Response of Sliding Rigid Structure to Base Excitation

Abstract

The rectilinear motion and the conditions of reattachment and separation of a rigid body, in friction contact with another body are considered. A graphical representation of the motion is indicated, and analytical expressions for the velocities and displacements are derived. The existence of limiting values of velocity and displacement is shown for a special class of periodic ground motions which include harmonic motions. Also, the equations of motion and the conditions of reattachment and separation of a two degrees of freedom model of a sliding structure and foundation are derived. The numerical integration of the response of this system is carried out, as well as a parametric study showing the effect of different values of the mass ratio, coefficient of friction and amplitude of the ground acceleration. Use of results of the parametric study, concerning amount of slippage, resonance frequency ratios, minimum allowable frequency for sticked mode, etc. in the design for structural base isolation is indicated.