Studies On Shock Absorption Of Lead-Rubber Bearings On Bridges

Earthquake damage to railways and highway bridges is very serious,The bridge of advanced seismic design theory and effective shock absorption technology is more important.Lead-rubber bearings,combining with characters of shock isolation and damping,and advantages of low cost,easy manufacturing,material availability,and stable mechanical properties,Lead rubber bearing has been widely studied and applied in the field of engineering.This paper focuses on the following aspects in investigating shock isolation properties of lead-rubber bearings:The energy dissipation principle of lead-rubber bearings is introduced and dynamic properties of beam structures are analyzed.Starting from the dynamic equilibrium equation,and incorporating with small deformation theory,plane cross-section assumption,and displacement and boundary conditions,the author obtains the mass,element stiffness,and element damping matrixes.The general Finite Element Analysis(FEA)software-ANSYS-is used to construct the finite element model of lead-rubber bearings utilized in actual bridge engineering,and to study and verify the bi-linear regression model.Modal analyses are respectively performed on whole bridge structures with only laminated rubber bearings,or lead-rubber bearings.Results show natural frequencies for bridge structures with lead-rubber bearings decrease.The seismic time history of the two models was analyzed by using Tianjin earthquake wave.Respectively,the corresponding displacement time history curve,stress time curve and basic reaction time curve.The shock analysis was obtained by contrast analysis.The results show that the impact resistance of the lead rubber bearing is better than that of the plate rubber bearing.The influence of the height of the bridge pier on the shock absorption effect is studied.The results show that the damping effect of lead rubber bearing is reduced with the increase of pier height.