Design wind loads for local flexible cladding of structures based on wind tunnel tests

Abstract

Damage and ultimate failure of cladding elements may play an important part in the wind-resistant performance of structural system. Particularly for those claddings made from lightweight and flexible materials, they are more sensitive and vulnerable to wind excitation. This study proposes an approach of reducing the design wind loads for the local flexible cladding of structures, where the significant geometric nonlinear effect of the cladding is considered. In the light of stress equivalence principle and finite element analysis, the equivalent design wind load for the local flexible cladding is presented with consideration of reducing extreme wind pressure which is usually used for the design of rigid cladding and resulted from statistical analysis of experimental pressure measurement. In view of characteristics of wind pressure distribution on local flexible cladding units, the reduction coefficient of extreme wind pressure at varying wind directions is also given to build wind load evaluation system for the flexible cladding. The effects of wind pressure gradient and correlation on determining the design wind loads are respectively quantified by fluctuating factor and synchronous factor in order to further explore their action mechanism. Moreover, a case study is performed to examine the effectiveness and reliability of this proposed approach in actual application, where the results of extreme wind pressure, reduction coefficient and relevant influencing parameters are analyzed. It proves that this evaluation system is not limited by the external geometry of structures, and can help to optimize the wind-resistant design of the cladding economically, especially for the local flexible cladding susceptible to variation of fluctuating wind pressures.