徐变参数随机性对预应力混凝土桥梁长期变形的影响分析

Influence of Stochastic Creep Parameters on Long-term Deformation of Prestressed Concrete Bridge

通过分析混凝土强度、名义徐变系数、环境相对湿度、环境温度和预应力荷载等徐变参数的变异性及其概率统计特征,探明了徐变参数的随机扰动对混凝土徐变系数的影响规律。通过对跨径布置为85m+130m+85m的预应力混凝土连续梁桥进行徐变变形分析,明确了不同随机性徐变参数对预应力混凝土桥梁主跨跨中挠度的影响,获得了预应力混凝土桥梁10年期间的跨中挠度变异系数、均值及95%置信区间值。结果表明,徐变参数随机性对混凝土桥梁徐变系数具有重要的影响作用,通过控制随机性置信区间上下限值可达到控制混凝土桥梁长期变形的目的,研究成果具有重要的工程应用价值。

Variability and probability statistical characteristics of creep parameters which include concrete strength,nominal creep coefficient,relative humidity,temperature and prestress load were studied.The stochastic disturbance effects of creep parameters on the creep coefficient were analyzed.Based on a long-span prestressed concrete bridge with span 85 m＋130 m＋85 m,the different stochastic parameters influence on main span deflection of the prestressed concrete bridge were studied,and the mid-span deflection mean,standard deviation and 95% confidence interval of the bridge during 10 years were obtained.The results show that stochastic creep parameters have an important effect on the creep coefficient of concrete bridge.The mid-span deflection interval analysis of concrete bridge,to ensure the long-term deformation in the safe range,has important application value in engineering.