不同截面螺旋扭状钢筋的粘结锚固性能

Bond Anchorage Performance of Spirally Twisted Bar with Different Cross-section

将不同截面尺寸的螺旋扭状钢筋与对照组光圆钢筋、带肋钢筋一起进行了钢筋-混凝土粘结锚固拔出试验,分析了形成螺旋扭状钢筋Fs曲线第2峰值的机制,推测了截面特征系数与Fs曲线第2峰特征锚固强度值之间的关系.试验研究表明:形成螺旋扭状钢筋Fs曲线第2峰值的原因是由于该钢筋具有螺旋状表面的缘故;在螺旋节距不变的前提下,螺旋扭状钢筋横截面长边与短边长度之差值所控制的截面特征系数越大,则Fs曲线第2峰的峰值就越大,钢筋的粘结锚固延性就越好.

By means of a series of pull out tests on the concrete specimens of spirally twisted bars with different cross-sections, plain round bars as well as ribbed bars, the bond anchorage mechanism of spirally twisted bars was studied. It is found that the spirally twisted bars results in the second peak value which is much larger than the first peak value on pull-slip curve under a fixed spiral pitch, and the larger the difference value between the long side and the short side of cross-section is, the higher the second peak will be, and bond anchorage ductility of the bars will be better as well.