Study On Performance Of New Lead Core Damper For Continuous Beam Bridge

With the development of railway bridge construction in China,the application of seismic isolation technology is more and more widely,and the lead damper technology has a good development prospect.At present,there are few researches on the composite damper composed of lead core and high performance materials.Based on the mechanical characteristics of continuous beam bridge,a new type of lead core damper is proposed by combining lead core with polyurethane,which is a high performance material.The seismic isolation performance,design method and effect of lead core damper are systematically studied by using numerical analysis method.1.The seismic isolation design requirements of railway continuous beam are analyzed,and the basic conditions of seismic isolation device suitable for railway continuous beam are determined;The structure,working principle and characteristics of the new lead core damper are introduced;The constitutive model of lead core material is determined,and the damping force model of the new lead core damper is analyzed theoretically.2.The hysteresis performance of the new type lead core damper is studied by numerical simulation.The accuracy of the simulation method is verified by comparing with the experimental results;Several common models of restoring force are analyzed and the new type of restoring force model of lead core damper is determined;The influence of the lead core size on the damper parameters is studied;The size of the new type lead core damper for continuous beam bridge is determined,and its hysteretic and mechanical properties are analyzed.3.Several common seismic design methods are analyzed,and the seismic design method adopted in this paper is determined;The theory of equivalent linearization method and common calculation methods are analyzed,and the equivalent linearization method of each part of continuous beam bridge with new lead core damper is determined,and the simplified mechanical model of continuous beam bridge system is established;The calculation method of seismic reduction and isolation design of continuous girder bridge with new lead core damper is formed,and the calculation steps and flow chart are given.4.According to the new layout of lead core damper,the longitudinal time history analysis of continuous girder bridge under three working conditions is carried out.The comparison shows that the corresponding layout of working condition 2 has better damping effect,the new lead core damper can play a strong energy dissipation capacity,reduce the seismic response of fixed pier of continuous girder bridge,and make full use of the residual strength of movable pier.The seismic capacity of the whole continuous beam bridge is improved.The simplified calculation of seismic reduction and isolation design of continuous girder bridge under condition 2 is carried out,which is in good agreement with the time history analysis results and verifies the accuracy of each other;In this paper,viscous dampers are used to reduce and isolate the continuous beam bridge.The damping effects of the new lead core damper and viscous damper are compared,and their respective characteristics are analyzed.