套筒内腔构造对钢筋套筒灌浆连接黏结性能的影响

为研究套筒内腔构造对钢筋套筒灌浆连接黏结性能的影响，考虑套筒内腔环肋数量、间距、凸起高度等参数，制作了31组不同规格的钢筋连接试件，并进行了单调轴向拉伸试验和理论分析。结果表明：增加套筒环肋数量及内壁凸起高度，可提高钢筋套筒灌浆连接的承载力，减小钢筋屈服前的连接位移，但随着环肋数量和凸起高度的不断增加，内腔构造的变化对连接钢筋黏结性能的影响程度逐渐减小；套筒环肋每端不宜少于3道，内壁凸起高度应大于1.0 mm，并应分布在钢筋非弹性段长度内，在钢筋弹性段布置环肋或增大环肋凸起高度会削弱钢筋的黏结性能；基于试验得到的钢筋平均黏结应力，提出了钢筋非弹性段长度的计算方法。

Effect of sleeve inner cavity structure on bond performance of grouted pipe splice

Grout-filled pipe splice is one of the most important technology in precast construction. The splice bond performance directly influences the integrity and seismic performance of precast structure. In order to investigate the effect of inner cavity structure of sleeve on the bond strength of grouted pipe splice, considering different parameters of quantity, spacing and height of inner concentric ribs which are rolled on the sleeve, thirty-one groups of splice specimens were prepared and tested in this research. Through direct monotonic pullout test and theoretical analysis, it is shown that increasing the number and height of the rib can improve the tensile capacity of the grouted splice and also can decrease its displacement before yielding of the bar. However, with continuous increment of the number and height, the effects of variation of the inner cavity structure on the bond performance gradually decrease. The quantity of the inner ribs should not be less than three at each side of the sleeve, and the rib height should be greater than 1.0 mm. Meanwhile, the ribs should be distributed in inelastic segment of the steel bar, otherwise excessive ribs or higher rib height would impair the bond performance of spliced bar. Based on the experimental results of average bond stresses, a calculation method of the inelastic range was proposed. The calculated length is consistent with the test result.