考虑界面滑移效应的钢-混凝土组合梁新型非线性纤维梁单元模型

Novel Nonlinear Fiber Beam Element Model for Analysis of Steel-Concrete Composite Beam with Interface Slip Effect Considered

目的提出一种新型的考虑钢-混凝土组合梁界面滑移效应的非线性纤维梁单元理论模型,用于此类结构加载至破坏全过程中弹塑性力学行为的高效分析。方法根据钢-混凝土组合梁的结构特点,在传统纤维梁单元理论的基础上,引入钢梁与混凝土板之间的相对滑移变形模式,推导出考虑界面非线性滑移效应、钢梁与混凝土板材料非线性行为的新型纤维梁单元列式及迭代计算方法;并基于理论模型在OpenSees软件中进行新单元的嵌入式二次开发,再利用典型试验梁测试结果验证所建立理论模型及单元开发的有效性。结果笔者建立的单元理论模型对于弹性及弹塑性加载状态下的组合梁力学行为分析均具有很好的适用性,相较于试验结果,结构变形计算结果偏差在8.6%以内,承载力计算偏差在1.7%以内;界面滑移效应对钢-混组合梁的刚度及承载能力产生显著影响,对正弯矩抗弯承载力的影响程度高于负弯矩抗弯承载力。结论笔者所建立的单元理论模型和单元开发程序拓展了纤维梁单元的适用范围,为钢-混凝土组合梁考虑滑移效应的非线性力学行为分析提供了一种高效的计算方法。

A novel nonlinear fiber beam element model considering the interface slip effect of steel-concrete composite beam was proposed to analyze the elastoplastic behavior of such structures up to collapse.According to the structural characteristics of steel-concrete composite beams,the relative slip deformation mode between steel beam and concrete slab was introduced into the traditional fiber beam element.A new finite element formulation and iterative calculation method were derived to capture the nonlinear interface slip effect and the materially non-linear behaviors of steel beam and concrete slab.Then,the theoretical model was programmed in the OpenSees software as a newly developed element type.The effectiveness of the proposed model and developed procedure were fully verified with the reported tests and the elastic analytical solutions.Compared with the test results,the prediction deviations of the proposed model were within 8.6%for structural deformation and within 1.7%for structural capacity.The analysis results revealed that the structural stiffness and capacity were decreased with the weaker interface connection and the interface slip effect was non-negligible.The proposed model and developed program in this paper provided a high-efficiency analysis tool for the analysis of steel-concrete composite structures.