单向拉伸荷载下堆焊成型套筒灌浆连接性能试验研究

Experimental study on performance of grouted sleeve connection with surfacing forming under uniaxial tensile load

为研究套筒灌浆连接的力学性能、工作机理以及套筒内腔构造参数对其力学性能的影响规律,采用堆焊成型套筒及开槽钢筋制作了21个不同参数的接头试件,并进行单向拉伸试验。结果表明:试验范围内接头试件钢筋临界锚固长度在5d和6d(d为钢筋直径)之间,锚固长度小于临界锚固长度时,钢筋发生刮犁式拔出破坏,大于临界锚固长度时,钢筋发生拉断破坏;钢筋应变从套筒端部向套筒中间逐渐减小,套筒轴向应变从套筒端部向中间逐渐增大;套筒端部呈现膨胀,中部呈现径缩;减少套筒内部环肋后,接头试件发生应力重分布,大部分钢筋拉伸荷载由套筒端部有环肋段承担;在锚固长度相同条件下,随着环肋间距减小,接头承载力有所提高,当间距减小到一定程度后其效果钝化;套筒内径变化对接头承载力无明显影响。

In order to study the mechanical properties and working mechanism of the grouted sleeve connection,and the influence of the inner cavity parameters on its mechanical properties,21 splice specimens with different parameters were designed and manufactured by using the sleeves with surfacing welding and slotted rebars,and the uniaxial tensile tests were carried out.The results show that the critical anchorage length is between 5d and 6d(d is the diameter of rebar).If less than it,the rebar will be pulled out in scraping plough type.If larger than it,the rebar will show tensile failure.From the end to the middle of the sleeve,the axial strain of rebar decreases,while the axial strain of the sleeve increases.The end of the sleeve expands and the middle of the sleeve shrinks.After reducing the concentric ribs inside the sleeve,the stress redistribution occurs in the splice specimen,and most of the tensile load of the rebar is beared by the sleeve end section with rib.When the anchorage length is the same,the bearing capacity of the splice increases with the decrease of the rib spacing.When the spacing is reduced to a certain extent,the effect is no longer significant.The change of the inner diameter of the sleeve has no obvious effect on the bearing capacity of the splice.