Study On Seismic Performance Of New Lead-filled Steel Tube Damper

Energy dissipation technology has been widely applied and developed in engineering aseismic field.In this paper,the mechanical properties and applications of a new lead filled steel tube damper(LFSTD)are studied by finite element analysis and theoretical deduction.The construction parameters,mechanical properties,design methods and engineering applications of the LFSTD are mainly studied.The main contents and conclusions are as follows:1)39 sets of finite element models for LFSTD with different design parameters are established.The energy dissipation mechanism of LFSTD and the influence of different design parameters,height to diameter ratio,inner diameter of steel pipe,reduction ratio,height of transition section,height of connection section and depth of end plate on the performance of LFSTD are studied,the influence of different structural parameters on the energy dissipation position of the LFSTD is revealed,and the reasonable ratio range of different parameters to the design parameters is obtained,which provides reference for the application of the LFSTD.2)In consideration of the other external effects of the LFSTD in practical engineering,the numerical simulation analysis of the LFSTD under 24 groups of different stress states is carried out to study the influence law of the mechanical properties of the LFSTD in different stress states.The results show that the LFSTD are subjected to axial compression,axial tension,in-plane bending,out of plane bending,torsion and their combination,and the performance of the hysteresis curve is within 5%~10% and shows stable working performance.3)The calculation method of the mechanical parameters of the LFSTD is studied.The calculation formulas of the initial stiffness,initial yield force,strengthening stability yield,yield displacement,ultimate bearing capacity and ultimate displacement of the LFSTD are given.LFSTD with different design parameters have three kinds of energy dissipation: shear type,bending shear type and bending type.With the initial yield theory of a LFSTD combined with the finite element analysis,the initial yield position of the LFSTD with 184 different design parameters is studied,in order to ensure the shear type or bending shear type energy dissipation of the LFSTD,the limit values of the diameter of the steel pipe and the height of the energy dissipation section corresponding to the LFSTD under the different weakening ratio are given.4)The design method of the structure of the LFSTD is studied.The support and pier model of the LFSTD are compared,then the calculation method of the structure demand stiffness and yield force of the additional LFSTD is given.Under the action of the earthquake,the performance objectives of the structure are different,can obtain structural design and fortification of LFSTD under frequent earthquakes and the checking method for LFSTD structure under rare earthquakes.Finally,the design process of the structure of the LFSTD was formed,and a practical engineering project was used as a case to show the whole process of the structure design of the LFSTD.