Influence of the geometric nonlinearity and the aerodynamic damping on the dynamic response of tall buildings

Resumo

In recent decades, the increasing of slenderness in buildings structural design has been relevant leading to the reduction of the natural frequencies values and the damping levels, resulting in excessive vibrations and human discomfort, in some situations. Having in mind the current day-to-day project practice aiming to determine the dynamic structural response of tall buildings, two aspects are generally disregarded, associated to the effect of the geometric nonlinearity and the aerodynamic damping. Therefore, this research work aims to assess the dynamic structural behaviour of a steel-concrete composite building with 48 floors and 172.8 m height, when subjected to wind nondeterministic actions, including in the dynamic analysis the effects of the geometric nonlinearity and the aerodynamic damping. The building numerical model was developed to obtain a realistic representation of the analysed structural system, based on the Finite Element Method (FEM), through the use of the ANSYS software. The conclusions of this study, obtained based on the displacements and accelerations values, pointed out to the fact that the effect of the geometric nonlinearity led to relevant differences on the dynamic structural response of the investigated building. On the other hand, the contribution of the aerodynamic damping was not significant.