Análise do coeficiente de pressão interna de uma edificação em função da direção do vento e das áreas de abertura

Abstract

One of the challenges found in structural engineering when designing a project is to obtain the value called internal pressure coefficient of the structure to the posterior calculus of mechanical stresses. It is important to accurately obtain the value of this coefficient, since it directly influences the mechanical stresses suffered by the structure's frames, and consequently in the choice of the most appropriate metal and steel for its construction. Besides, the ABNT NBR 6123/1988 standard suggests constant values throughout the entire structure in specific situations and often these predicted specifications do not fully cover the situations found in the practical design. Considering the limited scope specified by the standardization and the knowledge of the fact that the values of the internal pressure coefficient are subject to changes due to the opening areas of the structure, geometry and the angle of incidence of the wind, this research has as main theoretical purpose to analyze the magnitude of the variation of the internal pressure coefficient as a function of the geometric factors of the structure (opening areas) with different wind incidence angles, as well as measuring the accuracy of the use of numeric simulations tools to obtain the intern pressure coefficient through a direct comparation with the values suggested by the standard. To complement the research, a case study was selected, in which a structure of simple geometry, predicted by the standard, was placed to fluid dynamics simulations in the ANSYS software. In each of the simulations the structure has been exposed to different opening areas, as well as different wind incidence angles. The values of the intern pressure coefficient were obtained in the simulations and in the ABNT NBR 6123/1988 standard and directly compared. As a result, it was possible to verify how these values vary depending on the increase or decrease of the structure opening areas, besides compare the fluid dynamics simulations results with the standards results in similar situations.