大跨径连续刚构挠度控制与影响因素研究

针对预应力混凝土连续刚构桥梁挠度问题，采用室内试验和模型分析混凝土收缩徐变和预应力损失对结构挠度变形的影响。结果表明：混凝土徐变增长会导致桥面纵坡坡度变化，结构应力重分布。混凝土前期徐变系数增长快，持荷40d的徐变系数为1．004，180d时增幅仅为2．988％。桥梁顶板预应力损失对结构挠度变形影响比底板更明显，顶板预应力损失为20％时，运营两年的挠度增幅达67．5％。因此，混凝土结构物受荷加载不宜过早，对结构的挠度进行控制有利于提高桥梁的安全性能。

Study on Deflection Control and Influential Factors of Long- span Consecutive Steel Bridges

The main research content of this article is the deflection problem of pre - stressed concrete continuous steel bridges. It used laboratory experiments and models to analyze influence to structural deflection of concrete shrinkage and creep and pre - stress loss. The results showed that： The addition of concrete creep will lead to deck longitudinal slope changes and structural stress redistribution. The preliminary creep coefficient of concrete is growing extremely fast. The creep coefficient of holding charge 40d is 1. 004, and it increased only 2. 988% when holding charge 180d. The pre - stress loss of the bridge top plate will lead to a much greater impact of structural deflection than backplane. When the pre - stress loss is 20%, the deflection is increases 67.5% after two years operation. Accordingly, concrete structures imposed load can not be prematurely and reasonable control of the structure deflection will help to improve the safety performance of the bridge.