本文選題：箱梁橋 + 極限承載力�。� 參考：《湖南科技大學(xué)》2015年碩士論文

【摘要】：鋼筋混凝土/預(yù)應(yīng)力混凝土箱梁橋在施工及正常使用過程中易開裂,特別是易出現(xiàn)腹板斜裂縫,因此應(yīng)對腹板主拉應(yīng)力分布規(guī)律進行研究。腹板斜裂縫的出現(xiàn)對橋梁的整體剛度、承載能力以及正常使用性能將產(chǎn)生很大影響,同時橋梁剛度下降又會進一步促進腹板裂縫的發(fā)展。國內(nèi)外關(guān)于箱梁腹板開裂對橋梁剛度、承載能力、使用性能的影響研究還不夠明確,大多只進行了定性描述而沒有形成一套量化的計算理論。對混凝土構(gòu)件開裂情況的模擬還不夠精確,特別是箱梁橋局部屈曲,非線性收斂等問題。本文以某預(yù)應(yīng)力混凝土箱梁橋為背景,在全面總結(jié)箱梁橋開裂原因及裂縫分布規(guī)律的前提下,利用空間實體有限元模型研究了箱梁橋的腹板受力特性。并以軟化桁架模型理論為基礎(chǔ),以小扭彎比的加載方式,建立了彎、剪、扭共同作用下的實體-桁架模型,在滿足與實體模型剛度等效的前提下,研究了箱梁橋在自重荷載、車道荷載正載與偏載荷載情況下的箱梁受力特性。并利用該實體-桁架模型進行了非線性計算,得出了箱梁的開裂荷載與極限承載力。本文取得的成果有如下幾個方面:1.在“軟化桁架理論”的基礎(chǔ)上提出了“實體-桁架”模型的數(shù)值分析與建模方法。2.建立了五種不同角度的實體-桁架模型,分析了箱梁撓度與腹板應(yīng)力受桁架斜桿傾角的影響情況,并得出了桁架斜桿傾角的優(yōu)選辦法。3.推導(dǎo)了“實體箱梁”與“實體-桁架箱梁”的剛度等效計算公式。4.分別建立了“實體模型”和“實體-桁架模型”,分別做了不同荷載工況下的數(shù)值計算與受力特性分析,通過非線性數(shù)值計算得出了箱梁橋腹板的開裂荷載和極限承載力。最后,本文針對研究中發(fā)現(xiàn)的問題展開了探討,并對實體-桁架模型理論的發(fā)展與實際應(yīng)用做了總結(jié)。
[Abstract]:The reinforced concrete / prestressed concrete box girder bridge is prone to crack during construction and normal use, especially the inclined cracks of web plate, so it is necessary to study the distribution law of main tensile stress of web plate. The emergence of inclined web cracks will have a great impact on the overall stiffness, bearing capacity and normal service performance of the bridge, and the reduction of bridge stiffness will further promote the development of web cracks. At home and abroad, the influence of box girder web cracking on bridge stiffness, bearing capacity and service performance is not clear enough, most of them are only qualitatively described without a set of quantitative calculation theory. The simulation of concrete member cracking is not accurate enough, especially the local buckling and nonlinear convergence of box girder bridge. Taking a prestressed concrete box girder bridge as the background, this paper, on the premise of summing up the cracking reason and crack distribution law of the box girder bridge, makes use of the finite element model of space entity to study the stress characteristics of the web plate of the box girder bridge. Based on the theory of softened truss model and the loading mode of small torsional bending ratio, the solid-truss model under the joint action of bending, shear and torsion is established. On the premise that the stiffness of the box girder bridge is equivalent to that of the solid model, the deadweight load of the box girder bridge is studied. The load characteristics of box girder under positive load and eccentric load in driveway. The cracking load and ultimate bearing capacity of the box girder are obtained by nonlinear calculation using the solid-truss model. The achievements of this paper are as follows: 1. On the basis of "softening truss theory", a numerical analysis and modeling method of "solid truss" model is proposed. Five kinds of solid truss models with different angles are established, and the influence of box girder deflection and web stress on the inclined angle of truss bar is analyzed, and the optimum selection method of inclined truss bar angle is obtained. The equivalent stiffness calculation formula of "solid box girder" and "solid truss box girder" is derived. The "solid model" and "solid-truss model" are established respectively, and the numerical calculation and the analysis of the stress characteristics under different load conditions are done respectively. The cracking load and ultimate bearing capacity of the web plate of the box girder bridge are obtained by nonlinear numerical calculation. Finally, this paper discusses the problems found in the research, and summarizes the development and practical application of the solid-truss model theory.
【學(xué)位授予單位】：湖南科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：U441;U448.213

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相關(guān)期刊論文 前1條

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本文編號：1954974