收缩徐变对高速铁路钢筋混凝土拱桥时变应力影响的概率分析

Probabilistic Analysis on Influence of Creep and Shrinkage on Time-variant Stresses of High-speed Railway Reinforced Concrete Arch Bridge

采用劲性骨架技术施工的大跨度钢筋混凝土拱桥,由收缩徐变产生的长期效应十分复杂。由于混凝土收缩徐变具有随机特点,结构时变应力表现出明显的不确定性。对于大跨度混凝土桥梁等一些大型结构,确定性分析已经不能满足工程实践的要求,建议采用随机分析的方法。本文建立了基于GL2000模型的混凝土长期应变随机发展方程。采用基于响应面的蒙特卡洛法对高速铁路大跨度钢筋混凝土拱桥的时变应力进行概率分析。利用敏感性分析技术,研究了随机变量对结构应力的随机影响。

For long-span reinforced concrete arch bridges constructed with the stiffening frame technique,the long-term effect caused by creep and shrinkage may be extremely sophisticated.Owing to the stochastic properties of creep and shrinkage,the long-term variation of stresses exhibits significant uncertainty.For such large-scale structures as long-span concrete bridges,deterministic analysis can not meet the requirements of engineering practices,and probabilistic analysis is recommended.In this paper,the stochastic function of longterm stresses of concrete was presented on the basis of the GL2000 model.The probabilistic analysis on timevariant stresses of high-speed railway reinforced concrete arch bridges was carried out by Monte Carlo sampling combined with the response surface method.The uncertain influences of random variables on structural stresses were investigated by sensitivity analysis.