蝶形拱桥主梁的非线性行为及影响因素分析

Analysis of Nonlinearity Behavior of Main Beams of Butterfly-Shaped Arch Bridge and Its Influencing Factors

由于蝶形拱桥造型独特其主梁部分的非线性行为规律相对其他拱桥较为难以掌握,传统的未充分考虑非线性影响的设计方法已不再适用。在自编程序的基础上,全面分析了各种非线性因素下蝶形拱桥主梁部分的非线性行为并研究了外倾角、矢跨比、含钢率等设计参数的影响及规律。结果表明:拱肋单元的梁柱效应对主梁弯矩的影响是不利的,而主梁单元的梁柱效应能够有效地抵消这种不利影响;主梁弯矩的非线性行为规律相对挠度更加复杂;未加载侧边梁的影响系数受偏载距离的影响较大;各梁跨中挠度和弯矩的影响系数均随着主拱肋外倾角的增大而增大;主拱肋含钢率和索拱平面间夹角对主梁非线性行为的影响可以忽略。

Due to the unique pattern of butterfly-shaped arch bridge, the nonlinear behavior rules of main girders are difficult to master compared with ordinary arch bridges, the traditional design method which is not fully considered in nonlinear influence is not applicable. On the basis of self-compiled program, the nonlinear behaviors of main girders are analyzed considering various nonlinear factors, and the influence of many design parameters and its rules are studied such as angle of depression, rise/span ratio, steel ratio and so on. The results show that （1） the beam-column effect of arch rib elements has unfavorable effects on main beam moment, but the beam-column effect of main beam elements can effectively counteract the adverse effect; （2） the nonlinear behavior rules of main beam moment are more complicated than the rules of deformation; （3） the distance of eccentric load has a bigger influence on influence coefficients of boundary beams at unloading side; （4） the influence coefficients of midspan deformation and moment will increase as the angle of depression gets bigger; （5） the influence of steel ratio and the angle between cable plane and arch plane on nonlinear characteristics of main beams can be neglected.