连续刚构桥边中跨比研究
发布时间：2018-10-24 07:06
【摘要】：连续刚构桥应用广泛但存在跨中下挠，梁体裂缝等危害，这不仅影响到了行车舒适性，更对其发展有很大的阻碍。而合理的跨径布置是减少这种危害的关键，因此有必要开展合理边中跨比的研究。 本文以连续刚构桥边中跨比为研究对象，采用解析法和有限元法寻求合理边中跨比值，为桥梁合理边中跨比设计提供指导。首先利用结构力学位移法进行解析计算，得到三跨、四跨以及五跨三种跨度下的弯矩和梁端转角公式，并分析在不同边中跨比值下，桥梁不同控制截面下，弯矩和梁端转角变化规律，理论分析结果表明边中跨比对结构弯矩的影响要远远大于其对梁端转角影响。然后用MIDAS/CIVIL软件，建立三跨桥梁有限元模型，从而进一步分析基准桥在自重荷载、车道荷载、整体升温20℃、日照温差荷载这四种载荷作用下的结构内力，，分析得出自重荷载、整体升温20℃荷载作用对桥梁结构内力影响比较大，并且主梁主要承受弯矩和剪力，桥墩主要承受轴力。再然后以基准桥为基础，保持基准桥总跨径、主梁支点和跨中截面、桥墩几何尺寸和截面不变，利用MIDAS/CIVIL软件建立13种不同边中跨比的三跨连续刚构桥模型，并对这13种桥梁不同控制截面的内力值进行比较分析，得到当边中跨比为0.7时结构受力比较合理，两双薄壁墩受力比较接近。最后对三跨连续刚构桥进行结构优化，以箱型主梁所需预应力最小为目标函数，建立优化模型，并对计算所得预应力进行拟合，对拟合的二次函数进行求导得到最合理边中跨比值为0.702899，在实际应用中选择边中跨比为0.7即可，这与有限元法计算的结果相吻合，故本文建议若三跨连续刚构桥的参数与本文所取的参数比较接近时边中跨比取0.7左右为宜。
[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
本文编号：2290671
[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
本文编号：2290671
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