对钢-混凝土组合梁的长期变形问题进行了分析和讨论。指出我国现行（钢结构设计规范）关于组台梁长期变形的计算值偏小。并建立了组合梁的长期剐度计算公式。反映了混凝土徐变系数大小的影响。同时还考虑了混凝土收缩对变形的影响。公式意义明确。形式简单，应用方便。

本文结合某会展中心的大跨楼盖结构设计，介绍了大跨交叉钢-混凝土组合梁系楼盖的主要设计思路及构造方法，并介绍了复杂节点的构造措施。通过跨高比、用钢量等技术指标说明应用大跨交叉钢-混凝土组合梁系楼盖具有显著的技术经济效益。工程实践表明，这种大跨楼盖结构应用前景广阔。

Compared with simply supported beams, continuous steel-concrete composite beams have many advantages such as higher span/depth ratio, less deflection, and higher fundamental frequency of vibration due to its higher stiffness. However, in negative bending regions near interior supports, tension in concrete is unfavorable and a complicated issue, which deserves a special study. In this paper, a mechanics model based on elastic theory was established to investigate the stiffness of composite beams in negative bending regions by considering slips at the steel beam-concrete slab interface and concrete-reinforcement interface. In order to validate this approach, a test of three composite beams with profiled sheeting under negative bending was conducted. Meanwhile, a three-dimensional nonlinear finite element (FE) analysis was conducted to investigate the general behavior of the tested specimens. In addition, a comparative analysis between results derived from the analytical model, laboratory test, and FE analysis was performed. The results show that slip always exists for composite beams under negative bending even with complete shear connection (full composite action) between the steel and concrete components. The slip effect results in an additional curvature of beam bending and reduces the section stiffness by 10-20% compared with that of a beam without any slip in serviceability condition. This reduction should be considered in designing process especially for cantilever beams. Formulae under other loading cases and boundary conditions were also proposed. The results can serve as a basis for further study on stiffness of continuous steel-concrete composite beams and can directly be used for the deflection calculation of cantilever beams.

The present study investigated the effects of shear slip on the deformation of steel-concrete composite beams. The equivalent rigidity of composite beams considering three different loading types was first derived based on equilibrium and curvature compatibility, from which a general formula to account for slip effects was then developed. The predicted results were compared with measurements of six specimens tested in the present study and other available test results for both simply supported and continuous beams. It was found that including slip effects has significantly improved the accuracy of prediction. For typical beams used in practice, shear slip in partial composite beams has a significant contribution to beam deformation. Even for full composite beams, slip effects may result in stiffness reduction up to 17% for short span beams. However, slip effects are ignored in many design specifications that use transformed section method except that American Institute of Steel Construction (AISC) specifications recommend a calculation procedure in the commentary. In the AISC procedure, stress and deflection calculations of partially composite girders are based on effective section modulus and moment of inertia to account for slip, while ignoring slip effects in full composite sections. For full composite sections, the effective section modulus and moment of inertia calculated with the AISC specifications are larger than that of present study, meaning that the specifications are not on the conservative side. For partial composite sections, the AISC predictions are more conservative than the present study.

为研究钢-混凝土组合梁在不同加载方式下的受扭性能，完成了6根钢。混凝土组合粱的弯扭试验和纯扭试验，其中2根粱的扭矩直接作用于工字钢粱上，其余4根粱则由锕粱和混凝土翼绿板作为整体共同受扭。试验结果表明。当扭矩 直接作用于钢粱上时，混凝土翼缘板通过栓钉对钢粱的扭转提供约束，从而使钢粱的抗扭承载力比纯钢梁的提高2倍以上。在试验参数相同时，混凝土翼缘板和钢粱作为整体复合受扭时组合粱的开裂扭矩及极限抗扭承载力比扭矩直接作用于钢粱时的分别提高86%和39%。分析了两种不同加载方式下钢。混凝土组台粱受扭和受弯承载力的变化。建立了扭矩直接作用于钢梁上时极限扭矩的计算模型及计算公式。时整体受扭时组合粱的弯矩相关性进行了分析，并建立了相关曲线公式。计算结果与实测值吻合较好。