| Wind load is one of the most important load of the building structure. It is very important to resist wind load for building structures. High-rise buildings have lower frequencies, which are closed to the predominant frequency of wind load. The structures of glass curtain wall have light weight. So some times wind loads have become control load for these two kinds of structures. It is necessary to do deep studies of wind engineering.In the early 1960s, the work of Davenport had made great progress of wind engineering. The wind load is evaluated as mean and fluctuating components. The fluctuating wind can be saw as a stationary gauss random process and its power spectral density was developed. The"gust response factor"method, introduced by Davenport as a classics method for computing the wind-induced dynamic response in along-wind, has been developed and applied in almost all the current standards of the major countries. The gust response factor is defined as the ratio between the peak fluctuating displacement response and the mean displacement response.The point-supported glass curtain wall has been widely used all over the world for its good architectural effect and rational mechanical properties. The characteristics of point-supported glass curtain wall are greatly different from the traditional structures, that induced the lag of theories. For example, the Technical code for glass curtain wall engineering(JGJ102—2003) did not use the gust response factor, but the gust wind factor. As large-span and high curtain walls have been widely used, which induced greater dynamic response, the use of gust wind factor will bring on unfavorable result. The gust response factor developed in the load code for the design of building structures(GB 50009-2001) was based on the model of cantilever beam, which is different from the supporting structure of point-supporting glass curtain wall. So this paper developed a method for the calculation of the gust response factor for the point-supported glass curtain wall. Based on random vibration theory, the response of the structure under random wind load and the formula of wind vibration factor was developed. The veracity of this formula was proved by the results of numerical simulation. Then, this paper studied the supporting structures which are fixed-supported and which are not on the ground. Based on the result of former studies, differently-supported revise and over-ground-base revise are developed for wider application. This formula can be conveniently applied in engineering practice for its comparability with the formula in the load code and it also can be regarded as a reference for code revision. It is greatly convenient to use the equivalent wind load for structure design. But the wind load is an random process and the wind-induced response is also a random process, so the equivalent wind load is probabilistic. So the reliability analysis of equivalent wind loads is developed in this paper. Based on the peak amplitude distributing of stationary gauss stochastic process, this paper developed a formula for calculating the dynamic reliability. Different from the Gauss distributing method, Rayleigh distributing method and Poisson process method, this method considered the influence of the spectral bandwidth parameter, so it had better precision and applicability.Based on the formula of the dynamic reliability analysis, the reliability of the equivalent wind load was calculated. For the feasibility of this work, the randomicities of the partial factors, the body coefficient and the exposure factor are been ignored. Finally a numerical example demonstrating the rules is given. |
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