本文關(guān)鍵詞：損傷拉索剩余壽命預(yù)測模型與破損安全評價(jià)方法研究　出處：《重慶交通大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 拉索 腐蝕因子 損傷 剩余壽命 安全評估

【摘要】：斜拉橋由于其具有的結(jié)構(gòu)自重輕,跨越能力得到提高,施工更加便捷；橋墩少,受船只撞擊的幾率小,通航寬度大,通航能力強(qiáng)；結(jié)構(gòu)的橫向剛度大,抗風(fēng)能力強(qiáng)；造型美觀等優(yōu)點(diǎn),在20世紀(jì)得到飛速的發(fā)展。拉索,作為斜拉橋的最主要承重傳力構(gòu)件,由于其結(jié)構(gòu)尺寸相對較小,使其成為斜拉橋結(jié)構(gòu)體系中最容易受到損傷的構(gòu)件之一,且對病害的敏感程度較高。據(jù)統(tǒng)計(jì),現(xiàn)階段出現(xiàn)的斜拉橋病害中,出現(xiàn)在拉索的各種病害占了絕大部分。這些病害使拉索的力學(xué)性能下降,銹蝕加快,耐久性降低。因此對損傷拉索的研究對斜拉橋發(fā)展與安全運(yùn)營具有十分重大意義。在本文中,研究了拉索的腐蝕機(jī)理,外界環(huán)境對拉索的腐蝕速率產(chǎn)生影響的機(jī)理,環(huán)境中哪些因素對拉索腐蝕速率的影響大。根據(jù)電化學(xué)原理和正交實(shí)驗(yàn)原理設(shè)計(jì)電化學(xué)的試驗(yàn)方案,研究了在外界溫度、氯鹽的含量、PH值以及他們之間的兩兩的交互作用對高強(qiáng)度鋼絲腐蝕的影響,分析了高強(qiáng)度鋼絲的腐蝕速率和外界環(huán)境腐蝕因子之間的函數(shù)關(guān)系。為了研究拉索的腐蝕,建立了一個腐蝕因子的擴(kuò)散模型,當(dāng)拉索護(hù)套破損后,分析了外界環(huán)境中的腐蝕因子沿著護(hù)套破損處往拉索內(nèi)部擴(kuò)散的機(jī)理。擴(kuò)散模型根據(jù)菲克定律和實(shí)際情況建立數(shù)學(xué)物理方程,擬定邊界條件和初始條件,解出此數(shù)學(xué)物理方程,得出時間和位置與腐蝕因子濃度之間的函數(shù)關(guān)系。在得出拉索內(nèi)部高強(qiáng)度鋼絲周圍的腐蝕因子濃度后,再根據(jù)不同腐蝕因子濃度與鋼絲的腐蝕速率之間的函數(shù)關(guān)系,最后得到了高強(qiáng)度鋼絲及拉索的腐蝕量。在經(jīng)過嚴(yán)密的理論推導(dǎo)、數(shù)學(xué)計(jì)算后,最終得到了計(jì)算拉索腐蝕量的方法,推導(dǎo)出了拉索力學(xué)性能退化程度,對拉索的承載能力重新進(jìn)行了評估。在此基礎(chǔ)上提出了拉索安全評定的三大判據(jù),即承載能力判定依據(jù),腐蝕量判定依據(jù)和斷絲率判定依據(jù)。依據(jù)規(guī)范把拉索分成了五個等級,并以此來評估拉索的安全性。根據(jù)拉索的腐蝕全過程,和拉索的安全判定依據(jù),提出了預(yù)測拉索的壽命具體流程和方法,從而為確定拉索的更換時間提供了理論依據(jù)。
[Abstract]:The cable-stayed bridge is more convenient to be constructed because of its light structure weight and improved span capacity. The bridge pier is few, the probability of being hit by the ship is small, the navigation width is large, the navigation ability is strong; The transverse stiffness of the structure is large and the wind resistance is strong; In 20th century, the cable, as the main load-carrying component of cable-stayed bridge, was developed rapidly in 20th century because of its relatively small structure size. It is one of the most vulnerable components in the cable-stayed bridge structure system, and the sensitivity to the disease is high. According to statistics, in the current stage of cable-stayed bridge diseases. Most of the diseases appear in the cable. These diseases decrease the mechanical properties of the cable and accelerate the corrosion. Therefore, the study of damaged cables is of great significance to the development and safe operation of cable-stayed bridges. In this paper, the corrosion mechanism of cables is studied. The influence of external environment on the corrosion rate of cables, and which factors in the environment have a great effect on the corrosion rate of cables. According to the principle of electrochemistry and orthogonal experiment, the experimental scheme of electrochemistry is designed. The effects of external temperature, pH value of chloride salt and the interaction between them on the corrosion of high strength steel wire were studied. The functional relationship between corrosion rate of high strength steel wire and external environmental corrosion factor was analyzed. In order to study the corrosion of cable, a diffusion model of corrosion factor was established, when the sheath of cable was damaged. The diffusion mechanism of corrosion factors in the external environment along the damaged sheath to the cable is analyzed. The diffusion model establishes the mathematical and physical equations according to Fick's law and the actual conditions, and draws up the boundary conditions and initial conditions. The mathematical and physical equation is solved, and the functional relationship between the time and position and the concentration of corrosion factor is obtained, and the concentration of corrosion factor around the high strength steel wire inside the cable is obtained. Then according to the function relationship between the different concentration of corrosion factor and the corrosion rate of steel wire, the corrosion quantity of high strength steel wire and cable is obtained. Finally, the method of calculating cable corrosion is obtained, the degree of degradation of cable mechanical properties is deduced, and the load-carrying capacity of cable is re-evaluated. On this basis, three criteria for cable safety evaluation are proposed. According to the criterion, the cable is divided into five grades, and the safety of the cable is evaluated. According to the corrosion process of the cable, the whole process of cable corrosion is evaluated. The concrete flow and method of predicting the life of cables are put forward, which provides a theoretical basis for determining the replacement time of cables.
【學(xué)位授予單位】：重慶交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：U446

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本文編號：1398306