铰接钢管混凝土圆弧拱平面内徐变稳定

IN-PLANE CREEP BUCKLING FOR PIN-ENDED CONCRETE-FILLED STEEL TUBULAR CIRCULAR ARCHES

钢管混凝土拱肋核心混凝土徐变不仅可以导致钢管与混凝土之间的内力重分布,还将增加拱肋的屈曲前变形,降低拱肋的稳定承载力。经典稳定理论假设拱的屈曲前变形呈线性且该变形较小,因此忽略了屈曲前变形对拱肋弹性稳定承载力的影响。该假设仅适用于矢跨比较大的深拱,由于浅拱的屈曲前变形具有明显的非线性特征,该理论不再适用。尤其考虑徐变对拱的稳定承载力影响时,必须计入屈曲前变形的影响。该文根据钢管混凝土组合构件的徐变特性,基于考虑龄期调整的等效弹性模量方法,采用虚功原理建立了铰接钢管混凝土圆弧拱的非线性静力平衡方程和稳定平衡方程,并通过联立求解两种方程得到了徐变作用对拱肋稳定承载力的影响;此外,该文还探讨了徐变系数对徐变稳定性的影响,以及稳定承载力随拱桥运营时间的变化规律。

The core concrete creep in concrete-filled steel tubular（CFST） arches changes the internal force distribution between steel tube and core concrete;moreover,it increases the pre-buckling deformation which will reduce the in-plane buckling resistance significantly.The classical buckling theory which assumes that the arches have linear pre-buckling behaviors and the effects of pre-buckling deformation can be ignored is not suitable for predicting the in-plane buckling of CFST arches considering creep,especially for shallow CFST arches in which the pre-buckling deformation has a notable effect on the stability behavior.Based on the creep characteristics of CFST arches and the age-adjusted effective modulus method,the nonlinear in-plane equilibrium and buckling equations for CFST arches are established by using a virtual work formulation.By solving these equations,the effect of core concrete creep on the stability of CFST arches has been adopted.In addition,the influence of creep coefficient has been investigated,and the relationship between creep buckling behaviors and service time has also been discussed in this paper.