【摘要】：連續(xù)剛構(gòu)橋應(yīng)用廣泛但存在跨中下?lián)希后w裂縫等危害，這不僅影響到了行車舒適性，更對其發(fā)展有很大的阻礙。而合理的跨徑布置是減少這種危害的關(guān)鍵，因此有必要開展合理邊中跨比的研究。 本文以連續(xù)剛構(gòu)橋邊中跨比為研究對象，采用解析法和有限元法尋求合理邊中跨比值，為橋梁合理邊中跨比設(shè)計(jì)提供指導(dǎo)。首先利用結(jié)構(gòu)力學(xué)位移法進(jìn)行解析計(jì)算，得到三跨、四跨以及五跨三種跨度下的彎矩和梁端轉(zhuǎn)角公式，并分析在不同邊中跨比值下，橋梁不同控制截面下，彎矩和梁端轉(zhuǎn)角變化規(guī)律，理論分析結(jié)果表明邊中跨比對結(jié)構(gòu)彎矩的影響要遠(yuǎn)遠(yuǎn)大于其對梁端轉(zhuǎn)角影響。然后用MIDAS/CIVIL軟件，建立三跨橋梁有限元模型，從而進(jìn)一步分析基準(zhǔn)橋在自重荷載、車道荷載、整體升溫20℃、日照溫差荷載這四種載荷作用下的結(jié)構(gòu)內(nèi)力，，分析得出自重荷載、整體升溫20℃荷載作用對橋梁結(jié)構(gòu)內(nèi)力影響比較大，并且主梁主要承受彎矩和剪力，橋墩主要承受軸力。再然后以基準(zhǔn)橋?yàn)榛A(chǔ)，保持基準(zhǔn)橋總跨徑、主梁支點(diǎn)和跨中截面、橋墩幾何尺寸和截面不變，利用MIDAS/CIVIL軟件建立13種不同邊中跨比的三跨連續(xù)剛構(gòu)橋模型，并對這13種橋梁不同控制截面的內(nèi)力值進(jìn)行比較分析，得到當(dāng)邊中跨比為0.7時(shí)結(jié)構(gòu)受力比較合理，兩雙薄壁墩受力比較接近。最后對三跨連續(xù)剛構(gòu)橋進(jìn)行結(jié)構(gòu)優(yōu)化，以箱型主梁所需預(yù)應(yīng)力最小為目標(biāo)函數(shù)，建立優(yōu)化模型，并對計(jì)算所得預(yù)應(yīng)力進(jìn)行擬合，對擬合的二次函數(shù)進(jìn)行求導(dǎo)得到最合理邊中跨比值為0.702899，在實(shí)際應(yīng)用中選擇邊中跨比為0.7即可，這與有限元法計(jì)算的結(jié)果相吻合，故本文建議若三跨連續(xù)剛構(gòu)橋的參數(shù)與本文所取的參數(shù)比較接近時(shí)邊中跨比取0.7左右為宜。
[Abstract]:Continuous rigid frame bridges are widely used, but there are some hazards such as mid-span deflection and beam body cracks, which not only affect the driving comfort, but also hinder the development of continuous rigid frame bridges. The reasonable span arrangement is the key to reduce the harm, so it is necessary to study the reasonable side to middle span ratio. In this paper, the boundary span ratio of continuous rigid frame bridge is studied, and the analytical method and finite element method are used to find out the reasonable ratio of edge to span ratio, which provides guidance for the design of the reasonable span ratio of bridge edge. In this paper, the formulas of bending moment and beam end rotation angle under three span, four span and five span are obtained by means of structural mechanical displacement method. At the same time, the different control cross sections of bridge under different mid-span ratio are analyzed. The results of theoretical analysis show that the influence of the ratio of side to middle span on the moment of the structure is much greater than that on the angle of the end of the beam. Then the finite element model of three-span bridge is established by using MIDAS/CIVIL software, so as to further analyze the structural internal forces of the reference bridge under four kinds of loads: deadweight load, driveway load, whole heating temperature 20 鈩

本文編號：2290671