温湿变化对三塔结合梁斜拉桥徐变效应的影响研究

根据欧洲混凝土规范CEB-FIP 1990徐变计算公式,运用VB语言编写了考虑温湿度变化的徐变系数计算程序,嵌入武汉二七长江大桥有限元模型中,研究温湿度变化环境下主梁的变形和内力变化特征,获得温湿变化对三塔结合梁斜拉桥徐变效应的影响作用.研究结果表明：温度升高,混凝土徐变增大,钢主梁长期挠度也增大；相对湿度增加,混凝土徐变减小,钢主梁长期挠度也减小；一季度温度较低、湿度较大,温湿度同时变化时混凝土徐变较小,此时吊装混凝土桥面板引起的钢主梁挠度和应力值也较小,可见混凝土桥面板的吊装宜选择在温度低、湿度大的季节进行.

Study on the Creep Effect of Composite Girder Cable-stayed Bridge with Three-tower Under the Changing Temperature-humidity

According to European concrete standard CEB-FIP model code（1990）,a utility program of creep was compiled by VB Language inflection in this paper.The finite element model of Erqi Yangtze River Bridge was established,which was to research of the law of defection of main girder caused by the variety of temperature-humidity,and to obtain the creep effects of cable-stayed bridge with three towers caused by the variety of temperature-humidity.The results show that the deflection of main girders decrease as the humidity increases and increases as the temperature rises.When the temperature and humidity change at the same time,the deflection and stress of the main girder are also the smallest because of a quarter with lower temperature and humidity.Therefore,the concrete slab should be lifting during the time with lower temperature and higher humidity.The study could provide reference for choosing the reasonable hoisting time of the concrete slab and reducing the creep effect of concrete of composite girder bridge.