f KHOSHNOUDIAN - Department of Civil Engineering, Amirkabir University of Technology, Tehran, Iran
a HEMMATI - Ms.c in Civil Engineering, Amirkabir University of Technology, Tehran, Iran,

Double concave friction pendulum (DCFP) system is the new developed kind of friction pendulum systems that consists of two sliding surfaces. In the current paper, the seismic response of three dimensional base-isolated structures using DCFP systems considering trilinear and bi-linear behaviors have investigated. After deriving the coupled differential equation of motion, a computer program has been developed in order to obtain the time history response of base-isolated structures under earthquake excitations. Advantages and disadvantages of trilinear behavior over bi-linear one are scrutinized by studying the effect of main parameters such as isolation period, amplitude of the ground motion, and friction coefficient of the surfaces on the peak responses under seven earthquakes. It is demonstrated that tri-linear DCFP bearings, in comparison with bi-linear bearings, can decrease the base shear up to about 48 percent. However, tri-linear DCFP bearings cause bigger displacements of sliding surfaces than bi-linear ones that reach to 57%.

Double concave friction pendulum (DCFP), tri-linear, bi-linear, isolation period, radius of curvature, friction coefficient