Changing Wind Speed Scenarios and Consequences to Structural Design
Danilo Lima Matias1; Sarah da Silva Andrade1; Débora Maia Silva1; Thiago Dias dos Santos1; Luiz Carlos Marcos Vieira Junior1; André Teófilo Beck2
1 University of Campinas (UNICAMP); 2 University of São Paulo (USP)
doi:10.20906/CPS/CILAMCE2017-0382
Resumo
ABNT NBR 6123:1988 standard provides guidelines to determine wind loading on structures for design purposes. This standard is based on wind speed data documented between 1950 and 1974; hence, it has been outdated for more than 40 years. Moreover, there is ample evidence that climate, and wind regimes in particular, have changed in recent years (Intergovernmental Panel on Climate Change, IPCC and Brazilian Panel on Climate Change, PBMC). This paper aims to present: (i) an updated design chart for basic wind speeds in Brazil, (ii) a simplified maximum annual wind speeds trend analysis for short (5 years), intermediate (20 years), and long term (100 years), and, finally, (iii) a probabilistic study on the effects of the recent changes in the wind speed scenario through a geometrically and materially nonlinear analysis with imperfections (GMNIA) of typical steel moment resisting frames. The updated design chart for basic wind speeds proposed herein is the result of a large data compilation, which comprises early records presented by Padaratz (1977) and data from multiple airport stations in Brazil and neighbor countries available through the Wolfram Research Database (2017). The probabilistic model used to construct the design wind speeds chart was previously proposed in Beck and Corrêa (2012). The simplified maximum annual wind speeds trend analysis was carried out through a linear regression analysis of the historical wind speeds records available. The structural reliability analysis is performed using MASTAN2, McGuire et al. (2000), and Monte-Carlo method. Results show that use of an outdated design chart for basic wind speeds can lead to economic losses due to structural collapse, especially at center-west and northeast regions, where the probabilities of recorded speeds to exceed those given in the standard are up to 14%. The trend analysis indicates that greater attention shall be given to the consequences of a fast changing wind speed scenario and more research shall be carried out on this topic.
Palavras-chave: Wind Speed Chart; Trend Analysis; GMNIA; Data Analysis; Reliability Analysis; Monte Carlo Simulation