Response of Pure-Friction Sliding Structures to Three Components of Earthquake Excitation Considering Variations in the Coecient of Friction

In the present study, the in uence of the coecient of friction on the seismic response of sliding base isolated structures is investigated. The building is modeled as a simpli ed single-story structure resting on a group of sliding supports. The frictional forces mobilized at the sliding supports are assumed to have a hysteretic plasticity behavior. Bilateral interaction between the sti ness of the two horizontal orthogonal directions of the isolators has been taken into consideration. The results show that the variations of the coecient of friction in uence the response of a sliding base isolated building. E ects of vertical excitation on the normal and frictional forces are considered too. The in uence of the bi-directional interaction of frictional forces and vertical excitation on the response is investigated by comparing the response of the system to mono-directional (excluding vertical component and no interaction between the two horizontal orthogonal directions), bi-directional (excluding vertical component) and tridirectional earthquake excitations. It is demonstrated that the response of the sliding isolated structures is in uenced signi cantly by the bi-directional interaction of frictional forces and by incorporation of the vertical component. Further, the base shear response may be underestimated if the e ects of the vertical component are neglected and the sliding structures are designed merely on the basis of single-component or two-component excitation.