INFLUENCE OF SEISMIC LOAD SPECTRUM ON THE DYNAMIC RESPONSE OF STRUCTURES

The response of structures such as multistory buildings to seismic excitations is considered. The seismic excitations are represented in the form of nonstationary random processes. The influence of the fundamental characteristics of the seismic spectrum-the dominant frequency and bandwidth-is studied. These characteristics depend on the soil and geological conditions in the site. It is shown that the response of the structure can vary within a wide range for close values of the maximum acceleration and period of the intensive phase of motion in the site. It is established that in the resonance region, a considerable spread occurs both in the maximum displacements and accelerations and in the residual strain and residual load-carrying capacity of the structure. Away from the resonance, the influence of the spectral distribution of the seismic excitation on the response of the structures is relatively small. This fact can be used in calculations in the case of insufficient information about the motion in the site.