A Simplified Analysis of Flutter and Buffeting of Cable-supported Bridges

• Main Authors: Yi-Ching Chang, 張怡慶
• Other Authors: Yuh-Yi Lin
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/90474342572046003462

碩士 === 淡江大學 === 土木工程學系碩士班 === 93 === Some simplified formulae for the prediction of flutter critical wind speeds and buffeting responses were examined and compared to the precise theories in this study. Three bridge models, with different bridge decks and spans, were chosen as the examples. For the simplified flutter analysis, three formulae respectively used in the Chinese code, Japanese design manual and Austrian code and one proposed by Selberg were examined. The effects of vertical and torsional frequencies on the flutter critical wind speeds were also studied through a parametric analysis. The results show that all the flutter critical wind speeds calculated from the four simplified formulae are lower than those from flutter theory. Among them, the formula used in the Japanese manual is the most conservative and the Selberg formula is the closest to flutter theory. Since the buffeting calculation is more complex and tedious than the calculation of flutter critical wind speed, there are few simplified formulae proposed. In the Chinese code, the proposed method is still complex for the engineers. The results obtained from the Chinese code are close to buffeting theory. It can be expected because there are few simplifications in this method and the structural coupling are not significant in the example bridges. It should be mentioned that the simplified analysis is better used for the preliminary design. If the bridge is sensitive to wind, more precise analysis should be performed.