钢-ECC组合梁负弯矩区受弯性能试验研究

纤维增强水泥基复合材料（Engineered Cementitious Composite，ECC）具有高延展性以及受拉刚化特点，应用于组合梁桥的负弯矩区时可有效减少桥面板的受拉开裂。完成了2根钢-ECC组合梁和1根钢-混凝土组合梁对比构件在负弯矩作用下的静力加载试验，通过试验研究了不同配筋率的ECC对结构受力性能特别是抗裂性的影响。试验研究表明：在负弯矩作用下，钢-ECC组合梁的刚度较钢-混凝土组合梁明显提高|由于ECC翼板的抗拉作用导致截面中和轴上升，钢梁受压区增大，构件延性有所降低|钢-ECC组合梁可有效提高结构的开裂荷载并减小裂缝宽度，提高配筋率有利于进一步减少ECC翼板的裂缝宽度。提出了钢-ECC组合梁的承载力与开裂荷载的计算方法，提供了挠度分析的方法和裂缝宽度的基本模型。

Experimental research on negative bending behavior of steel-ECC composite beams

Engineered Cementitious Composite (ECC) has high ductility and characteristic of multi-micro-cracks under tension and shear loads. The concrete can be replaced with the ECC material in the steel-concrete continuous composite beam under negative moment to reduce the crack of concrete slab. The bending and cracking properties of steel-ECC composite beams are studied and compared . The experiments consist of 2 steel-ECC composite beams and 1 steel-concrete composite beams. The influence of reinforcement ratio on bending and cracking property is discussed. The study reveals that, when under negative moment, the rigidity of steel-ECC composite beam is higher than that of steel-concrete composite beam, while ductility decreases because of the effect of the ECC flange. Steel-ECC composite beams have excellent control over the development of the crack. Higher reinforcement ratio has better control over the crack. The method to calculate the bending capability and cracking load of steel-ECC composite beams is proposed. A basic model is put forward to calculate the deflection and crack width.