Influence of Directionality on the Seismic Response of Typical RC Buildings

Abstract

Current seismic analysis contemplates the simultaneous use of the orthogonal components of an earthquake in order to determine the structural stresses closer to reality. This has led to these components being combined considering a fraction of them, as applying them completely would lead to excessively conservative results. However, their application is carried out considering that the direction of the components coincides with the orientation of the orthogonal axes that define the resistant structure. The assumption takes on special importance when it comes to establishing performance demands on a structure based on nonlinear time-history analysis. To establish the proportional relationship between the seismic components, the angle of incidence is used, which is one of the imponderable variables of an earthquake. In this investigation, a group of reinforced concrete structural archetypes with various typologies and regularity in plan is presented, which allow the effect of the angle of incidence in determining the maximum displacement demands to be studied. To study the response, a set of strong earthquakes recorded in Chile is used, obtaining the angle of incidence that produces the maximum displacement demands through interstory drift and roof displacement. A statistical analysis is also carried out in which the influence of the angle of incidence that produces the maximum response is studied.