https://scholars.lib.ntu.edu.tw/handle/123456789/80872
標題: | 以非破壞檢測進行鋼筋混凝土橋梁上部結構之安全評估(2/2) | 作者: | 劉佩玲 | 關鍵字: | 橋梁;鋼筋混凝土;安全評估;非破壞檢測;可靠度分析;bridge;reinforced concrete;safety assessment;nondestructive test;reliability. | 公開日期: | 31-七月-2003 | 出版社: | 臺北市:國立臺灣大學應用力學研究所 | 摘要: | 橋梁在陸地交通中一直是不可或缺的一環。一旦橋梁發生破壞, 不但會造成人命傷亡,而且當地交通頓時中斷,又缺乏替代路線,因 此後繼的損失更是不計其數。又加上橋梁造價昂貴,施工困難,因此 如何監測既有橋梁,使橋梁在設計年限內能安全有效地提供服務,一 直是各國道路工程主管單位努力的目標。 本計畫的主旨在提出一個可以對鋼筋混凝土橋梁上部結構進行安 全評估的方法。首先,以非破壞方法來檢測鋼筋混凝土橋梁,如混凝 土抗壓強度及鋼筋腐蝕,再以貝氏統計法來重建混凝土抗壓強度或鋼 筋面積的機率分佈,然後根據設計規範,對橋梁重做可靠度分析,看 橋梁是否還具有規範所規定的安全性。 本計畫將分別對T 型梁橋及箱型梁二種橋梁的安全評估進行研 究。作可靠度分析時,將考慮撓曲強度、剪力強度等不同破壞準則, 而系統中的不確定性,除了以非破壞檢測建立混凝土抗壓強度及鋼筋 面積之分佈,還將收集台灣地區的載重、道路鋪面等相關資料,使評 估方法更具有實用性。 Bridges play an indispensable role in land transportation. The collapse of a bridge often results in tremendous losses. Therefore, the safety assessment of bridges is an important and challenging task for civil engineers. The objective of this project is to develop a method to assess the reliability of the upper structures of reinforced concrete bridges. The safety of a bridge can be evaluated by means of reliability analysis. It provides a reasonable estimate on the failure probability of the bridge if the distributions of the uncertainties in the system are known. However, as the bridge is damaged, the compressive strength of concrete may decrease and corrosion of the steel reinforcement may occur. Apparently, the distributions of the material should be modified and the reliability of the bridge should be re-evaluated. It is proposed in this study that nondestructive tests be performed on the target bridge. Then, the Bayesian statistics is adopted to combine the original statistics with the NDT data to give a reasonable estimate of the current condition of the concrete and the reinforcement. As such, both the original data and the new observations play equally important roles. Finally, reliability analysis is performed on the target bridge using the updated distributions of the concrete and steel reinforcement. The limit-state function is formulated based on the design specifications. As such, the reliability index of the bridge is comparable to the design value. Both the T-beam bridge and the box girder bridge will be considered in this study. In order to apply the proposed method to local bridges, this study will also collect statistics regarding the dynamic load and pavement in Taiwan. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/21668 | 其他識別: | 912211E002072 | Rights: | 國立臺灣大學應用力學研究所 |
顯示於: | 應用力學研究所 |
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912211E002072.pdf | 966.83 kB | Adobe PDF | 檢視/開啟 |
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