The effects of the wave passage on the response of base-isolated buildings on rigid embedded foundations, 1993

In this report, the response in the frequency domain is studied for a building on rubber bearings subjected to incident plane P- and SV-waves and surface Rayleigh waves. A simple two dimensional soil-structure model is used, in which the building is represented by an equivalent single degree-of-freedom (SDOF) oscillator or a uniform shear beam, on a circular rigid foundation, which is embedded into a homogeneous elastic half-space. The soil-structure interaction is included. For simplicity, all the deformations are assumed to be in linear range. The response of this model is compared with the response of the commonly used fixed-base model.; It is concluded that, as a result of the soil-structure interaction, the relative building response is further reduced, but the overturing moment of the inertia forces of the building about its base is significantly larger, because of the larger rocking amplitudes of the foundation. Also, it is shown that, for incident waves for which the foundation input motion has considerable amount of rocking, relative to the amplitudes of the horizontal motion, the transfer function amplitudes of the relative building response are larger at the frequency of the second mode, than at the first mode. The opposite trend is noticed for isolated buildings on a rigid base.