Along-wind dynamic analysis of and determining the gust loading factor (GLF) for large single-column billboards

Document Type : Research Article

Author

Department of civil engineering, Islamic Azad University, Khormouj Branch, Khormouj, Iran.

Abstract

The effective role of billboards for advertising has led to the expansion of their use in open spaces and public places. The large panel area and light weight have made billboards sensitive to wind, and many cases of their damage have been reported recently. The design of structures against wind force is generally done with the gust loading factor (GLF) method. However, this method is specific to tall structures in most codes and standards, and there are no relations for billboards. In this research, the along-wind responses and the GLF have been calculated for large single-column billboards using frequency domain analysis of MDOF models using MATLAB software. First, an example of a tall billboard was presented and the responses of the structure and the GLF were determined for it, and the effect of basic wind speed and area roughness on the GLF was investigated. Then, billboards with different geometric specifications were designed and analyzed against wind load. According to the results, aerodynamic damping was one of the important factors limiting vibration, especially in rough areas. The GLF increased with the decrease of structure’s height and increase of ground roughness, in such a way that it reached 4.71 for the urban area and 10 meters high billboard, which indicates the high importance of vibrations of billboard is in this situation. Due to the high dynamic response, the safe and resistant design of these structures requires the accurate determination of the GLF.

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