【摘要】：混凝土箱梁橋的開裂現(xiàn)象普遍存在，，被認(rèn)為是混凝土箱梁的“癌癥”。其裂縫的開展，不僅嚴(yán)重影響結(jié)構(gòu)的耐久性，而且加劇了箱梁橋的撓度。因此，本文對混凝土薄壁箱梁的開裂與撓度之間的關(guān)系進(jìn)行理論研究，探尋相關(guān)規(guī)律，具有重要的理論意義和工程應(yīng)用價值。本文主要完成了以下幾個方面的工作： （1）對國內(nèi)外箱梁撓度計(jì)算的研究歷程和發(fā)展現(xiàn)狀進(jìn)行綜述，結(jié)合混凝土薄壁箱梁裂縫現(xiàn)象的相關(guān)研究，提出了本文研究的主要內(nèi)容。 （2）考慮了鋼筋混凝土箱梁的材料非線性，采用大型分析軟件ANSYS，基于Drucker-Prage五參數(shù)破壞準(zhǔn)則和隨機(jī)強(qiáng)化模型，建立了簡支鋼筋混凝土箱梁的有限元模型。 （3）對箱梁模型分級加載至裂縫寬度達(dá)到預(yù)測值。研究箱梁模型正截面裂縫和斜截面裂縫的開展情況、分布規(guī)律，以及各級荷載作用下的鋼筋應(yīng)力變化情況和撓度變化情況。將上述結(jié)果與相應(yīng)的箱梁試驗(yàn)測試值對比發(fā)現(xiàn)兩者數(shù)值吻合的較好。驗(yàn)證了通過采用本文所建立的有限元模型研究混凝土薄壁箱梁開裂對撓度的影響是可行的。 （4）在既有文獻(xiàn)的基礎(chǔ)上，對影響撓度的各因素，如開裂后的彎曲變形、剪力滯效應(yīng)、剪切變形等，對撓度的影響進(jìn)行定量的分析。在分析剪切變形導(dǎo)致的撓度增大過程中，依據(jù)變角桁架模型，考慮了斜截面裂縫的開展對剪切變形的影響。
[Abstract]:The cracking phenomenon of concrete box girder bridge is common and is considered to be the "cancer" of concrete box girder. The development of cracks not only seriously affects the durability of the structure, but also aggravates the deflection of the box girder bridge. Therefore, this paper makes a theoretical study on the relationship between cracking and deflection of concrete thin-wall box girder, and explores the relevant laws, which is of great theoretical significance and engineering application value. This paper mainly completes the following aspects: (1) the research course and development status of box girder deflection calculation at home and abroad are summarized, combined with the related research of concrete thin-wall box girder crack phenomenon, The main contents of this paper are put forward. (2) considering the material nonlinear of reinforced concrete box girder, the finite element model of simply supported reinforced concrete box girder is established by using the large-scale analysis software ANSYS, based on Drucker-Prage five-parameter failure criterion and random strengthening model. (3) the predicted value is obtained from the graded loading of the box girder model to the crack width. The development and distribution of normal section cracks and oblique section cracks in box girder model, as well as the stress variation and deflection variation of steel bars under various loads are studied. By comparing the above results with the corresponding box girder test values, it is found that the two values are in good agreement with each other. It is verified that it is feasible to study the influence of cracking of concrete thin-wall box girder on deflection by using the finite element model established in this paper. (4) on the basis of the existing literature, the influence of deflection, such as bending deformation after cracking, shear lag effect, shear deformation and so on, is analyzed quantitatively. In the process of analyzing the increase of deflection caused by shear deformation, according to the variable angle truss model, the influence of oblique section crack development on shear deformation is considered.
【學(xué)位授予單位】：蘭州交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U441;U448.213

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本文編號：2480986