本文關(guān)鍵詞： 鋼管混凝土拱橋 可靠度分析 正常使用極限狀態(tài) BP神經(jīng)網(wǎng)絡(luò) JC法　出處：《長(zhǎng)安大學(xué)》2015年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：本文基于橋梁結(jié)構(gòu)可靠度基本理論,針對(duì)現(xiàn)有可靠度分析方法在工程應(yīng)用中存在的問(wèn)題,將BP神經(jīng)網(wǎng)絡(luò)與改進(jìn)JC算法相結(jié)合,對(duì)鋼管混凝土拱橋正常使用極限狀態(tài)可靠度進(jìn)行計(jì)算,為鋼管混凝土拱橋可靠度評(píng)估提供理論參考。主要研究?jī)?nèi)容如下:(1)根據(jù)極限狀態(tài)基本定義,明確鋼管混凝土拱橋正常使用極限狀態(tài)下作用及抗力概率模型,討論傳統(tǒng)可靠度計(jì)算方法在鋼管混凝土拱橋結(jié)構(gòu)分析中存在的缺陷,并結(jié)合梯度計(jì)算法,得出鋼管混凝土拱橋極限狀態(tài)方程參數(shù)靈敏性分析方法。(2)基于橋梁結(jié)構(gòu)可靠度基本理論及鋼管混凝土拱橋結(jié)構(gòu)特點(diǎn),結(jié)合神經(jīng)網(wǎng)絡(luò)理論,采用均勻設(shè)計(jì)法,將結(jié)構(gòu)功能函數(shù)顯式化。通過(guò)改進(jìn)JC算法迭代方式,求解由BP神經(jīng)網(wǎng)絡(luò)擬合出的非線性功能函數(shù),提高結(jié)構(gòu)可靠度分析精度,實(shí)現(xiàn)從結(jié)構(gòu)體系層面對(duì)鋼管混凝土拱橋正常使用極限狀態(tài)撓度、應(yīng)力可靠度的評(píng)估,提出完整的可靠度分析、計(jì)算方法。并以MATLAB計(jì)算程序?yàn)槠脚_(tái),采用系統(tǒng)化、模塊化設(shè)計(jì)思路編制可靠度分析程序,并結(jié)合簡(jiǎn)單算例對(duì)程序可行性及準(zhǔn)確性進(jìn)行驗(yàn)證。(3)建立實(shí)橋有限元模型,利用BP神經(jīng)網(wǎng)絡(luò)與改進(jìn)JC算法,從撓度及應(yīng)力兩方面對(duì)實(shí)橋工程可靠性進(jìn)行評(píng)估,研究鋼管混凝土拱橋正常使用極限狀態(tài)的主要失效模式。并基于主要受力構(gòu)件應(yīng)力可靠度指標(biāo),建立鋼管混凝土拱橋的結(jié)構(gòu)等效體系及簡(jiǎn)化等效體系,計(jì)算了等效串聯(lián)體系模式下結(jié)構(gòu)應(yīng)力可靠度指標(biāo)。分析可靠度指標(biāo)對(duì)正常使用極限狀態(tài)方程參數(shù)的靈敏性,并結(jié)合靈敏度計(jì)算結(jié)果,減少隨機(jī)變量個(gè)數(shù),簡(jiǎn)化可靠度計(jì)算過(guò)程。
[Abstract]:In this paper, based on the basic theory of bridge structure reliability, the BP neural network and the improved JC algorithm are combined to solve the problems existing in the existing reliability analysis methods. The limit state reliability of CFST arch bridge is calculated, which provides a theoretical reference for the reliability evaluation of CFST arch bridge. The main research contents are as follows: 1) according to the basic definition of limit state, The function and resistance probability model of CFST arch bridge under the limit state of normal use is defined. The defects of traditional reliability calculation method in structural analysis of CFST arch bridge are discussed, and the gradient calculation method is combined. Based on the basic theory of reliability of bridge structure and the structural characteristics of concrete-filled steel tube arch bridge, the uniform design method is adopted in combination with the neural network theory. By improving the iterative method of JC algorithm, the nonlinear functional function fitted by BP neural network is solved, and the precision of structural reliability analysis is improved. In this paper, the deflection and stress reliability of concrete-filled steel tubular arch bridge under normal use are evaluated from the structural system level, and a complete reliability analysis and calculation method is put forward. Based on the MATLAB calculation program, the system is adopted. The reliability analysis program is compiled by modularization design idea, and the feasibility and accuracy of the program are verified by a simple example. The finite element model of the real bridge is established, and the BP neural network and the improved JC algorithm are used. In this paper, the reliability of real bridge is evaluated from deflection and stress, and the main failure modes of concrete filled steel tube arch bridge under normal service limit state are studied, and based on the stress reliability index of main stress components, the failure mode of concrete filled steel tube arch bridge is studied. The structural equivalent system and simplified equivalent system of concrete-filled steel tubular arch bridge are established, and the structural stress reliability index under the equivalent series system mode is calculated. The sensitivity of the reliability index to the parameters of the limit state equation of normal use is analyzed. Combined with the result of sensitivity calculation, the number of random variables is reduced and the process of reliability calculation is simplified.
【學(xué)位授予單位】：長(zhǎng)安大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：U448.22;U441

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本文編號(hào)：1503895