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標題: 斜張橋之抗風設計與風洞試驗
The Wind-Resistant Design and Wind Tunnel Tests of a Cable Stayed Bridge
作者: 顏召宜
Yen, Jawyi
關鍵字: cable stayed bridge
wind tunnel
出版社: 土木工程學系
摘要: 近年來,由於砂石的過量開採,台灣西部河川河床下降,造成橋墩裸露,嚴重危及傳統短跨徑橋梁的安全。長跨徑斜張橋的發展適可解決這個問題。然而,斜張橋細長而柔軟的特性,卻增加了對風力引發振動的敏感性。工程師尤其關切其顫振風速、抖振反應以及纜索的馳振現象。 斜張橋的抗風設計與分析,首先在於瞭解橋址的風場特性、詳細的風力資料以及紊流的效應,將決定的設計風力導入結構計算及風洞試驗。本文即藉由國內數座斜張橋的抗風設計,研究其橋址風場風力之計算,各階段抗風設計方法與程序。同時探討了斜張橋受風力作用下的各種氣彈力行為,提供消減振動現象的解決對策;再藉由運動方程式的建立,以三維分析的方法,求得較合理之斜張橋振動臨界風速;並介紹各種模型風洞試驗設施及試驗方法。 最後對主要反應顫振現象、渦流振動及抖振現象,以跨越旱溪之拱承式斜張橋為例進行節段模型風洞試驗,風力由平滑流變化至紊流,以各種不同的風向攻角,評估橋梁斷面受風力之行為,確保橋梁之抗風性及安全性。
As the safety of the traditional short-span bridges are threatened by the reducing bed elevation of the rivers crossing the west island of Taiwan in the recent decade. The development of cable-stayed bridges, therefore, is one of the solutions to this problem. These long span and slender section bridges were found to be more flexible and sensitivity to wind excitation. Especially the flutter and the buffeting responses are the major concerns for the bridge engineers. Detailed information on wind around the bridge site is important in determining the wind speed for design and the conducted wind tunnel tests. In this study, all aspects of wind design and different models of wind tunnel tests are discussed. The aero-elastic phenomenon coming from aerodynamics of cable-stayed bridges are introduced as well. A three-dimensional analysis for critical wind speed which results in the initiation of a flutter and buffeting motions of a cable-stayed bridge will lead to a more reasonable result. Section model test of Han Hsi Cable-Stayed Bridge are conducted to describe the flutter wind speed and the vortex shedding responses under smooth and turbulent flow. The results show, in service condition, the bridge will be safe for flutter under the design wind speed. And the vortex induced shedding can be neglected under turbulent flow.
Appears in Collections:土木工程學系所



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