考虑几何非线性的钢管混凝土拱桥徐变效应研究

Study on Creep Effect of Concrete Filled Steel Tubular Arch Bridge Considering Geometric Nonlinearity

基于微分法推导了考虑几何非线性大转动小应变的平面梁单元非线性平衡方程,利用Fortran自编程软件对某大桥平面模型分别进行了有无非线性影响的徐变效应分析,以初应变法模拟混凝土徐变效应,用对数形式对龄期进行划分,分析计算了龄期1000 d徐变效应的变化数据。结果表明考虑几何非线性相较于线性下的徐变分析数值差异达到5%左右,在大荷载与大跨径的情况下,结构非线性更为明显,其双重非线性考虑更有必要。

Based on the differential method,the nonlinear equilibrium equation of plane beam element considering geometric nonlinearity,large rotation and small strain is derived.The creep effect of a bridge plane model is analyzed by using Fortran self programming software with or without nonlinear influence.The concrete creep effect is simulated by the initial strain method.The age is divided by logarithm form,and the creep effect change of 1000 days age is analyzed and calculated.The results show that the difference between the creep anal‐ysis with geometric nonlinearity and linear creep analysis is about 5%.In the case of large load and long span,the structural nonlinearity is more obvious,and the dual nonlinearity is more necessary.