钢-混凝土组合梁在桥梁结构中应用广泛，车辆荷载会造成组合梁疲劳损伤的不断累积，从而对结构安全产生不利影响。为了研究疲劳损伤对钢-混凝土组合梁受力性能的影响，对7根组合梁试件开展了单调静力加载试验，其中5根组合梁试件在开展静力试验前经历了100万次的等幅疲劳加载。试验结果表明：在经历100万次的疲劳加载后，疲劳损伤会导致组合梁的极限变形能力降低，但组合梁的延性系数仍大于4.6，最终破坏形态均属于弯曲破坏；疲劳加载使钢材发生了强化效应，组合梁的屈服荷载均有所提高；部分抗剪连接组合梁的极限承载能力普遍降低，最大降幅约为初始极限承载力的7.3%；在抗剪连接程度相同的情况下，采用直径13 mm或16 mm栓钉对组合梁的极限承载力无明显影响。

Steel-concrete composite beams are widely used in bridge structures and fatigue damage caused by vehicle loads will accumulate gradually, which is adverse to the structure safety. To study the influence of fatigue damage on the mechanical performance of steel-concrete composite beams, monotonic static tests were conducted on seven composite beams, including five composite beams previously suffered 1,000,000 cycles of constant amplitude fatigue loading. Experimental results indicated that fatigue damage due to 1,000,000 cycles of fatigue loading caused the reduction of ultimate deformability of the composite beams. However, the ductility coefficients were still greater than 4.6 and the final failure patterns belonged to flexible failures. Fatigue loading led to the strengthening effect of steel material and the yielding loads of the composite beams improved correspondingly. The ultimate bearing capacities of the composite beams with partial shear connection generally reduced and the maximum drop reached 7.3% of the initial ultimate bearing capacity. Using studs with 13mm or 16mm in diameter has no significant effect on the bearing capacity of the composite beams when they possess the same shear connection degree.