中文摘要：

为分析大跨悬浇预应力混凝土连续刚构桥箱梁节段接缝对桥跨挠度的影响，建立了考虑施工全过程以及运营期长期变形的已建大跨预应力混凝土连续刚构桥的有限元模型，用抗剪刚度的降低模拟了箱梁节段接缝的弱化，重点分析了箱梁节段接缝弱化对成桥挠度和长期挠度的影响．分析结果表明，只有在接缝抗剪刚度大幅降低的前提下，箱梁节段接缝的剪切变形对桥跨结构的挠度才具有显著的影响，而接缝开裂后的抗剪刚度大小是决定影响程度的关键，节段接缝的剪切变形以及由此而引起的剪切徐变是否会造成大跨预应力混凝土箱梁持续下桡还有待于试验验证．

英文摘要：

In order to analyze the effect of segmental joints of box girder on structural deflection in long span cantilever casting prestressed concrete continuous rigid frame bridges, the FE models considering both construction processes and long-term deformations in existing bridges were established. Reduction in shearing stiffness was adopted to simulate weakness of segmental joints of box girder,and the effect of shearing deformations induced by weakness of segmental joints was analyzed. The results showed that the shearing deformations of segmental joints could lead to the significant increment in completed deflection and long-term deformation, only under the premise of remarkable decrease in shearing stiffness of segmental joints. In practical bridge structures, the determination of shearing stiffness of segmental joints after crack is a key problem for this effect. Whether or not the shearing deformation and shearing creep can contribute to continued deflection in long-span prestressed concrete box girder needs to be verified by enough experiments.