Wind and Structures

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Recent Brazilian research on thunderstorm winds and their effects on structural design

  • Riera, Jorge D. (PPGEC, EE, Universidade Federal do Rio Grande do Sul) ;
  • Ponte, Jacinto Jr. (UNISINOS, Universidade do Vale do Rio dos Sinos)
  • Received : 2011.01.28
  • Accepted : 2011.05.31
  • Published : 2012.03.25
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Abstract

Codes for structural design usually assume that the incident mean wind velocity is parallel to the ground, which constitutes a valid simplification for frequent winds caused by sypnoptic events. Wind effects due to other phenomena, such as thunderstorm downbursts, are simply neglected. In this paper, results of recent and ongoing research on this topic in Brazil are presented. The model of the three-dimensional wind velocity field originated from a downburst in a thunderstorm (TS), proposed by Ponte and Riera for engineering applications, is first described. This model allows the generation of a spatially and temporally variable velocity field, which also includes a fluctuating component of the velocity. All parameters are related to meteorological variables, which are susceptible of statistical assessment. An application of the model in the simulation of the wind climate in a region sujected to both EPS and TS winds is discussed next. It is shown that, once the relevant meteorological variables are known, the simulation of the wind excitation for purposes of design of transmission lines, long-span crossings and similar structures is feasible. Complementing the theoretical studies, wind velocity records during a recent TS event in southern Brazil are presented and preliminary conclusions on the validity of the proposed models discussed.

Keywords

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