组合连接件对钢管-混凝土黏结性能的影响

为了揭示组合连接件对钢管与外围混凝土工作性能的影响规律，开展由环板、加劲板、焊钉组成的组合连接件对钢管与外围混凝土的黏结滑移性能影响试验研究.获取界面黏结-滑移曲线以及裂缝的分布规律，并在试验的基础上开展数值模拟参数分析，并与规范计算结果进行对比.研究结果表明：带组合连接件钢管特征滑移量大于6 mm，符合欧洲规范Eurocode-4对延性连接件的要求；环板与加劲板组合能更充分地利用混凝土的抗压性能，配置一定比率的焊钉能有效提升界面弹性抗滑移刚度；增大焊钉率可以提升界面塑性抗滑移刚度、极限抗滑移强度，高焊钉率的多排焊钉并未改变焊钉作为延性连接件的性质；单个焊钉实际极限荷载值与规范计算值基本一致.
Abstract: The bond-slip experiments were conducted to reveal the influence of the composite connectors on the mechanical properties of the steel tube and the surrounding concrete. The composite connectors consist of annular plate, stiffening plate and welding nails between the steel pipe and the surrounding concrete. The bond-slip curves and the cracks distribution were obtained on the basis of the experiments. Then, the numerical simulation analysis was carried out and compared with the results of the standard calculation. Results show that the characteristic slip of the steel tube with the composite connectors is more than 6 mm, which meets the standard Eurocode-4 requirements for ductile connectors. The combination of annular plate and stiffening plate takes advantage of the compressive strength of the concrete sufficiently. The welding nails has improved the elastic anti-slip stiffness of the interface effectively. Increasing the ratio of welding nails can enhance the plastic anti-slip stiffness and ultimate strength of the interface, and welding nails of high ratio don't change the character of welding nails as the ductile connection. The actual ultimate load value of single welding nail is nearly consistent with the calculate value of the codes.