人行懸索支撐橋樑氣動力行為研究

Study of Aerodynamic Behavior of Cable-supported Pedestrian Bridges

陳怡儒(I-Ru Chen)

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(2013年)

https://doi.org/10.6846/TKU.2013.00935

摘要

在過去十年中，台灣以完成建造或正在施工的長跨徑人行橋梁不斷地增加。這類型的橋梁不僅僅只是為了滿足了交通運輸上的需求，還需要額外提供了娛樂、觀光以及美化環境上的功能，因此建築美學設計就成為了一項重要的環節，而斜張橋與吊索拱橋剛好滿足了這類型的需求。這篇論文的目的在於研究這些行人橋的氣動力行為反應。
在人行斜張橋方面以數值分析結構的動力特性，動力特性包含：自然頻率、模態振形。以跨徑與橋塔類型作為區分，在跨徑長度上選用100公尺到200公尺之間。而橋塔類型則選用三種不同的橋塔：單柱、A型、H型橋塔，探討動力特性上的關係，再進行數值分析顫振臨界風速和抖振反應。本文以兩種不同的橋面版進行模擬分析。
吊索拱橋方面則主要探討拱圈與主梁的相互影響，以相同主梁搭配不同大小拱圈以及單索面和雙索面進行動力分析，探討兩者之間的頻率、振態耦合的情形。
結果顯示，對於斜張橋，跨長和橋面版的寬深比對氣動力行為的影響相當明顯。而橋塔類型的影響是可以忽略不計。對於拱橋，拱和橋面之間的彎曲剛性的比例對氣動力行為是不可忽視的因素。

關鍵字

人行橋 ； 斜張橋 ； 吊索拱橋 ； 顫振 ； 抖振

並列摘要

The number of long-span pedestrian bridges completed or under construction has been increasing during the past decade in Taiwan. In addition to transportation needs, capabilities of recreation and sightseeing are also required for the design of this type of bridges. Therefore, esthetics is one of dominating factors in design. To meet the needs, cable-stayed bridges and arch bridges are often used. The objective of this thesis is to study the aerodynamic behavior of these pedestrian bridges.
For the cable-stayed bridges, a parametric analysis is performed to study the dynamic characteristics of the structures. The dynamic characteristics include natural frequencies and mode shapes of the vibration modes. The parameters studied here contain span lengths and types of towers. The main span lengths are ranged from 100 m to 200 m. Three types of towers are used: single column, A type and H type. Using the information obtained from the modal analysis, a numerical analysis is then conducted to investigate flutter wind speeds and buffeting responses of these bridges. Two types of bridge deck are studied in this analysis.
For the arch bridges, the parameters used in the analysis include deck width and flexural rigidity of arch. The structural coupling between arch and decks in the vibration modes is studied. Then the effects of coupled vibration modes on the flutter wind speed and buffeting responses of bridge decks is discussed.
The results show that the effects of span length and width-depth ratio of deck are significant in the aerodynamic behavior of cable-stayed bridges. The effects of tower types are negligible. For the arch bridges, the ratio of flexural rigidities between arch and bridge deck is an important factor for the aerodynamic behavior.

並列關鍵字

Pedestrian Bridge ； Cable-Stayed Bridge ； Arch Bridge ； Flutter ； Buffeting

參考文獻

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