高速铁路钢桁加劲混凝土连续刚构桥梁长期行为预测研究

以一座在建高速铁路钢桁加劲连续刚构桥为对象,研究混凝土收缩徐变对其变形及内力的影响规律,探讨钢桁对连续刚构桥梁变形的影响机理,并研究环境湿度、加载龄期等因素对桥梁变形的影响程度。结果表明:收缩徐变效应引起桥梁的变形及内力均随时间增长而增加,钢桁使桥梁整体刚度大幅提高;安装钢桁可有效减小各阶段桥梁弯矩和变形,但钢桁对桥墩的水平变形抑制作用较小,建议采用合龙口顶推方式进行反向顶推以减小桥墩水平变形;环境湿度和加载龄期对钢桁加劲连续刚构桥梁的影响表现为挠度随加载龄期及相对湿度的增加而减小。

Prediction on the Long-term Behavior of Continuous Rigid Frame Bridge Stiffened by Steel Truss in High Speed Railway

Taking a continuous rigid frame bridge stiffened by steel truss in high speed railway as an example,theinfluence law of concrete shrinkage and creep on its deformation and internal force was studied,the influencemechanism of steel truss on the deformation of continuous rigid frame bridge was discussed,and the influence degree ofenvironmental humidity,loading age and other factors on bridge deformation was studied.The results show that thedeformation and internal force of the bridge increase with time due to shrinkage and creep effect,and the overallstiffness of the bridge is greatly improved by steel truss.The steel truss can effectively reduce the bending moment anddeformation of the bridge at each stage,but the steel truss has little inhibition effect on the horizontal deformation of thepier.In order to reduce the horizontal deformation of the pier,it is suggested to adopt the jacking method of closureopening for reverse pushing.The influence of environmental humidity and loading age on continuous rigid frame bridgestiffened by steel truss shows that the deflection decreases with the increase of loading age and relative humidity.