人行拱橋的顫振分析

Flutter Analysis of Pedestrian Arch Bridges

趙祚萱(Sheanne Chao)

指導教授 ： 林堉溢

淡江大學/工學院/土木工程學系碩士班/碩士(2014年)

https://doi.org/10.6846/TKU.2014.01137

摘要

一般而言，大垮度拱橋是作為人行天橋良好的選擇。這是因為橋樑的型態，不僅能滿足運輸需求，也可能成為當地的標誌性建築。在這些人行天橋中，因為橋面版較為狹窄，故單拱是唯一的選擇。由於單拱缺乏側向支撐，並由於橋跨距長度的高度增加，橋拱的拖曳向反應較為顯著，不能忽略。基於顫振理論、抖振理論及斷面模型試驗測得的顫振導數，將作用在拱圈上的風力放入運動方程式進行顫振和抖振分析的推導。如此一來，預測出來的空氣動力學反應對於橋梁的初步設計很有幫助。

本文採用人行吊索拱橋作為例題，來證明這種方法的有效性和適用性。從數值模擬結果，作用在橋上的顫振風速的拱上的力的影響進行討論。該結果表明，作用在拱圈的風力將增加整個拱橋的顫振臨界風速。

關鍵字

人行拱橋 ； 顫振 ； 抖振 ； 斷面模型實驗

並列摘要

The long-span arch bridges have been a favorable choice for the design of pedestrian bridges during the past decades in Taiwan. This is because the type of bridges not only can satisfy the transportation needs but also may become the landmark in the local area. In these pedestrian bridges, a single arch is the only choice due to the narrow bridge deck. Since the single arch lacks lateral support and its height increases with the bridge span length, the drag responses in the arch become significant and cannot be negligible. An analytical approach based on flutter and buffeting theory associated with the information measured from section model tests is presented in this thesis. The wind forces action on the arch are incorporated into the derivation of the multi-mode equations for flutter and buffeting analysis. Using this approach, the predicted aerodynamic responses can be obtained and may be helpful for the preliminary design.
An arch bridge with a straight bridge girder is used as an example to demonstrate the validity and applicability of this approach. From the numerical results, the effects of the forces acting on the arch on the flutter wind speed of the bridge are discussed. The results show that the addition of wind forces acting on the arch will increase the flutter wind speed of the whole bridge.

並列關鍵字

Pedestrian arch bridge ； Flutter ； Buffeting ； Section Model Test

參考文獻

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