中文摘要：

以一典型简支多梁式组合小箱梁桥为研究对象,将横梁近似视作支承在多片主梁上的多跨弹性支承连续梁,在混凝土板和钢梁间无相对滑移的平截面假定下,推导综合考虑混凝土收缩徐变作用的组合小箱梁在横向施加预应力下的横梁内力、横向长期应力和变形的计算公式,并将理论计算值和有限元软件MIDAS计算值对比分析。结果表明,两者吻合良好;在长期荷载作用下,结构挠度不断增加,预应力的施加能降低长期附加变形量以及横梁长期应力变化幅度;同时发现MIDAS会低估混凝土收缩徐变以及预应力筋松弛对这类组合梁桥横向长期附加应力的影响.

英文摘要：

Taking a typical simply-supported multi-box composite girder bridge as research object, the transverse beam was assumed as multi-span continuous beam which is elastically supported on the longitu- dinal main girders. Under the assumption of none slippage between concrete plate and steel girder, calcula- tion formula of lateral internal forces, long-term stresses and deformation were deduced considering trans- verse prestress and shrinkage and creep effect of concrete in the multi-box composite bridge. In addition, theoretical values were compared with FEM results by Midas/Civil. The results show that theoretical val- ues are identical with FEM results. Under long-term load, bridge deflection continuously increases and transverse prestress can decrease long-term additional deformation and variation range of long-term stres- ses in transverse beam. Results gained by Midas underestimate the influence of concrete shrinkage, creep effect and prestressed tendon relaxation on long-term additional transverse stresses in the multi-box com- posite bridges.