Design of friction damped structures using lateral force procedure

A trilinear model is used to simulate the seismic resisting mechanism of a single-degree-of-freedom friction-damped system to reflect the situation in which both dampers and frame members lose their elastic resistance. The se ismic response of the friction-damped system is normalized with respect to the response of its corresponding linear system by an approach that incorpo rates a credible equivalent linearization method, a damping reduction rule and the algebraic specification of the design spectrum. The resulting close d-form solutions obtained for the normalized response are then used to defi ne a force modification factor for friction-damped systems. This force modi fication factor, together with the condensation procedure for multi-degree- of-freedom structures, enables the establishment of a quasi-static design p rocedure for friction-damped structures, which is intended for the benefit and use of structural practitioners. A curve-fitting technique is employed to develop an explicit expression for the force modification factor used wi th the proposed design procedure; it is shown that this simplification resu lts in satisfactory accuracy. Finally, a design example is given to illustr ate the validation of the proposed design procedure. Copyright (C) 2000 Joh n Wiley & Sons, Ltd.