横撑对钢管混凝土桁肋提篮拱桥横向弹性稳定的影响

Effects of Crossbars on the Lateral Elastic Stability of Lift-Basket CFST Truss Rib Arch Bridge

目的研究横撑的各种情况对钢管混凝土桁肋提篮拱桥横向弹性稳定的影响,得出横撑的合理布置间距及构造措施.方法利用有限元软件ANSYS建立模型并进行横撑对其拱肋的横向稳定分析,得到横撑布置间距、横撑型式和横撑刚度等参数对拱肋的横向弹性稳定的作用,判断出横撑影响拱桥横向稳定的主要因素.结果随着横撑布置间距的减小,桥梁的横向稳定性得到提高,然后趋于平缓;"X"型和"米"字型横撑有较高的横向稳定性;横撑刚度的变化对其横向稳定影响不大.结论选择合适实际情况的横撑间距可增加横向稳定性且简化施工程序;根据实际情况选用"X"型和"米"字型横撑都能得到较高的横向稳定性;适当选择横撑刚度既保证不发生局部失稳即可,又可以减轻自重.

In order to get rational arrangements of crossbars and structural layouts, the lateral elastic stability of the lift-basket CFST truss rib arch bridge with different crossbar layouts was analyzed. Using the FE software ANSYS, a finite element model was built and effects of crossbar spacing, style and stiffness on lateral stability of arch ribs and main factors were obtained. Results show that with decrease of crossbar spacing, the bridge lateral stability can be increased firstly, and then has a tendency to be not changed. But applying the ＂X＂ and the＂米＂ type of crossbar layouts can get higher lateral stability. It is also observed that the crossbar stiffness has little effect on the lateral stability of arch ribs. Conclusion is that rationally selecting crossbar spacing can increase the lateral stability and simplify the work procedures. According to the actual situations, choosing＂ X＂ type or ＂米＂ type can both get the high lateral stability. In consideration of little effects of crossbar stiff-ness on the lateral stability, for reducing the weight, it suffices to select the crossbar stiffness to only ensure the local buckling does not occur.