Mechanical Analysis Of Laminated Rubber Bearings Considering The Eccentric Vertical Pressure,Torsional Moment

The laminated rubber bearings are assumed to be under axial vertical load during the analysis procedure of its mechanical performance.However,in some engineering projects,the bearings are subjected to eccentric vertical load in some situations,e.g.,when the bearings are used to support side columns or the shear walls around an elevator hoist-way,meanwhile,the laminated rubber bearings may experience a torsional moment due to asymmetry of the superstructures in the case of horizontal one-way earthquakes.Existing models for predicting the behavior of the laminated rubber bearings can not be used for eccentric vertical pressure and torsional moment conditions.Thus,in this paper,an analytical model considering the eccentric vertical pressure,torsional moment of laminated rubber bearings will be proposed.Revealing the influence of the eccentricity and torsion angle on the mechanical properties of the laminated rubber bearings.Firstly,this paper introduces vertical eccentricity into the framework of Koh-Kelly model and Iizuka model meanwhile establishing an analytical model considering the eccentric vertical pressure.The variation of mechanical properties of laminated rubber bearings under vertical axial pressure and vertical eccentric pressure is analyzed.Then,establishing an analytical model considering torsional moment of laminated rubber bearings.The variation of mechanical properties of the laminated rubber bearings within torsion is investigated.And verify the effective of the theoretical model by comparing with experimental data.Through the analytical model,main findings can be summarized as follows:(1)The vertical buckling load and critical horizontal displacement of the bearing underthe vertical eccentric pressure decreases with the increase of the eccentricity on theeccentric side.(2)Under the vertical eccentric pressure,the mechanical properties of the vertical displacement and rotation angle of the laminated rubber bearings decrease with the increase of the eccentricity on the eccentric side.(3)The critical bearing capacity of the seismic isolation bearing will decrease as the torsional loading increases.