正交异性钢-混凝土组合桥面板纵桥向的压弯性能

针对传统正交异性钢桥面板疲劳开裂及沥青铺装破损桥梁工程两大难题，对有望应用于大跨度桥梁中的正交异性钢-混凝土组合桥面板的力学性能进行了试验及理论研究。为探究适用于组合梁斜拉桥的正交异性钢-混凝土组合桥面板纵桥向的受力性能，设计并制作了6个带U肋的正交异性钢-混凝土组合桥面板足尺试件，进行了轴向压力和弯矩加载试验，研究了不同轴向压力、不同混凝土等级对该组合桥面板受弯承载力、延性及塑性发展的影响，并提出了考虑轴压力影响的塑性抗弯承载力计算公式。研究结果表明：当轴向压力恒定时，组合桥面板在压弯荷载作用下的最终破坏形态均为跨中区域下部混凝土板的横向开裂及上部混凝土的压溃；轴压力对正交异性钢-混凝土组合桥面板的初始弹性抗弯刚度影响较小；不同轴压力下抗弯承载力降低值随着轴力的增大并未呈现显著递减趋势，这与轴向压力加载出现偏心距有关；轴压力会显著降低正交异性钢-混凝土组合桥面板的延性及塑性发展过程；将混凝土强度等级从C60提高到C80，并没有显著提高组合桥面板的初始弹性刚度、抗弯承载力、延性及延长其塑性发展过程；此外，提出的考虑轴压力影响的塑性抗弯承载力计算公式精度较高，可有效预测正交异性钢-混凝土组合桥面板的压弯承载力，为实际工程应用提供理论参考。

Longitudinal Compression-bending Performance of Orthotropic Steel-concrete Composite Bridge Deck

To prevent fatigue cracking of traditional orthotropic steel bridge decks and damage to asphalt pavement, experimental investigation and theoretical analysis were conducted on orthotropic steel-concrete composite bridge decks, which are expected to be applied in long-span bridges. To investigate the compression-bending performance of orthotropic steel-concrete composite bridge decks utilized in composite girder cable-stayed bridges, six single-point-loaded, simply supported orthotropic steel-concrete composite decks with varying axial compressive forces and concrete grades were designed and tested. The influence of axial compressive forces and concrete grades on the flexural capacity, ductility, and plastic development of the specimens were analyzed. Moreover, a formula for calculating the plastic flexural capacity considering the influence of axial compressive force was deduced. The test results show that the final failure modes of all specimens are transverse cracking of the lower concrete and crushing of the upper concrete at the midspan. Axial compression has a negligible effect on the initial elastic flexural stiffness, but it considerably lowers the ductility and plastic development of orthotropic steel-concrete composite decks under vertical load. The flexural capacity of the specimens does not exhibit a decreasing trend with increasing axial compressive force; this may be caused by the initial eccentricity of the axial compressive force. Improving the concrete grade from C60 to C80 does not appreciably enhance the elastic stiffness, flexural capacity, ductility, or plastic development of orthotropic steel-concrete composite decks. In addition, the proposed formula for calculating the plastic flexural capacity is highly accurate and could provide technical support for engineering applications.