大跨径系杆拱桥吊杆张拉过程中拱肋的稳定性研究

Stability Study of Arch Rib of Long-Span Arch Bridge during Suspender Tensioning Process

钢管混凝土系杆拱桥通过吊杆将桥面系和拱肋联成整体,共同承受荷载.在支架法施工中,吊杆张拉过程中拱肋的稳定性会发生变化,对桥梁施工安全产生重要影响.因此,以一座钢管混凝土系杆拱桥为研究对象,利用ANSYS软件建立有限元模型,模拟并分析了吊杆张拉过程中拱肋稳定性的变化规律.结果表明,吊杆张拉过程中拱肋的稳定性逐渐降低,且张拉过程中均为侧倾对称失稳,最大位移点位于最外侧横撑与拱肋的交接处.故应在施工中加强拱肋横撑和横向外部施工临时支撑,以提高施工中拱肋的稳定性,满足施工安全要求.

After Steel Pipe Concrete Tied-arch Bridge joins floor system and arch rib into a whole, they bear the load to- gether. In the support construction, the rib stability will change during the tensioning process of the suspender, which leaves an important impact on the bridge construction. Therefore, a Steel Pipe Concrete Tied-arch Bridge will be calculated and analyzed as an example. Through the simulation of the tensioning process by ANSYS, variation rules of rib stability will be studied. The results show that in the process of suspender tensioning the stability of the arch ribs reduce gradually, and ribs are all symmetrical roll instability, and the maximal displacement points are located in the junction of the outermost crossbars and arch ribs. In order to improve the stability of the arch ribs and satisfy the requirements of construction safety, rib cross- bars and lateral external temporary supports should be strengthened in the construction.