斜張橋影響線分析之研究

斜張橋為一高度靜不定的橋梁結構，纜索的中垂效應、主梁及橋塔的梁柱效應、整體結構的幾何大變形效應，以及材料的非線性效應，更增添斜張橋結構分析上的困難度。在橋梁結構分析時，一般需藉由影響線來確定活載重的臨界位置，進而得出斷面最大應力值，以作為斷面設計之依據，因此如何針對非線性與高靜不定度的斜張橋進行影響線分析，便成為一項值得探討的研究課題。本文即針對此項課題進行模式建立與分析比較。文內，除探討建立斜張橋之影響線分析模式外，並探討比較纜索材質改變及纜索、橋塔、主梁等結構之彈性模數變化以及在兩邊跨不同位置設置輔助墩對斜張橋影響線分析結果之影響。研究結果顯示，增設輔助墩可使主梁的垂直位移減少很多；改採碳纖維索可使主梁承受之軸力減少，但會增加主梁的垂直位移與彎矩；纜索彈性模數的變化對斜張橋影響線分析結果之影響最大。

關鍵字

斜張橋；影響線；彈性模數；輔助墩；碳纖維索

並列摘要

Cable-stayed bridge is a structure with high redundancies. Much nonlinearity such as cable-sag, beam-column, large-displacement and material-nonlinearity effects increase much difficulty to the structural analysis of the cable-stayed bridges. In the structural analysis of bridges, the critical location of live load is generally determined by the influence line. Then, the maximum stress of each section will be determined and will be used to design each section. Therefore the study of influence analysis of the cable-stayed bridges with much nonlinearity and high redundancies will be a good topic for studying in advance. The objective of this paper is to establish an analytic model and investigate this topic in advance. In addition, the effect of using the carbon fiber composite cables, changing the elastic modulus of cables, tower and main girder, and installing the assistant piers on the influence line analysis results were also investigated in this paper. The results have shown that the vertical displacement of main girder decreased quite much after installing the assistant piers. The axial force of main girder also decreased after using carbon fiber composite cables, but its vertical displacement and bending moment increased. The maximum effect on the influence line analysis results of cable-stayed bridges was the changing of elastic modulus of cables.

並列關鍵字

cable-stayed bridge ； influence line ； elastic modulus ； assistant pier ； carbon fiber composite cable

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斜張橋影響線分析之研究

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