NUMERICAL TECHNIQUE FOR DYNAMIC ANALYSIS OF STRUCTURES WITH FRICTION DEVICES

In recent years a number of studies on employing friction elements for the seismic protection of buildings has demonstrated conclusively tha t such devices can markedly reduce earthquake-induced vibrations. Any numerical estimate of the effectiveness of such isolation systems impl ies a correct solution of the pertinent nonlinear equations of motion. In direct integration algorithms, the phase transitions between adher ence and sliding, or the sliding phase may be accompanied by marked hi gh-frequency oscillation of the relative velocity difference. The pape r presents a numerical technique for overcoming these problems, thus l eading to increased accuracy of the solutions of equations of motions with Coulomb damping, Since only the damping matrix and the loading ve ctor are involved, the procedure is also computationally efficient. In order to validate the proposed numerical technique, an experimental s tudy of a friction system has been carried out. The dynamic response o f a four-storey braced frame with friction devices is presented as an example for the practical application of the proposed numerical techni que.