An Analytical Approach for Design of a Structure Equipped with Friction Dampers

Abstract

This study proposed simply design procedure of a single degree of freedom (SDOF) structure equipped with friction dampers. General method is suggested in order to reduce the structural seismic response by using friction dampers. The analysis model was transformed into an equivalent mass-spring-dashpot system by approximating nonlinear friction damping force with equivalent viscous damping force. A closed form solution for dynamic amplification factor (DAF) for steady-state response was derived by the energy balance equation. The equivalent damping ratio was defined by using DAF at natural frequency. The transfer function between input harmonic excitation and output structural response was obtained from the DAF, and the response reduction factor of the root mean square (RMS) for displacements without and with friction dampers was analytically determined. Using the proposed procedure the friction force required for satisfying given target response reduction factor was obtained. Mean response reduction factors matched well with the target values based on the dynamic analysis results. It is concluded that the proposed method is quite simple for the design of friction dampers to reduce seismic response of the structure.