橋梁耐洪風險評估決策模式之研究

The Decision Model of Flood-Resistance Risk Assessment for Bridge

劉絹絹(Chuan-Chuan Liu)

指導教授 ： 李有豐

國立臺北科技大學/工程學院/土木與防災研究所/碩士(2010年)

https://doi.org/10.6841/NTUT.2010.00059

摘要

臺灣地區橋梁於921大地震、331大地震後，山坡地土質鬆軟，加上全球氣候暖化及聖嬰現象，造成氣候異常發生豪大雨機會增加。每遇豪大雨即造成山區發生超大洪水及土石流，沖刷河道上橋梁，外加臺灣地區的河川，受早期開放採砂及長期盜砂的影響，河川環境極不穩定，橋梁受沖刷情形愈來愈嚴重。
本研究首先蒐集國內對河川橋梁沖刷相關文獻，對橋梁受洪水沖刷時，影響橋梁安全的危害度的因子進行統整，並區分為橋梁環境影響程度指標及橋梁耐洪能力危害度指標，確認評估指標項目，完成本研究之評估目標及層級架構。再以層級分析法透過專家問卷方式進行各指標項目之權重，權重決定後與指標項目內容評分分數相乘，即得各指標分數。以橋梁環境影響程度指標為縱軸，橋梁耐洪能力危害度指標為橫軸，得到橋梁耐洪風險評估矩陣圖，即完成本研究之橋梁耐洪風險評估決策模式。
橋梁耐洪風險評估決策模式建立後，蒐集國內北部、中部、南部河系上橋梁基本資料、河川水文資料及評估資料進行案例分析，得各橋梁之風險等級及颱風豪大雨時之風險排序，評估結果再與橋梁主管機關之養護橋梁工程司進行排序之比較，依本研究之風險評估排序皆與專家依據現場經驗判斷之排序相符。
暨有公路橋梁耐洪初評項目係將環境影響程度與橋梁耐洪能力危害度合併評估，本研究將環境影響程度與橋梁耐洪能力危害度分開評估，可得到較精確結果，提供橋梁主管機關於颱風豪大雨前，對轄管橋梁進行橋梁耐洪風險評估，排序橋梁危險之優先順序。

關鍵字

層級分析法 ； 風險評估 ； 風險矩陣圖

並列摘要

After the 921 earthquake and the 331 earthquake,the soil texture of hilly land in Taiwan has become soft and loose. Besides the global warming,the E.L Nino increase the opportunities of heavy rainfall which results in flooding and mudslides in the mountain areas. For decades,both the legal or illegal gravel mining has deteriorated the foundations of bridges over the rivers. Bridge scour the situation is getting worse by the floods.
This research collects information relative to bridge scouring, and summarizes the factors of bridge safety. There are two different indexes which will be used in this research, the first is the index of bridg environment hazard; while the second is the index of bridge flood-resistance hazard.After setting the targets and items, to decide the assessment and hierarchy of this research. The Analytic Hierarchy Process will be used to determine the weights of criteria items, then multiply the items weights and the items score to obtain the criteria score. The vertical axis is the criteria for the bridge environment hazard, while the and horizontal axis is the criteria for the bridge flood-resistance hazard to obtain matrix diagrams of flood -resistance risk assessment for bridge and the decision model of flood-resistance risk assessment for bridges.
After forming the decision model of flood-resistance risk assessment for bridges. Research requires the collection of bridge’s basic data, river hydrological data and assessment data for the river system of the North and middle and South of Taiwan. Risk categories were categorized form least dangerous to most dangerous, then evaluated and compared with the risk category levels provided by the appropriate bridge authorities. Comparisous showed that the assessed risk levels of varying risk categories were fairly similar between this research and the authorities ratings.
Originaly flood-resistance preliminary risk items of bridges environmental hazards and flood-resistance hazards. In this research however, consisted of bath environmental hazards and flood-resistance hazards are separately assessed to obtain more accurate results.This is to provide to appropriate authorities of bridge so that flood-resistance risk assessment and risk ranking of the bridge can be made before the Typhoons strike.

並列關鍵字

Analytic Hierarchy Process ； Risk Assessment ； Risk Matrix Diagrams

參考文獻

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