A influência do fck no pré-dimensionamento do sistema de contraventamento dos edifícios: uma metodologia para escolha

Abstract

The population increase and the limited physical space in urban centers have caused current buildings to be designed to be increasingly taller and, consequently, slender. Thus, buildings and their structures have become more sensitive to second order effects, which, if not properly considered in structural analysis, can lead to building instability. To verify the need or not to take such effects into account, the parameters of global instability of buildings arose, among which the two recommended by ABNT NBR 6118:2014 are: Alpha Parameter and the Gamma-Z Coefficient. In addition to the concern with the stability of structures, the calculating engineer should always seek the most efficient and, as far as possible, the most economical solution. In view of this, the braced frame structure adopted and the value of the characteristic compressive strength of concrete (fck) recommended are essential to achieve this goal. However, there are situations in which the engineer is forced to work with a specific structural system. Thus, it is the value of fck to be adopted that will ensure the best choice for this situation. In this context, this paper seeks to describe the methodology for defining the most convenient value of fck, for the structural party considered, from the value of Alpha