基礎裸露橋梁耐震能力評估

陳彥豪(Yen-Hao Chen)

指導教授 ： 蔡益超

國立臺灣大學/工學院/土木工程學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.00735

摘要

我國橋梁因為受到沖刷，基礎裸露的問題嚴重，但並沒有針對此問題有完整的分析方法與範例供工程師參考，因此，本研究以橋梁耐震設計規範草案中之靜力分析法設計出的橋梁為模型，並包含基礎部分一併利用容量震譜法進行耐震能力的評估。根據橋梁斷面之強度與韌性，決定破壞模式，並輸入對應的塑鉸關係。透過正確的假設，才能準確的模擬橋梁受到外力時的行為。
橋梁結構之容量譜曲線是由其容量曲線轉換而來，而結構之容量曲線透過非線性靜力分析（Pushover Analysis）方可求得。本研究針對橋梁沖刷後分析的流程提出一些建議，並依據三種破壞模式，即韌性充分發揮之彎矩破壞、韌性未充分發揮前之剪力破壞以及剪力破壞，來設定塑鉸特性。本研究除了根據強度與韌性推估耐震能力外，還有考慮到穩定性，而分析的橋梁包含了基樁與沉箱的單柱式橋墩，以及兩座均屬四柱三跨的樁基礎橋梁；一為各跨間均有伸縮縫，另為具鉸接橋面版橋梁。最後，再做一座橋面版連續的沉箱基礎橋梁的行車向分析。

關鍵字

橋梁 ； 基礎裸露 ； 非線性靜力分析 ； 塑鉸

並列摘要

Foundations exposed of bridges due to the scour are serious problems in Taiwan. These problems, however, have no effective solutions that engineers can follow. Therefore, the present study intends to bring up a process using the capacity spectrum analysis to determine their aseismatic capabilities. To model accurately the behavior of the bridge needs the assumptions according to determine the failure type of members sections based on strength and ductility, and set up the corresponding hinge properties.
This study establishes the capacity curve of the bridge by carrying out pushover analysis, and derives the corresponding capacity spectrum. The aseismatic behavior define as the ground acceleration corresponding of the performance point. We concern about the strength, ductility and stability in the procedure for analyzing the uncovered foundations, and setting hinge properties bases on three failure types, flexible failure after ductility exhausted, shear failure before ductility exhausted, and shear failure without ductility.
The analytical cases including single column with pile or caisson foundations, which are typical types in Taiwan, and two bridges, one is three spans simply support, the other is three spans deck continuous.

並列關鍵字

bridge ； exposed foundation ； pushover analysis ； hinge

參考文獻

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參考文獻