考虑几何非线性及施工的钢管混凝土拱桥徐变

Creep of Concrete-Filled Steel Tube Arch Bridge Considering Geometric Nonlinearity and Construction

为研究大跨度钢管混凝土拱桥的徐变行为,基于混凝土徐变的B3模型,采用结构徐变效应分析的龄期调整有效模量法,建立了结构徐变的有限元分析模型.在此基础上,基于协同转动法考虑大跨度结构的几何非线性;利用生死单元技术模拟拱桥的分阶段施工过程;最后结合某大跨度中承式钢管混凝土拱桥,分析了考虑几何非线性和施工过程的徐变效应.数值分析表明:考虑这两个因素后拱肋挠度、钢管应力的变化在10%以内,而拱肋混凝土应力的变化可达50%;在分析大跨度钢管混凝土拱桥的徐变效应时,必须考虑几何非线性及施工过程与徐变的耦合作用.

In order to investigate the creep behavior of long-span concrete filled steel tube （CFST） arch bridges, a finite element model for structural creep was developed using the age-adjusted effective modulus method based on the B3 model for concrete creep. In this framework, the corotational approach for geometric nonlinearity and the technique of element birth and death for simulating different construction stages were also introduced. A long-span half-through CFST arch bridge was analyzed as a numerical application to analyze the impact of geometric nonlinearity and construction process on creep. The calculated results demonstrate that considering the geometric nonlinearity and construction process makes the deflection and stress in steel tube change less than 10% , but leads to a change of 50% in the stress in concrete core. The coupling effect between creep and geometric nonlinearity/construction process is not negligible in the creep analysis of long-span CFST arch bridges.