Experimental and numerical study on the mechanical performance of curved steel–concrete composite box girders is reported in this research. First, this research establishes a theoretical model for curved composite girders with 11° of freedoms (DOFs) for each node. The DOFs include the longitudinal displacement, transverse displacement, deflection, torsion angle, warping angle, and interface biaxial slip between steel and concrete. Based on the virtual work theorem, the equilibrium function, the stiffness matrix, the node displacement matrix and the external load matrix are proposed for the curved composite girders using the FE spatial discretization. Second, the authors conduct an experimental program on three large-scale curved composite girders with various interface shear connectors and central angles. The comparison between the developed finite beam element, the elaborate FE model and the test results indicates the developed finite beam element has an adequate level of accuracy in predicting the deflection, the torsion angle and the axial strain distribution of test specimens. Third, based on the developed finite beam element model, the effect of initial curvature, number of diaphragms, and the interface connector stiffness on the curved composite girder is examined. The simulation results showed that the initial curvature significantly contributes to the displacement and stress of composite girders. Applying more diaphragms can notably reduce the distortion angle and distortion displacement. The interface shear connector stiffness has a significant influence on the curved composite girder. With the increasing shear connector stiffness, the displacement and stress of curved composite girders decrease notably. Based on the parametric analyses, it is recommended to limit the central angle of simply supported composite girder below 45°, to apply an adequate number of diaphragms, and to design curved composite girders as fully shear connection specimens.

中文翻译：

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考虑到扭转，变形和双轴滑移的弯曲复合箱形梁的22 DOF有限梁单元

这项研究报道了弯曲混凝土组合箱梁的力学性能的实验和数值研究。首先，本研究建立了每个节点具有11°自由度（DOF）的弯曲复合大梁的理论模型。自由度包括钢和混凝土之间的纵向位移，横向位移，挠度，扭转角，翘曲角和界面双轴滑移。基于虚功定理，提出了基于有限元空间离散化的曲线复合梁的平衡函数，刚度矩阵，节点位移矩阵和外部荷载矩阵。其次，作者对具有各种界面剪切接头和中心角的三个大型弯曲复合大梁进行了实验程序。所开发的有限元单元，复杂的有限元模型与测试结果之间的比较表明，所开发的有限元单元在预测试样的挠度，扭转角和轴向应变分布方面具有足够的精度。第三，基于已开发的有限梁单元模型，研究了初始曲率，隔板数量和界面连接器刚度对弯曲复合梁的影响。仿真结果表明，初始曲率显着影响了组合梁的位移和应力。应用更多的膜片可以显着减少变形角度和变形位移。界面剪切连接器的刚度对弯曲的组合梁有很大的影响。随着剪切连接器刚度的增加，弯曲组合梁的位移和应力明显减小。基于参数分析，建议将简单支撑的组合梁的中心角限制在45°以下，应用足够数量的隔板，并将弯曲的组合梁设计为完全剪切的连接样本。