in different degrees,and there is a huge potential safety hazard.Therefore,necessary seismic reinforcement should be applied to existing bridges that do not meet the requirements of seismic performance.In this paper,based on the energy-dissipation and vibration-isolation capability of Great Vertical Capacity Rubber Bearing(GRB),the application effects of existing continuous beam bridges in seismic isolation and reinforcement are analyzed,and the feasibility of their application in practical engineering is explored.In this paper,firstly,vertical compression and horizontal shear tests are carried out on GRB to study their vertical compression performance and horizontal shear performance;and the influence of bearing dependency on the shear performance of bearings is further studied,such as compressive stress.,shear strain,loading frequency,and repeated loading times.Then,using a four-span continuous beam bridge as the engineering background,a three-dimensional dynamic analysis model of the bridge was established using Midas civil finite element analysis software.(1)Analysis of eigenvalues,comparing the bridge's periodic frequency and modal response under the earthquake-resistant system and the seismic isolation system after the replacement of the bearings.(2)Dynamic time history analysis,comparing the internal force response and displacement response of the critical section of the bridge under both systems,and verifying the strength of the section.(3)Dynamic elasto-plastic time history analysis.Verify the rotation ability of the plastic hinge of the pier column under the two bridge systems.The results show that the bridge isolation system after replacing the original basin bearing with GRB can reduce the bending moment and displacement in the section,and make the force of the whole bridge more reasonable;furthermore,the plastic hinge does not exceed the allowable plasticity of the section.Corners to meet regulatory requirements.It shows that the high bearing capacity isolation bearings have significant effects in the isolation and reinforcement of four-span continuous beam bridges.Finally,in order to compare the effectiveness of the isolation and reinforcement of bridges under different pier heights,the original bridge model was used as a benchmark to increase the pier height by 5m and 10 m.After analyzing the time-course calculation results,it was found that GRB were used in the bridges with low piers.Its isolation and reinforcement effects is better.