不同配筋形式矩形截面钢筋混凝土梁的弯曲性能及损伤机制的试验研究

Experimental research on the bending performance and damage mechanism of rectangular section reinforced concrete beams with different reinforcement forms

采用四种不同配筋率和两种不同配筋形式,进行了8根钢筋混凝土梁的四点弯曲试验,探究了不同配筋率和配筋形式下钢筋混凝土梁的弯曲性能及损伤机制。试验结果表明,钢筋与混凝土粘结面积更大的配筋形式可以增加试验梁的平均裂缝密度,降低裂缝宽度,让裂缝发展导致的刚度衰减更为均匀。相同配筋率条件下粘结面积更大的配筋形式可以大幅减小试验梁破坏时的跨中挠度,但对于较高配筋率的试验梁,过高的粘结应力可能产生脆性的斜截面破坏。随着配筋率的增长,梁抗弯极限荷载明显提高,剪跨区的斜裂缝发展逐渐占据主导。

The four-point bending tests of eight reinforced concrete beams including four different reinforcement ratios and two different reinforcement forms were performed,and the bending performance and damage mechanism of reinforced concrete beams under different reinforcement ratios and reinforcement forms are investigated.The test results show that the reinforcement form with larger bond area between reinforcement and concrete can increase the average crack density of the test beam and reduce the crack width,therefore the stiffness degradation caused by crack development is more uniform.The reinforcement form with larger bonding area can significantly reduce the mid-span deflection displacement when the reinforcement ratio is the same.However,for the beam with higher reinforcement ratio,excessive bonding stress may cause brittle inclined section failure.With the increase of reinforcement ratio,the ultimate load of the test beam is significantly improved,and the oblique cracks dominate gradually in the shear span area of the beam.