本文選題：大跨度鋼斜拉橋 + 系統(tǒng)可靠性　； 參考：《西南交通大學(xué)》2015年博士論文

【摘要】：隨著近年來斜拉橋不斷向大跨度方向蓬勃發(fā)展,其結(jié)構(gòu)形式日趨表現(xiàn)出大型化、復(fù)雜化以及纖柔化的特點(diǎn)。大跨度鋼斜拉橋在規(guī)模尺度上的超越對(duì)結(jié)構(gòu)的整體安全性能提出了更大的挑戰(zhàn),其施工及運(yùn)營(yíng)期的系統(tǒng)可靠性問題也更為突出。本文針對(duì)既有系統(tǒng)可靠度研究在理論方法以及實(shí)踐分析等方面的固有困難,從系統(tǒng)極限狀態(tài)曲面概念出發(fā),將支持向量分類算法(SVC)和LHS抽樣遷移策略等方法引入了系統(tǒng)可靠度理論的研究,并針對(duì)既有可靠度指標(biāo)算法缺陷進(jìn)行了改進(jìn)與修正,進(jìn)一步完善了系統(tǒng)可靠度的理論方法。在此基礎(chǔ)上,基于所獲取的變量統(tǒng)計(jì)概率模型,對(duì)大跨度鋼斜拉橋施工及運(yùn)營(yíng)期的系統(tǒng)可靠性演化規(guī)律及特點(diǎn)進(jìn)行了深入研究和探討。所完成的研究工作主要包括以下五個(gè)方面：1.結(jié)構(gòu)可靠度指標(biāo)計(jì)算方法的進(jìn)一步研究。針對(duì)傳統(tǒng)結(jié)構(gòu)可靠度指標(biāo)算法在收斂性以及計(jì)算效率上的固有缺陷,從理論原理和工程應(yīng)用角度出發(fā),在厘清問題本質(zhì)來源的基礎(chǔ)上,首先基于方向修正原理提出了計(jì)算結(jié)構(gòu)一次二階矩可靠度指標(biāo)的方向修正算法。然后通過理論推導(dǎo)和幾何分析,對(duì)線抽樣Monte Carlo法進(jìn)行了修正改進(jìn),使其適用性得到拓展提高。最后通過數(shù)值抽樣以及回歸分析方法對(duì)改進(jìn)的功能函數(shù)二階展開形式進(jìn)行了系統(tǒng)研究,建立了基于非線性回歸分析預(yù)測(cè)算法的二次二階矩可靠度指標(biāo)計(jì)算方法。并基于代表性數(shù)值算例驗(yàn)證了所提出方法的有效性和優(yōu)越性。2.基于SVC抽樣遷移的系統(tǒng)可靠度理論算法研究。針對(duì)傳統(tǒng)系統(tǒng)可靠度理論算法中存在的約界困難、精度有限以及工作量大等固有缺陷,從系統(tǒng)層面出發(fā),引入了結(jié)構(gòu)系統(tǒng)極限狀態(tài)曲面的概念。在此基礎(chǔ)上,利用支持向量分類算法對(duì)該極限狀態(tài)曲面進(jìn)行了直接重構(gòu)。以此為依據(jù)并結(jié)合LHS抽樣遷移策略,建立了計(jì)算結(jié)構(gòu)系統(tǒng)可靠度的SVC抽樣遷移計(jì)算方法。兩典型標(biāo)準(zhǔn)算例驗(yàn)證結(jié)果表明,所提出算法具有較高的計(jì)算精度、抽樣效率以及求解穩(wěn)定性,可有效避免現(xiàn)有算法中的固有弊端,更適用于實(shí)際結(jié)構(gòu)可靠度問題的分析求解。3.大跨度鋼斜拉橋荷載及抗力統(tǒng)計(jì)概率模型研究。在廣泛調(diào)研和數(shù)據(jù)收集的基礎(chǔ)上,通過梁段稱重結(jié)果以及其他既有統(tǒng)計(jì)分析,對(duì)大跨度鋼斜拉橋永久作用的統(tǒng)計(jì)概率模型進(jìn)行了深入研究。然后針對(duì)橋梁施工及運(yùn)營(yíng)特點(diǎn),并結(jié)合既有研究成果,獲取了結(jié)構(gòu)施工及運(yùn)營(yíng)階段中各類可變作用的統(tǒng)計(jì)概率模型。最后通過廣泛的文獻(xiàn)調(diào)研總結(jié),較為完整地確定了適用于大跨度鋼斜拉橋系統(tǒng)可靠度分析的塔、梁抗力統(tǒng)計(jì)概率模型,為后續(xù)系統(tǒng)可靠度的計(jì)算研究奠定了基礎(chǔ)。4.平行鋼絲斜拉索極限抗力概率模型研究。針對(duì)平行鋼絲斜拉索構(gòu)造組成以及受力特點(diǎn),利用概率統(tǒng)計(jì)理論并結(jié)合鋼絲試驗(yàn)結(jié)果,對(duì)索中鋼絲的抗力概率模型進(jìn)行了深入研究。在此基礎(chǔ)上,根據(jù)鋼絲串并聯(lián)組成關(guān)系(Daniels概率強(qiáng)度模型)并結(jié)合Monte Carlo數(shù)值模擬方法,提出了計(jì)算平行鋼絲斜拉索抗力的數(shù)值抽樣算法。聯(lián)合應(yīng)用這一算法以及構(gòu)件可靠度分析理論,對(duì)大跨度鋼斜拉橋斜拉索的構(gòu)件可靠性開展了研究。5.大跨度鋼斜拉橋施工及運(yùn)營(yíng)期系統(tǒng)可靠度研究�；谒⒌暮奢d及抗力統(tǒng)計(jì)概率模型,以典型特大跨度鋼斜拉橋——蘇通長(zhǎng)江大橋?yàn)檠芯繉?duì)象,采用所提出的SVC抽樣遷移計(jì)算方法,分別對(duì)結(jié)構(gòu)施工及運(yùn)營(yíng)過程中8種關(guān)鍵工況的系統(tǒng)可靠度問題進(jìn)行了深入探討。系統(tǒng)研究了各工況結(jié)構(gòu)首要失效模式災(zāi)變機(jī)理以及系統(tǒng)可靠度指標(biāo)的變化情況,從而較為全面地獲得了蘇通長(zhǎng)江大橋及類似橋梁施工及運(yùn)營(yíng)過程中各關(guān)鍵工況的系統(tǒng)可靠性演化規(guī)律。
[Abstract]:With the rapid development of the cable-stayed bridge to the large span in recent years, its structural forms are becoming more and more large-scale, complicated and flexible. The surpassing of large span steel cable-stayed bridges on scale scale poses a greater challenge to the overall safety performance of the structure, and the problem of system reliability in the construction and operation period is also more prominent. In this paper, in view of the inherent difficulties in the theoretical and practical analysis of the existing system reliability, from the concept of the system limit state surface, the support vector classification algorithm (SVC) and the LHS sampling migration strategy are introduced into the research of the system reliability theory, and the defects of the existing reliability index algorithms are improved. With the correction, the theoretical method of system reliability is further perfected. On this basis, based on the obtained statistical probability model, the system reliability evolution law and characteristics of the large span steel cable-stayed bridge during the construction and operation period are deeply studied and discussed. The completed research work mainly includes the following five aspects: 1. structure can be done In view of the inherent defects in the convergence and calculation efficiency of the traditional structure reliability index algorithm, based on the theoretical principle and engineering application, the first two order moment reliability index of the calculation structure is proposed based on the direction correction principle, based on the theory and engineering application. Through theoretical deduction and geometric analysis, the Monte Carlo method of line sampling is modified to improve its applicability. Finally, the two order expansion of the improved functional function is studied by numerical sampling and regression analysis, and the prediction calculation based on nonlinear regression analysis is established. The two times two order moment reliability index calculation method. Based on the representative numerical example, the validity and superiority of the proposed method.2. based on the system reliability theory algorithm based on SVC sampling migration is studied. From the system level, the concept of the limit state surface of the structural system is introduced. On this basis, the support vector classification algorithm is used to reconstruct the limit state surface directly. Based on the LHS sampling migration strategy, a SVC sampling transfer calculation method for calculating the reliability of the structural system is established. Two typical standard calculation examples are given. The results show that the proposed algorithm has high calculation precision, sampling efficiency and solution stability. It can effectively avoid the inherent disadvantages of existing algorithms. It is more suitable for the analysis of actual structural reliability problems to solve the statistical probability model of load and resistance of.3. long-span steel cable-stayed bridges. The statistical probability model of permanent action of long span steel cable-stayed bridge is studied through the weighing result of beam section and other statistical analysis, and then the statistical probability model of various variable functions in the construction and operation stage is obtained by combining the characteristics of the bridge construction and operation and combining with the existing research results. Finally, the statistical probability model is obtained. A comprehensive study on the reliability analysis of the long-span steel cable-stayed bridge system is made by extensive literature investigation and summary, and the statistical probability model of the beam resistance is established, which lays a foundation for the study of the probability model for the ultimate resistance of the.4. parallel wire cable-stayed cable for the calculation and study of the reliability of the subsequent system. By using the probability statistics theory and the result of steel wire test, the resistance probability model of wire in cable is deeply studied. On this basis, a numerical sampling algorithm for calculating the resistance of parallel wire cable-stayed cables is proposed based on the Daniels probability intensity model and the Monte Carlo numerical simulation method. With the application of this algorithm and the theory of component reliability analysis, the reliability of the construction and operation period of.5. long-span steel cable-stayed bridge is studied. Based on the statistical probability model of load and resistance, the typical large span steel cable-stayed bridge, Sutong Yangtze River bridge is used as a typical special long span steel cable-stayed bridge. By using the proposed SVC sampling migration calculation method, the system reliability of the 8 key working conditions in the construction and operation process is discussed. The catastrophe mechanism of the primary failure modes and the changes of the reliability index of the system are systematically studied. The evolution of system reliability under various critical conditions during construction and operation of similar bridges in Yangtze River bridge.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：U445;U448.27
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本文編號(hào)：2040887