DYNAMIC COMPARATIVE ANALYSIS OF THE RESPONSE OF A BUILDING SUBJECTED TO WIND ACTION IN THE FREQUENCY DOMAIN FOR FUTURE PROPOSAL TO THE NP-196

Resumo

The accelerated growth of urban centers and the exponential development of real estate
industry have led to an increase of the construction of tall buildings. In addition, thanks to
technological advances, new construction methodologies have emerged that make structures slenderer.
In this sense, wind action is of fundamental importance in the structures design, especially on a
national level, due to the high wind speeds perceived in recent years and that have cause structural
collapses.
The national wind code NP-196 does not consider the dynamic action of high winds in slender
structures. Some international wind codes consider such action through an amplification factor (gust
response factor). Others, such as NBR-6123, present a simplified methodology of a probabilistic
analysis. Both methodologies arise from the spectral density response of a typical building by applying
a theoretical spectrum of wind gusts. In this context, the present work aims to analyze such
methodologies through the application of the mentioned theoretical spectrum on a building, in order to
suggest pertinent recommendations for a future proposal of the dynamic action of wind in structures.
For this purpose, a dynamic comparative analysis is made of the structure response through vibration
theory in the frequency domain. The spectrum of the fluctuating component of the wind force and
response spectra were obtained for different theoretical power spectral density of wind velocity,
suggested by several authors. The gust response factor for each case analyzed is then obtained as well
as the static equivalent fluctuating force, both of which are related to wind codes. Finally, a
comparative analysis is presented in which the variation of the wind force over the structure remains
under 10%, between different velocity spectrums.