中文摘要：

为提高多梁式钢-混组合小箱梁的横向受力性能，针对横梁相对抗弯刚度小的特点，提出采用弹性支承连续梁法分析横梁受力的实用方法。将横梁比拟为弹性支承连续梁，用初参数法计算其反力影响线，鉴于箱形主梁抗扭刚度大，导出了支承反力的修正公式；进而为避免混凝土桥面板开裂，提出了在桥面引入横向预应力体系的处置方法，对1个简支钢-混组合桥的横向预应力进行了设计配筋，给出了相应的数值分析结果。研究结果表明：弹性支承连续梁法计算的横梁内力与有限元计算结果相比，两者控制截面结果误差一般在10％以内；未施加预应力时混凝土桥面板将出现过大的拉应力，施加横向预应力能改善混凝土板的横向受力，保证全跨混凝土板横向受压；横向预应力对结构的竖向挠度影响很小，不影响结构的整体变形。

英文摘要：

In order to improve lateral mechanical performance of multi-small box reinforced concrete composite girder, a practical method named continuous beam with elastic support （CBES） for analyzing transverse beam stress was proposed by considering that bending stiffness of transverse beam was relatively low. Transverse beam was simulated as a continuous beam with elastic support and reaction influence line was calculated by using initial parameter method. For stronger torsion stiffness of box beam, the modified formula of support reactions was also derived. A disposal method of introducing transverse prestressing in the concrete deck plate was presented in order to avoid cracking in deck plate. Reinforcement design for transverse prestressing of a typical simply-supported multi-small box composite girder bridge had been carried out and corresponding numerical analysis was conducted. The results show that stresses in transverse beam calculated by proposed method are compared with FEM results, which the error is within 10% for control sections of transverse beam. Larger tensile stresses in the concrete deck plate occur without prestressing. Applying transverse prestressing in the concrete deck plate can effectively improve lateral mechanical behavior and ensure that concrete deck is under compression in the whole span. Transverse prestressing has little effect on deflection without influencing global deformation.