Avaliação do comportamento estrutural dinâmico não determinístico de edifícios altos considerando-se o efeito da ação transversal do vento e a modelagem da interação solo-estrutura

Abstract

In the last few decades, large Brazilian cities have shown substantial growth in relation to the design and construction of tall and slender buildings. This architectural trend has produced flexible structural systems, with very low natural frequency values; and therefore, more susceptible to excessive vibration problems, coming from the wind dynamic action. According to this context, it is necessary that the buildings structural analysis can be carried out more precisely, considering the wind dynamic actions, in a more realistic way, based on the correct definition of their nondeterministic dynamic properties. This way, it should be noted that in addition to considering the wind longitudinal dynamic actions (along-wind), the dynamic actions acting on the structure in relation to the transverse direction (across-wind), caused by the existence of vortices, also must be taken into account in the analysis. On the other hand, the relevance of considering the soil-structure interaction (modelling of foundations) is highlighted, having in mind the influence of this effect on the structure global stiffness. Therefore, this research work aims the investigation of the nondeterministic dynamic structural behaviour and the human comfort analysis of tall buildings. Thus, in this study three building projects are considered: two reinforced concrete buildings with heights of 90 m and 140 m, respectively, and one building based on a steel-concrete composite structure with a total height of 173 m. The Spectral Representation Method (MRE) was used to characterize the longitudinal wind dynamic actions. The effect of wind dynamic actions associated to the transversal direction (vortex effect) was conceived based on the development of an analysis methodology called the Modified Spectral Representation Method (MRE-M), considering the coefficients obtained through the use of data from experimental tests carried out in a wind tunnel. The results achieved in this study demonstrate the relevance of modelling the soil-structure interaction, which contributes to the decrease in the natural frequencies values; and, consequently, it produces an increase in the buildings longitudinal and transversal accelerations. It is also noteworthy that in most design situations, the transversal accelerations present higher values, thus representing a key factor for the analysis and verification of the tall buildings human comfort.