中文摘要：

为研究新、旧结构的混凝土收缩、徐变对混凝土桥梁横向拼接的影响，考虑上、下部结构共同工作，对不同加宽方案的预应力混凝土箱梁桥因收缩徐变引起的结构横向效应进行了分析。研究结果表明：是否考虑结构上、下部共同工作对拓宽桥梁结构的横向受力状态影响显著，且拼接后既有主梁内的横向和轴向效应远大于竖向效应；拼接后旧桥上、下部结构的承载力发生改变，实桥拼接后旧桥受力最不利墩柱的抗压承载力仅为拼接前的51％，箱梁跨中截面的抗弯承载力为拼接前的98％～108％，支座截面的抗弯承载力为拼接前的87％～96％；新旧结构上、下部结构共同工作效应及旧桥上、下部结构承载力的改变在这类桥梁加宽改造设计时应当考虑。

英文摘要：

To study the effects of concrete shrinkage and creep between existing and new structure on transverse splicing of existing concrete bridges, with the interaction between the bridge superstructure and substructure considered, the transverse effects resulting from concrete shrinkage and creep of a continuous concrete box girder bridge widened with different plans were studied. The results show that the interaction between the bridge superstructure and substructure influences the performance of widened existing bridges markedly; the transverse and axial effect have a much greater influence than the vertical one in the widened bridge girders; the capacities of superstructure and substructure in those existing bridges will change. The post- widening compressive capacity of a worst existing pier is only 51% of that before widening, while the bending capacity in vertical direction of the box girder at mid-span and support section is from 98% to 108% and 87% to 96% of that before widening respectively. The interaction and the capacity change should be considered during the widening of existing concrete bridges.