In order to analyze the influence position of prestressed reinforcement on the cracking load of composite girders, scale test and finite element analysis is used to study the cracking behavior of prestressed composite beam at the negative moment zone. The load–deflection curve and the cracking law of the scaled beam are obtained from the experimental results. The influence law of the resultant point and the spacing change through the symmetrical axis of the prestressed beam on the cracking load is obtained through the finite element parametric analysis. Furthermore, the prototype beam's mechanical performance in terms of the scaled test data is verified by both similarity theory and the prototype beam's numerical model. The results show that: Under different prestress levels, the cracking load is larger when the resultant force point of prestressed reinforcement on one side of the concrete slab's symmetric axis is within 0.15 ~ 0.50 times of slab half-width. In addition, the cracking moment of the specimen can be increased up to 11% by optimizing the prestress arrangement.

为了分析预应力筋对组合梁开裂荷载的影响位置，采用比例试验和有限元分析方法研究了预应力组合梁在负弯矩区域的开裂性能。从实验结果中可以得到伸缩梁的荷载-挠度曲线和开裂规律。通过有限元参数分析，得出了预应力梁对称轴上合点和间距的变化规律对裂纹荷载的影响规律。此外，通过相似性理论和原型梁的数值模型，验证了原型梁在按比例缩放的测试数据方面的机械性能。结果表明：在不同的预应力水平下，当预应力钢筋在混凝土板对称轴一侧的合力点在板半宽度的0.15〜0.50倍以内时，开裂荷载较大。此外，通过优化预应力布置，可以将试样的破裂力矩提高到11％。