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调查了受负弯矩和轴向压缩共同作用下钢-混凝土组合梁结构的性能。在这项研究中,对6个承受负弯矩作用的足尺寸的组合梁同时进行压缩。轴向压缩的等级由低到高变化。根据试验,构建并标定一个非线性有限元模型来对试验结果进行验证。该模型能够对试验所用梁的非线性响应和最终破坏模式做出预测。所构建的有限元模型对一些常在实际中使用的组合梁可进行一系列参数分析。分析发现,当压缩荷载作用于组合截面时,组合梁的负弯矩承载能力明显降低,钢梁的局部屈曲更显著,影响了截面的延展性。基于截面平衡的刚塑性分析可以合理地预测组合截面的复合强度,因此可适当地使用于设计原理中。在负弯矩区钢梁腹板处使用纵向加劲肋可消除腹板屈曲,并增加组合截面的转动能力。根据试验结果和有限元分析提出一个可应用于工程实践中的简化设计模型。
The behavior of steel-concrete composite beams subjected to negative bending moment and axial compression was investigated. In this study, six full-size composite beams subjected to negative moments were simultaneously compressed. The level of axial compression varies from low to high. According to the experiment, a nonlinear finite element model was constructed and calibrated to verify the test results. The model can predict the nonlinear response and the ultimate failure mode of beams used in the experiment. The finite element model is constructed for a series of parametric analysis of some commonly used composite beams. The analysis shows that when the compressive load acts on the combined section, the bearing capacity of composite beam decreases obviously, and the local buckling of the steel beam is more significant, which affects the ductility of the section. Rigid-plastic analysis based on section balance can reasonably predict the composite strength of the combined sections and therefore can be suitably used in design principles. The use of longitudinal stiffeners at the webs of negative moment regions eliminates web buckling and increases the ability of the combined section to rotate. According to the experimental results and finite element analysis, a simplified design model that can be applied in engineering practice is proposed.