斜拉索振動對斜張橋結構行為之影響

Influence of Cable Vibration on Cable-Stayed Bridges

陳威中(Wei-Chung Chen)

指導教授 ： 王寶璽

中原大學/工學院/土木工程研究所/碩士(2004年)

https://doi.org/10.6840/cycu200400448

摘要

摘 要

本文應用有限元素法建立斜張橋結構非線性動態分析模式，藉電子計算機模擬分析，探討斜拉索自身振動現象及其對斜張橋結構動態行為之影響。一般斜張橋結構分析多半將斜拉索簡化為單一纜索元素，如同將其視為只具軸向伸縮桿件，分析時無法將纜索橫向振動效應納入考慮。鑒於此，本文將斜拉索視為多個纜索元素組成，將索身橫向振動納入考慮，得到較真實的結構動態行為，重點著重於考慮斜拉纜索振動對斜張橋整體結構行為之影響。本文以三個斜張橋為例，分別將斜拉索以單一纜索元素與多個纜索元素近似模擬，進行分析並比較其差異。由分析結果顯示，以多個纜索元素模擬斜拉索時，在初形分析中，可以得到較接近真實的形狀；頻率分析時，能夠得到全部的振態，其中包含了斜索本身的纜索振態，因此將斜拉索細分，可得到更接近真實的情形；在變形分析中，斜拉索有無細分，結果差異很小，因此，在靜力變形分析時，以單一纜索元素藉助等效纜索彈性係數近似模擬斜拉索即可，可簡化運算；在動力分析分面，兩者所得結果均很相近。線性與非線性動力反應分析所得結果亦相近，惟仍有部分位移反應相差頗大。

關鍵字

斜張橋 ； 斜拉索 ； 振動

並列摘要

Abstract

The aim of this study concerns with the dynamic analysis of cable-stayed bridges including the vibration effect of cable stays. A finite element computation procedure will be set up for the nonlinear dynamic analysis of such kind of structures. The dynamic structural behaviors of cable-stayed bridges influenced by the cable vibration will be examined detailedly, such as the natural frequencies and modes and the dynamic responses will be examined. Three different types of cable-stayed bridges are taken and two cases are considered. In case 1 one single element per cable stay is used and six elements per cable stay is used in case 2 The results show that when six elements per cable stay are used, one can find the real shape in initial shape analysis and all the natural frequencies and modes in frequency analysis. In the static deflection analysis, both of two cases offer the same results, that means one single element per cable stay can be well used in static analysis that can simplify the computation. The dynamic responses analysis have the similar results for the each case. No great difference between the results determined by linear and nonlinear dynamic analysis, but there are difference in some displacement responses existing.

並列關鍵字

cable stays ； cable-stayed bridge ； vibration

參考文獻

54. 鄭厚農，“斜張橋施工階段地震分析”，私立中原大學土木工程研究所，碩士學位論文，臺灣省，中壢市，民國92年12月

57. 唐子揚，“施工階段斜張橋結構非線性分析”，私立中原大學土木工程研究所，碩士學位論文，臺灣省，中壢市，民國91年6月

1. Au, F.T.K., Cheng, Y.S., Cheung, Y.K. and Zheng, D.Y., “On the determination of natrral frequencies and mode shapes of cable-stayed bridges”, Applied Mathematical Modelling 25, pp.1099-1115, 2001

2. Billington, D. and Nazmy, A. “History and Aesthetics of Cable-Stayed Bridges”, J. of Str. Engg., ASCE, Vol. 117, No. 10, pp.3101-3134, 1990

4. Chen, D.W., Au, F.T.K., Tham, L.G. and Lee, P.K.K., “Determination of Initial Cable Forces in Prestressed Concrete Cable-Stayed Bridges for Given Deck Profiles Using The Force Equilibrium Method”, Int. J. of Computers & Structures, Vol. 74, pp.1-9, 2000