本文選題：增大截面加固法 + 疲勞�。� 參考：《重慶交通大學(xué)》2015年碩士論文

【摘要】：現(xiàn)如今,隨著土木工程不斷建設(shè)發(fā)展,新的設(shè)計(jì)理念日tg完善,我國(guó)橋梁事業(yè),處于一個(gè)趨向穩(wěn)定的態(tài)勢(shì)。越來(lái)越多的科學(xué)工作者把目光轉(zhuǎn)向了已成橋的管理和養(yǎng)護(hù)方面。由于自然環(huán)境以及結(jié)構(gòu)自身不斷老化等因素,鋼筋混凝土在服役期限內(nèi),往往會(huì)出現(xiàn)各種各樣的損傷,達(dá)不到設(shè)計(jì)的壽命要求。本文依托實(shí)際工程,采用增大截面法進(jìn)行相關(guān)方面的試驗(yàn)設(shè)計(jì),系統(tǒng)的研究和分析加固后的鋼筋混凝土簡(jiǎn)支梁橋疲勞性能,設(shè)計(jì)了相關(guān)的試驗(yàn)研究方案。以鋼筋混凝土梁的損傷情況以及不同荷載作用下鋼筋的應(yīng)力水平為研究對(duì)象,采用增大截面的方法對(duì)鋼筋混凝土梁進(jìn)行了加固處理,并進(jìn)行了疲勞試驗(yàn),分析了循環(huán)荷載作用下加固梁相關(guān)的疲勞性能。主要研究了以下方面:①研究了使用增大截面法加固混凝土梁的力學(xué)性能和破壞形態(tài)。試驗(yàn)共設(shè)計(jì)了三組試件來(lái)進(jìn)行對(duì)比分析,第一組試件共2片梁,1片未經(jīng)過(guò)加固直接進(jìn)行靜載試驗(yàn)得到原梁極限承載能力以指導(dǎo)試驗(yàn)梁的受損加載(約為極限荷載u1P的0.85倍),另外1片加固后再進(jìn)行靜載試驗(yàn)以測(cè)得加固后梁的極限承載能力(u2P),指導(dǎo)試驗(yàn)梁的疲勞加載,同時(shí)得到了加固后混凝土梁的靜力性能。②研究了疲勞循環(huán)的荷載水平對(duì)加固混凝土梁疲勞性能的影響。第二組試件共3片梁,加固前不做受損處理進(jìn)行疲勞試驗(yàn)。疲勞荷載的下限值統(tǒng)一取0.1u2P,上限分別取0.5u2P、0.7u2P以及0.9u2P。研究在不同應(yīng)力條件下,加固梁的疲勞特性。③研究了預(yù)受損對(duì)增大截面法加固混凝土梁疲勞性能的影響。第三組試驗(yàn)共2片梁。2片梁在加固前均按0.85uP做了受損處理,然后進(jìn)行疲勞試驗(yàn),疲勞試驗(yàn)荷載水平與第二組后2片梁相同以進(jìn)行對(duì)比,研究前期預(yù)損傷行為對(duì)加固梁疲勞性能的影響。④結(jié)合試驗(yàn)數(shù)據(jù),通過(guò)線性擬合得到循環(huán)荷載作用下,增大截面加固混凝土梁的S?N曲線,為用增大截面加固的橋梁結(jié)構(gòu)的壽命預(yù)測(cè)提供了依據(jù)。⑤對(duì)疲勞損傷累積的機(jī)理進(jìn)行了探討。在試驗(yàn)數(shù)據(jù)和理論分析的基礎(chǔ)上運(yùn)用剩余剛度的方法對(duì)增大截面法加固的混凝土試驗(yàn)梁的損傷進(jìn)行了分析驗(yàn)證,得到了結(jié)構(gòu)疲勞破壞全過(guò)程三階段的發(fā)展規(guī)律。
[Abstract]:Nowadays, with the development of civil engineering and the improvement of new design concept, the bridge industry in our country is in a stable situationMore and more scientists are turning their eyes to the management and maintenance of the bridge.Due to the aging of the natural environment and the structure itself, various kinds of damage often occur in the service life of reinforced concrete, which can not meet the design life requirements.In this paper, based on the actual engineering, using the method of increasing section to carry out the related experimental design, the fatigue performance of reinforced concrete simply supported beam bridge is studied and analyzed systematically, and the related experimental research scheme is designed.Taking the damage of reinforced concrete beam and the stress level of steel bar under different loads as the object of study, the reinforced concrete beam was strengthened with the method of increasing section, and the fatigue test was carried out.The fatigue behavior of strengthened beams under cyclic load is analyzed.In this paper, the mechanical properties and failure modes of concrete beams strengthened with the method of increasing section are studied in the following aspects: 1.Three groups of specimens were designed for comparative analysis.In the first group of specimens, two beams and one piece of beam were tested under static load without reinforcement. The ultimate load-bearing capacity of the original beam was obtained to guide the damaged loading of the test beam (about 0.85 times of the limit load U1P), and the other one piece was strengthened and then tested under static load.The ultimate load-bearing capacity of the strengthened beam is measured and the fatigue loading of the test beam is guided.At the same time, the static behavior of reinforced concrete beam is obtained. 2. The influence of fatigue cyclic load level on the fatigue behavior of reinforced concrete beam is studied.The second group consists of 3 beams. Fatigue tests are carried out without damage treatment before reinforcement.The lower limit of fatigue load is 0.1u2P, the upper limit is 0.5u2P0. 7u2P and the upper limit is 0.9u2P.In this paper, the fatigue behavior of strengthened beams under different stress conditions is studied. 3. The effect of pre-damage on the fatigue behavior of reinforced concrete beams strengthened by increasing cross-section method is studied.In the third group, 2 beams were damaged according to 0.85uP before reinforcement, and then fatigue tests were carried out. The load level of fatigue test was the same as that of the second group.The influence of pre-damage behavior on fatigue behavior of strengthened beams was studied. 4. Based on the experimental data, the Sn-N curves of reinforced concrete beams were obtained by linear fitting under cyclic load.The mechanism of fatigue damage accumulation is discussed in this paper.On the basis of experimental data and theoretical analysis, the residual stiffness method is used to analyze and verify the damage of concrete test beams strengthened by increasing cross-section method, and the three-stage development rule of fatigue failure of structures is obtained.
【學(xué)位授予單位】：重慶交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：U445.72

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 張國(guó)棟,朱暾,丁紅瑞;碳纖維加固二次受力梁斜截面抗剪的試驗(yàn)研究[J];三峽大學(xué)學(xué)報(bào)(自然科學(xué)版);2001年01期

相關(guān)碩士學(xué)位論文 前1條

1 周希茂;增大截面法加固鋼筋混凝土框支架的非線性有限元分析[D];西安科技大學(xué);2009年

，

本文編號(hào)：1773509