施工階段斜張橋結構非線性分析

Nonlinear Analysis of Cable-Stayed Bridges During Erection Stages

唐子揚(Tzu-Yang Tang)

指導教授 ： 王寶璽

中原大學/工學院/土木工程研究所/碩士(2002年)

https://doi.org/10.6840/cycu200200142

摘要

本文應用有限元素法建立斜張橋逐段施工各階段結構靜、動態分析模式及相關電算程式。依照橋樑實際施工順序建立正算法與倒拆法兩種分析方法，用以進行施工階段結構分析。前者依照施工程序正向演算分析，由獨立橋塔開始，逐段分析至成橋階段為止；後者則依施工程序反向分析，由成橋開始逐段拆卸樑段及纜索至獨立橋塔為止，尋求各施工階段橋樑結構之幾何位置及索力分佈，並進一步對每一施工階段結構進行動態之頻率、振態分析。本文取二個斜張橋為例，考慮不同之單、雙懸臂工法施工，分別應用正算法與倒拆法進行逐段施工各階段結構靜態分析，並經由動態之頻率、振態分析，了解斜張橋各階段結構體之基本靜、動力特性。文中考慮非線性樑柱效應及纜索中垂效應之影響，並與線性分析結果進行比較。由數值分析結果可得，應用本文所建立之分析理論與電算程式可全自動分析斜張橋結構在各施工階段之理想位置（主要指橋面標高）及理想應力狀態（主要指纜索拉力），提供斜張橋在施工階段大樑新節塊拼裝前後，橋面標高及纜索索力之上下限值，可作為斜張橋設計及施工時之參考依據。使用雙懸臂工法施工時，整體結構之自然振動頻率隨著施工階段數增大而降低，直到主樑合攏前一個施工階段，結構體之最小基本頻率達到最低點，此施工階段應為動態分析時，最須注意的狀態。樑柱效應及纜索中垂效應會引起構件元素勁度衰減，導致結構整體勁度降低，使得斜張橋結構變得較為柔軟，易生較大的變位，自然頻率值較線性分析值為低，但振動模態不變。

關鍵字

斜張橋 ； 施工階段分析 ； 正算法 ； 倒拆法

並列摘要

The aim of this study concerns with the analysis of cable-stayed bridges at different erection stages during construction. A finite element computation procedure is set up for the nonlinear analysis of such kind of structures during erection procedures. Two computational processes are established, one is a forward process analysis and the other is a backward process analysis. The former is performed by following the sequence of erection stages in bridge construction and the latter is carried out in the inverse direction of erection procedures. Both of them can be successfully applied for the analysis of cabled-stayed bridges during erection stages. The structural behavior of cable-stayed bridges at different erection stages has been examined detailedly, such as the pretension required in cable-stays and the corresponding structural configurations of the bridge etc. Through proper controls at each erection stage based on the analysis data obtained, the designed initial shape (pretension in cables and configuration of girders) of cable-stayed bridges can be achieved and constructed.

並列關鍵字

cable-stayed bridge ； forward process analysis ； backward process analysis

參考文獻

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