【摘要】：箱形截面梁由于具有很好的結(jié)構(gòu)特點(diǎn)和受力性能,故在連續(xù)梁橋和連續(xù)剛構(gòu)橋中廣泛應(yīng)用。箱梁具有橫向懸臂板寬、腹板間距大以及箱壁薄等特點(diǎn),其翼板在承受荷載時(shí)存在不均勻的剪切變形,截面正應(yīng)力沿截面不再是直線分布,而是呈曲線分布,即剪力滯現(xiàn)象。忽略剪力滯效應(yīng)的影響將會導(dǎo)致結(jié)構(gòu)設(shè)計(jì)的不安全,嚴(yán)重時(shí)有可能造成橋梁結(jié)構(gòu)的破壞�？v向預(yù)應(yīng)力對梁體的作用本質(zhì)上與軸向力存在著密切的關(guān)系,而目前針對軸向力作用下的剪力滯效應(yīng)研究較少。本文基于剪力滯效應(yīng)的原理,指出軸向力及縱向預(yù)應(yīng)力作用下箱梁將產(chǎn)生剪力滯效應(yīng),運(yùn)用有限元軟件ANSYS對薄壁箱梁剪力滯效應(yīng)影響進(jìn)行數(shù)值分析,得到并總結(jié)剪力滯效應(yīng)沿梁縱向分布的規(guī)律。目的在于研究軸向力及預(yù)應(yīng)力作用下箱梁剪力滯效應(yīng)及箱梁剪力滯的變化規(guī)律,可以為工程實(shí)踐提供一定參考。主要的研究工作包括:數(shù)值分析探討軸向力所引起的縱向應(yīng)力的分布規(guī)律,選取簡支、懸臂兩種基本邊界條件下的薄壁箱梁作為研究對象,區(qū)分對稱荷載和偏心壓力荷載兩種不同荷載類型,以及箱梁頂板有懸臂和無懸臂兩種情況,進(jìn)行計(jì)算比較分析,從而反映不同荷載作用下各控制截面頂板、底板正應(yīng)力值橫向分布的變化差異,以及剪力滯效應(yīng)沿縱向的變化情況,以便在結(jié)構(gòu)設(shè)計(jì)和理論研究時(shí)作為參考。此外,本文以某16+2?20+16m的實(shí)際連續(xù)箱梁橋?yàn)楣こ瘫尘?研究施工階段施加縱向預(yù)應(yīng)力導(dǎo)致的梁體截面上的剪力滯效應(yīng)。采用理論計(jì)算和有限元程序?qū)︻A(yù)應(yīng)力混凝土連續(xù)梁橋的各控制截面的截面正應(yīng)力進(jìn)行了計(jì)算分析,探討了后張法構(gòu)件曲線布筋情況下預(yù)加力對連續(xù)箱梁橋各控制截面剪力滯效應(yīng)的影響,以及剪力滯效應(yīng)沿橋梁縱向的變化情況;依據(jù)規(guī)范計(jì)算施工階段的預(yù)應(yīng)力損失并在有限元程序中予以實(shí)現(xiàn),對比分析了考慮預(yù)應(yīng)力損失和未考慮預(yù)應(yīng)力損失的情況下,縱向預(yù)應(yīng)力產(chǎn)生的剪力滯效應(yīng),并計(jì)算考慮自重后的剪力滯效應(yīng)變化,可為實(shí)際工程設(shè)計(jì)及施工提供參考。
[Abstract]:Box section beams are widely used in continuous beam bridges and continuous rigid frame bridges because of their good structural characteristics and mechanical properties. Box girder has the characteristics of transverse cantilever plate width, large web spacing and thin box wall. There is uneven shear deformation in the wing plate under load, and the normal stress distribution along the section is no longer linear, but curve distribution, that is, shear lag phenomenon. Ignoring the effect of shear lag will lead to the unsafe design of the structure, which may lead to the destruction of the bridge structure. The action of longitudinal prestress on beam body is essentially closely related to axial force, but there is little research on shear lag effect under axial force at present. Based on the principle of shear lag effect, this paper points out that the box girder will produce shear lag effect under axial force and longitudinal prestressing force. The influence of shear lag effect on thin-walled box girder is analyzed numerically by finite element software ANSYS. The law of longitudinal distribution of shear lag effect along the beam is obtained and summarized. The purpose of this paper is to study the shear lag effect of box girder and the variation law of box girder shear lag under the action of axial force and prestress, which can provide a certain reference for engineering practice. The main research work is as follows: the distribution of longitudinal stress caused by axial force is analyzed numerically, and thin wall box girder with simple support and cantilever is selected as the object of study. Two different load types, symmetrical load and eccentric pressure load, and cantilever and no cantilever on the roof of box girder are distinguished, and calculated and analyzed, so as to reflect the control section roof under different loads. The variation of the transverse distribution of the normal stress and the variation of the shear lag along the longitudinal direction are used as references for the structural design and theoretical study. In addition, the shear lag effect on beam section caused by longitudinal prestressing in construction stage is studied in this paper, which is based on a practical continuous box girder bridge with 162m and 2016m. The normal stress of each control section of prestressed concrete continuous beam bridge is calculated and analyzed by theoretical calculation and finite element program. The influence of prestress on the shear lag effect of each control section of continuous box girder bridge and the variation of shear lag effect along the longitudinal direction of continuous box girder bridge are discussed. The prestress loss in construction stage is calculated according to the code and realized in the finite element program. The shear lag effect caused by longitudinal prestress is compared and analyzed when the prestress loss is taken into account and the prestress loss is not taken into account. The change of shear lag effect considering deadweight can be used as a reference for practical engineering design and construction.
【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】：2015
【分類號】：U441

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 祝明橋;魏啟智;曾垂軍;蔣偉忠;;混凝土薄壁連續(xù)箱梁剪力滯效應(yīng)分析與對比[J];湘潭大學(xué)自然科學(xué)學(xué)報(bào);2009年03期

，

本文編號：2192948