不同系列橋樑斷面之氣動力參數研究

Study of Aerodynamic Coefficients for Different Types of Bridge Deck Sections

趙偉棠(Wei-Tang 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(2007年)

https://doi.org/10.6846/TKU.2007.00337

摘要

本論文的研究內容為不同系列斷面對長跨徑橋梁顫振與抖振行為之 探討，選用每一系列不同寬深比的斷面進行斷面模型風洞實驗，求得顫振 導數及風力係數。本研究選用四種主要的斷面形式，分別為矩形斷面、削 角斷面、箱型斷面與ㄇ型斷面。其中矩形斷面為主要實驗之項目，而削角 斷面、箱型斷面及ㄇ型斷面的資料則是使用他人研究結果，再以風力係數 以及顫振導數代入數值分析求取原橋的顫振臨界風速和抖振反應。 由本文研究之結果顯示，在大約相同寬深比下，就實驗值而言，削角 幾何形狀為穩定性最佳的斷面，其次為平板斷面，箱型斷面為第三，而最 不穩定的則是ㄇ型斷面。平滑流場下使用數值橋樑模型分析顫振臨界風速 結果則與實驗值相符合，而紊流場中，其不同系列斷面的穩定性也與實驗 值相符，隨著紊流強度的增加，其顫振現象也隨之延後。因此在相同寬深 比下，橋樑斷面幾何形狀的改變對於氣動力穩定亦為橋樑設計考量時的關 鍵。

關鍵字

長跨徑斜張橋 ； 寬深比 ； 斷面模型 ； 相似性轉換 ； 抖振反應 ； 渦流振動 ； 顫振臨界風速

並列摘要

This main objective of this thesis is to investigate and compare flutter
wind speeds and buffeting responses of the prototype bridge with different
types of deck sections. There are four series of bridge decks including
rectangular sections, rectangular sections with triangular edge-fairings, box
sections and plate girder sections. In each series several section models with
different width-depth ratios are studied. Only the tests of the series of
rectangular sections are conducted in this thesis. The other three types are
adopted from other researchers’ work. The static wind force coefficients and
the flutter derivatives are measured in the tests and then substituted into the
numerical model to evaluate the flutter wind speed and buffeting response of
the prototype bridge.
The comparison of the flutter wind speeds obtained from the tests
indicates that for a given width-depth ratio, the rectangular section with
triangular edge-fairings is the best, rectangular section the second, box section
the third, and plate girder section the worst. The flutter wind speed obtained
from a numerical analysis based on flutter derivatives agrees well with that
measured from the test. The results from the tests in turbulent flows indicate
that the flutter wind speed increases with turbulence intensity. The results
reveals that the modification of the bridge deck section significantly affect the
aerodynamic stability of bridges.

並列關鍵字

long-span bridge ； width-to-depth ratio (B/D) ； deck section model ； buffeting ； better-streamlined ； flutter wind speed ； vortex shedding

參考文獻

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6. Saito, T., Shiraishi, N. and Ishizaki, H., “On Aerodynamic stability of double-decked / trussed girder for cable-stayed “Higashi-Kobe Bridge” ,”Journal of Wind Engineering and Industrial Aerodynamics, Vol 33, pp. 323-332 (1990).

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