Alongwind static equivalent wind loads and responses of tall buildings. Part I: Unfavorable distributions of static equivalent wind loads

Although on the same theoretical basis, the current standards of major coun tries have set out two evidently different distributions of alongwind stati c equivalent wind loads, one being the same as the mean wind force and the other the same as the first mode shape on tall buildings. In this paper, th e fluctuating static equivalent wind load is evaluated as mean, background and resonant components, and the unfavorable distribution of each component is separately addressed. Meanwhile. the wind loads by the above two code m ethods are derived. The effects of the wind loads by the two code methods o n tall buildings are then examined to identify whether or not they are equi valent with regard to the actual wind induced responses. The results show t hat the wind loads by the two code methods can only ensure an equivalent fi rst mode displacement response, and they may lead to some considerably unfa vorable load effects, for example, the base shear force estimation. Finally a numerical example demonstrating the main results is given. (C) 1999 Else vier Science Ltd. All rights reserved.