Professor T.T.Soong is one of the early pioneers in fi eld of earthquake response control of structures.A new type of smart damper,which is based on an Energy Dissipating Restraint(EDR),is presented in this paper.The EDR by Nims and Kelly,which has a triangle hysteretic loop,behaves like an active variable stiffness system(AVS) and possesses the basic characteristics of a linear viscous damper but has diffi culty in capturing the output and large stroke simultaneously needed for practical applicataions in engineering structures.In order to overcome this limitation,the friction surface in the original Sumitomo EDR is divided into two parts with low and high friction coeffi cients in this paper.The results of f inite element analysis studies show that the new type of smart friction damper enables large friction force in proportion to relative displacement between two ends of the damper and has a large allowable displacement to fi t the demands of engineering applications.However,unlike the EDR by Nims and Kelly,this type of friction variable damper cannot self re-center.However,the lateral stiffness can be used to restore the structure.The nonlinear time history analysis of earthquake response for a structure equipped with the proposed friction variable dampers was carried out using the IDARC computer program.The results indicate that the proposed damper can successfully reduce the earthquake response of a structure.
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