预制钢-混组合桥面板组装式连接静力及疲劳性能试验

桥梁建造由装配化向组装化的转换是未来桥梁工程发展的方向，钢-混组合桥梁是一种与工业化、组装化高度契合的结构形式；活性粉末混凝土等超高性能水泥基材料的应用为钢-混组合结构桥梁的轻型化和组装化提供了新的契机与挑战。提出基于高弹模和高韧性混凝土-粗骨料活性粉末混凝土的预制桥面板及板间组装式连接结构（CSL），从而减轻结构自重、改善预制桥面板间的连接性能，实现桥梁结构的组装化作业，提升桥梁的建造质量和速度。通过四点弯曲试验考察预制粗骨料活性粉末混凝土桥面板及其干式连接结构的结构行为，分析加载全过程挠度的发展特点，探明极限承载能力及疲劳性能。静力试验结果表明：通过CSL连接而成的桥面板具有优异的变形能力和弯曲韧性，破坏均发生在粗骨料活性粉末混凝土板内，CSL的抗弯极限承载力高于粗骨料活性粉末混凝土桥面板；CSL的钢混连接面处弯曲初裂应力值不小于9.0 MPa，接近粗骨料活性粉末混凝土的弯曲初裂应力，并具有良好的裂缝约束能力。疲劳试验结果表明：CSL中的钢结构应力幅较小，经过800万次疲劳加载后，CSL连接桥面板未发生疲劳破坏，桥面板间连接焊缝应力幅仅26.8 MPa，不会出现疲劳破坏；CSL中的预加力对连接结构的静动力性能具有重要影响。

Experiment on Static and Fatigue Performances of Assembled Concrete-steel Link in Assembled Composite Bridge Deck

Assembled bridge construction is a promising method for future bridge engineering. The steel-concrete composite bridge is highly accorded with the principle of assembled construction. Furthermore, the application of reactive powder concrete (RPC) provides additional opportunities and challenges for further optimization of this steel-concrete composite bridge design, i.e., reducing the self-weight and accelerating construction. In this study, a prefabricated composite bridge deck made of coarse aggregate RPC, which has high elastic modulus and high toughness, was developed. A new joint, called concrete-steel link (CSL) is proposed to connect the prefabricated composite bridge decks to reduce the self-weight, achieve satisfactory crack resistance performance, and realize fully assembled and accelerated construction. The structural performance-the characteristics of load-deflection relationship, ultimate bearing capacity, and fatigue performance-of the prefabricated bridge deck and the CSL were tested by the 4-point bending test. The results of the static tests show that this fabricated composite deck display high deformability, bending ability, and ductility. All the failure sections were located in the RPC panel, which indicates that the CSL has higher ultimate bearing capacity than the cast-in-place coarse aggregate RPC panel. By implementing the CSL, the initial cracking stress is higher than 9.0 MPa, and is located close to the coarse aggregate RPC stiffened plate. The fatigue tests show that the stress amplitude is low, and after 800 million cycles of harmonic loading, there is no fatigue fracture on the CSL. The stress amplitude of the weld seam is just 26.8 MPa. The prestress in CSL is the key factor for both the static and fatigue performances.