水平底板索连续刚构桥施工阶段混凝土收缩徐变效应研究

Research on the Effects of Concrete Shrinkage and Creep during the Construction Stage of Continuous Rigid-Frame Bridge with Horizontal Bottom Slab Cables

摘要: 以贵州山区某高墩大跨水平底板索连续刚构桥为工程背景，采用有限元方法研究了混凝土收缩徐变对水平底板索连续刚构桥施工阶段力学性能的影响，并分析了环境相对湿度和混凝土加载龄期对桥梁施工阶段力学性能的影响。研究发现，在不同施工阶段，考虑混凝土收缩徐变时水平底板索连续刚构桥的挠度均大于不考虑混凝土收缩徐变时的挠度，而考虑混凝土收缩徐变时桥梁的压应力均略小于不考虑混凝土收缩徐变时的压应力。并且，随着环境相对湿度的增大，桥梁的挠度会减小，而压应力几乎不变。此外，随着混凝土加载龄期的增大，桥梁的挠度会先增大后减小，而压应力几乎不变。本文研究成果可为水平底板索连续刚构桥的设计和施工提供有益的指导。

Abstract: Taking a high-pier and large-span continuous rigid-frame bridge with horizontal bottom slab cables (CRFB-HBSC) in the mountainous area of Guizhou as the engineering background, the influence of concrete shrinkage and creep on the mechanical properties of the bridge during construction was studied using the finite element method, and the effects of environmental relative humidity and concrete loading age on the mechanical properties of the bridge during construction were analyzed. It was found that, at different construction stages, the deflection of the CRFB-HBSC considering concrete shrinkage and creep was greater than that without considering it, while the compressive stress of the bridge considering concrete shrinkage and creep was slightly smaller than that without considering it. Moreover, as the environmental relative humidity increased, the deflection of the bridge decreased, while the compressive stress remained almost unchanged. In addition, as the concrete loading age increased, the deflection of the bridge first increased and then decreased, while the compressive stress remained almost unchanged. The research results of this paper can provide beneficial guidance for the design and construction of CRFB-HBSC.