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題名 | 臺中市旱溪東門橋桃芝颱洪橋基塌陷之成因探討=Study on the Cause of Damage to the Collapsed Dong--Men Bridge |
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作者姓名(中文) | 林呈; 李秉融; | 書刊名 | 臺灣公路工程 |
卷期 | 29:8 2003.02[民92.02] |
頁次 | 頁2-34 |
分類號 | 441.815 |
關鍵詞 | 束縮沖刷; 局部沖刷; 水流攻角; 低水護岸; 馬蹄渦; Contraction scour; Local scour; Angle of attack; Low-water revetment; Horseshoe vortex; |
語文 | 中文(Chinese) |
中文摘要 | 本文旨在探討民國90年7月30日桃芝颱洪造成臺中市區內跨越旱溪之東門橋受創的成因,首先藉由災後現場的調查測量與已沉陷橋基之周邊河床的開挖工作來了解其基礎型式及受災情形,其次經由水工模型實驗探討水流攻角在橋墩尾端所造成局部沖刷坑之影響,基於上述之調查與實驗,此次災害的成因分為:束縮沖刷與局部沖刷(尤其是水流攻角所造成的效應)等二個部份。此外本文也引用一般常用的沖刷經驗公式將之應用於此次災況之沖刷深度估算,並由現場調查、開挖河床的成果,從中反算這些經驗公式的準確性及適用性,以作為將來估算河床沖刷量的本土化之參考案例之一,並可作為工程設計的基本資料,進而達到防災、減災的目的。 |
英文摘要 | Dong-Men bridge crossing the Han River in Taichung City was seriously damaged by torrential flood during the passage of Typhoon Toraji on July 30, 2001. The aim of the present study is to explore the cause of damage to this bridge. Methods used in this study include literature review, aerial photos, site in investigation and surveying, excavation of river-bed around the collapsed foundation, and simplified hydraulic model test performed in water channel. It is found that the causes of damage can be mainly attributable to contraction scour and local scour. The former one was resulted from the construction of low-water revetments which occupies some portion of the flow width, thus leading to increase of flow velocity at the inlet of constriction. The latter one was caused by the action of horseshoe vortex flow around the bridge pier, which maybe significantly scoured as the angle of attack (between the flow direction and the longitudinal alignment of bridge pier) gets larger. Moreover, some empirical formulas were used with given hydraulic conditions to estimate the depth of local scour. These corresponding results were then compared with the practical scour depth which was calculated by excavation of river-bed and actual subsidence of bridge pier. The feasibility of these empirical formulas was then verified and evaluated, aiming to find out some gudies applicable in Taiwan. |
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