本文選題：橋梁工程 + 腐蝕��； 參考：《大連理工大學(xué)》2015年碩士論文

【摘要】：拉吊索腐蝕是橋梁設(shè)計和施工必須考慮的重要方面之一,特別是跨海大橋。目前,拉吊索所用材料大多數(shù)為高強碳素鋼絲或鋼絞線,材料在橋梁實際運營中長期處于高應(yīng)力狀態(tài),對外界環(huán)境侵蝕比較敏感。隨著橋梁使用年限的增長,拉吊索逐步暴露出防腐層老化、銹蝕、斷絲等問題,需要花費大量人力財力進(jìn)行更換,否則可能會導(dǎo)致索斷裂、引起橋梁垮塌等事故。為提高橋梁拉吊索的使用壽命,降低維護(hù)和更換成本,需要開發(fā)新型拉吊索材料。本文結(jié)合交通運輸部科技項目“全壽命不銹鋼鋼絲索開發(fā)研究”和國家基礎(chǔ)性項目(973項目)“特大跨橋梁安全性設(shè)計與評定的基礎(chǔ)理論研究”,對不銹鋼鋼絲的耐腐蝕性能進(jìn)行了研究,并對用不銹鋼鋼絲作橋梁拉索時的時變可靠度進(jìn)行了分析。本文主要內(nèi)容和結(jié)論如下：(1)對拉吊索腐蝕環(huán)境及腐蝕類型進(jìn)行了討論,分析了拉吊索各種類型腐蝕的機理及影響因素。(2)對零應(yīng)力的普通鍍鋅單根鋼絲及施加0、20%、30%和40%四個水平應(yīng)力的單根不銹鋼鋼絲,分7d、20d和40d進(jìn)行中性鹽霧試驗,測量鋼絲的質(zhì)量損失率,分析得到不同鋼絲的截面面積損失系數(shù)；研究了零應(yīng)力普通鍍鋅鋼絲和不同應(yīng)力水平下不銹鋼鋼絲的荷載-變形曲線,對拉伸后的鋼絲進(jìn)行了掃描電鏡分析。研究表明,零應(yīng)力下,普通鍍鋅鋼絲的重量損失率為不銹鋼鋼絲的30倍以上,不銹鋼鋼絲的防腐性能遠(yuǎn)好于普通鍍鋅鋼絲。不銹鋼鋼絲的重量損失率隨著施加應(yīng)力的增加而增加,高應(yīng)力下的不銹鋼鋼絲更容易腐蝕。短期內(nèi)腐蝕對鋼絲的極限強度影響不大；隨著腐蝕的增加,普通鍍鋅鋼絲和不銹鋼鋼絲的拉伸斷口呈現(xiàn)脆性增加的趨勢,普通鍍鋅鋼絲的斷口形貌由微裂紋向長寬裂紋發(fā)展,而不銹鋼鋼絲由于腐蝕程度較輕,只是出現(xiàn)了微裂紋。(3)利用ANSYS有限元建立了某斜拉橋的結(jié)構(gòu)分析模型,建立了橋梁在自重和隨機車輛荷載作用下的斜拉索索力概率模型,分別假定將本文研究的普通鍍鋅鋼絲和不銹鋼鋼絲作為橋的斜拉索,考慮本文試驗研究得到的截面面積損失系數(shù)建立斜拉索的功能函數(shù),采用一次二階矩方法計算得到了普通鍍鋅鋼絲拉索和不銹鋼鋼絲拉索的時變可靠指標(biāo)。分析表明,采用普通鍍鋅鋼絲時可靠指標(biāo)隨時間下降的速度較快,而采用不銹鋼鋼絲時可靠指標(biāo)隨時間下降的速度較慢。
[Abstract]:The cable corrosion is one of the most important aspects in bridge design and construction, especially the bridge across the sea. At present, most of the materials used in the slings are high strength carbon steel wire or steel strands. The materials are in high stress state for a long time in the actual operation of the bridge, and are sensitive to the external environment erosion. With the increase of the service life of the bridge, the problems of antiseptic layer aging, corrosion, broken wire and so on are exposed gradually, which need to be replaced with a large amount of manpower and financial resources. Otherwise, it may lead to the rupture of the cable and the collapse of the bridge. In order to improve the service life of bridge slings and reduce the cost of maintenance and replacement, it is necessary to develop a new type of sling material. In this paper, the basic theory research on safety design and evaluation of extra-large span bridges is combined with "Research on the development of stainless steel wire cables for the whole life" of the Ministry of Communications and Transport Science and Technology Project and the National basic Project "Yu973 Project". The corrosion resistance of stainless steel wire was studied, and the time-varying reliability of stainless steel wire as bridge cable was analyzed. The main contents and conclusions of this paper are as follows: (1) the corrosion environment and corrosion types of the slings are discussed. The corrosion mechanism of various types of slings and its influencing factors were analyzed. The neutral salt spray tests were carried out on ordinary galvanized single steel wire with zero stress and single stainless steel wire with 0 20% and 40% horizontal stress. The neutral salt spray test was carried out for 7 days, 20 days and 40 days, respectively. The mass loss rate of steel wire was measured, and the loss coefficient of cross section area of different steel wire was obtained, and the load-deformation curve of steel wire with zero stress, common galvanized steel wire and stainless steel wire under different stress levels was studied. The tensile steel wire was analyzed by SEM. The results show that the weight loss rate of common galvanized steel wire is more than 30 times of that of stainless steel wire under zero stress, and the corrosion resistance of stainless steel wire is much better than that of common galvanized steel wire. The weight loss rate of stainless steel wire increases with the increase of applied stress, and the stainless steel wire with high stress is more susceptible to corrosion. The short term corrosion has little effect on the ultimate strength of steel wire, with the increase of corrosion, the tensile fracture of common galvanized steel wire and stainless steel wire shows a tendency of increasing brittleness, and the fracture morphology of common galvanized steel wire develops from microcrack to long and wide crack. However, due to the mild corrosion degree of stainless steel wire, there is only a micro-crack. 3) the structural analysis model of a cable-stayed bridge is established by using ANSYS finite element method, and the probabilistic model of cable-stayed cable force of the bridge under the action of deadweight and random vehicle load is established. The conventional galvanized steel wire and stainless steel wire studied in this paper are assumed to be the stay cables of the bridge respectively. The function of the cable is established considering the loss coefficient of the cross-section area obtained by the experiments in this paper. The time-varying reliability indexes of common galvanized wire cables and stainless steel wire cables are calculated by the first-order second-order moment method. The results show that the reliability index decreases faster with time when common galvanized steel wire is used, while the reliability index decreases slowly with time with stainless steel wire.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：U443.38

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相關(guān)期刊論文 前1條

1 蔣湘軍;魏武;;基于蛇形機器人橋梁纜索無損檢測系統(tǒng)的研究[J];傳感器與微系統(tǒng);2011年04期

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本文編號：2041745