Calculated accelerograms for the direct dynamic method of determining seismic loads

Abstract

Summary To calculate the seismic stability of objects by the direct dynamic method of seismic loads, computed accelerograms are required. The article shows that the use of accelerograms, which do not take into account the soils amplification properties of the particular study site, can lead to incorrect engineering calculations of the seismic resistance of buildings. The article considers the question of how different the maximum acceleration at the same input motion (in the form of an accelerogram) at different sites located close to each other. The results of modeling the amplification of one and the same input motion by the soil strata of two different sites are presented. The sites have a similar geological structure. The bedrock is at the same depth. Geographically, the sites are located at a distance of 10 km from each other in Kiev on the right bank of the Dnieper. Under such conditions, when designing seismic resistant objects, design engineers for emergency load combination calculations usually use the same set of design accelerograms. The modelling results presented in this article showed that the soil amplifications of the same input motion, even on closely spaced and, at first glance, sites with similar geological structure, may differ significantly.