本文關(guān)鍵詞： 可靠性評估 結(jié)構(gòu)耐久性 時變可靠度 剩余使用壽命 可靠指標(biāo)　出處：《蘭州交通大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著自然條件的不斷變化、經(jīng)濟(jì)發(fā)展帶來的交通流量及荷載等級的不斷增大，橋梁結(jié)構(gòu)正面臨著前所未有的考驗。在眾多因素共同作用下，隨著時間的推移，鋼筋混凝土橋梁結(jié)構(gòu)將會出現(xiàn)不同程度的損傷，這些損傷通常包括材料、構(gòu)件和結(jié)構(gòu)三個方面。各種損傷的不斷累積勢必會造成橋梁性能劣化、承載能力和耐久性下降的結(jié)果，最終影響其正常使用并造成安全隱患。如何科學(xué)合理地評估既有鋼筋混凝土橋梁的可靠性，并對其剩余使用壽命進(jìn)行預(yù)測，已成為目前國內(nèi)外橋梁學(xué)術(shù)界研究的重點問題之一。 通過開展對既有鋼筋混凝土橋梁結(jié)構(gòu)可靠性評估及使用壽命預(yù)測的研究，一方面可以指導(dǎo)橋梁的設(shè)計、施工和安全運(yùn)營；另一方面有助于盡早發(fā)現(xiàn)既有橋梁的潛在危機(jī)，，及時做出維修加固或拆除重建的決策。 本文以時變可靠度理論為依據(jù)，結(jié)合已有的材料耐久性的研究成果，從可靠性和使用壽命入手對既有鋼筋混凝土簡支梁橋進(jìn)行了研究分析，主要進(jìn)行了以下幾方面的內(nèi)容： 首先，就已有的對既有橋梁可靠性評估方法及研究現(xiàn)狀進(jìn)行了總結(jié)和特點評述，奠定了本文研究的理論基礎(chǔ)。 橋梁在實際運(yùn)營時，其抗力受很多不定因素的影響，并且它是一個隨時間衰減且不可恢復(fù)的過程，所以應(yīng)該將抗力視為一個隨機(jī)過程進(jìn)行處理。由此可知，橋梁結(jié)構(gòu)的可靠性評估應(yīng)是一個時變問題。本文借鑒了以前學(xué)者對抗力影響因素的研究成果，根據(jù)工程案例的實際背景建立了抗力計算模型、荷載概率時變模型及抗力衰減時變模型。 考慮抗力隨時間衰減問題，本文從混凝土碳化、鋼筋銹蝕、材料強(qiáng)度變化等方面入手，分析了其對抗力的影響。在進(jìn)行可靠指標(biāo)的計算時，我們首先需要將抗力隨機(jī)過程轉(zhuǎn)換為隨機(jī)變量的形式，并需要通過迭代進(jìn)行求解，因此本文利用MATLAB程序以輔助求解。 最后，通過工程實例，利用時變可靠指標(biāo)計算程序求出由8片T梁組成的20m長的鋼筋混凝土簡支梁橋?qū)?yīng)的時變可靠指標(biāo)，然后與目標(biāo)可靠指標(biāo)進(jìn)行比較求出了該橋的剩余使用壽命。
[Abstract]:With the continuous change of natural conditions and the increasing traffic flow and load grade brought by economic development, the bridge structure is facing an unprecedented test. The damage of reinforced concrete bridge structure usually includes three aspects: material, member and structure. The continuous accumulation of various damage will inevitably result in the deterioration of bridge performance, the decrease of bearing capacity and durability. How to scientifically and reasonably evaluate the reliability of existing reinforced concrete bridges and predict their remaining service life has become one of the key issues in the academic research of bridges at home and abroad. Through the research on reliability evaluation and service life prediction of existing reinforced concrete bridge structure, on the one hand, it can guide the design, construction and safe operation of the bridge; on the other hand, it can help to discover the potential crisis of the existing bridge as soon as possible. Make timely decision to repair, reinforce or dismantle and rebuild. Based on the theory of time-varying reliability and combined with the research results of material durability, this paper studies and analyzes the existing reinforced concrete simply supported beam bridge from the reliability and service life. The main contents are as follows:. Firstly, the existing reliability assessment methods and research status of existing bridges are summarized and reviewed, which lays the theoretical foundation of this paper. When the bridge is in operation, its resistance is affected by many uncertain factors, and it is a process of decay and irrecoverability over time, so the resistance should be treated as a random process. The reliability evaluation of bridge structure should be a time-varying problem. This paper draws lessons from the previous research results of the influence factors of the resistance force, and establishes the resistance calculation model according to the actual background of the engineering case. The load probability time-varying model and the resistance attenuation time-varying model. Considering the problem of resistance attenuation with time, this paper analyzes the influence of resistance force on concrete carbonization, steel bar corrosion, material strength change and so on. We first need to convert the resistance stochastic process to the form of random variable and to solve it by iteration. So we use MATLAB program to help solve the problem. Finally, through an engineering example, the time-varying reliability index corresponding to a 20m long reinforced concrete simply supported beam bridge composed of 8 T-beams is calculated by using the time-varying reliability index calculation program. Then compared with the target reliability index, the remaining service life of the bridge is obtained.
【學(xué)位授予單位】：蘭州交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U441;U445.7

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