内置楔形体灌浆套筒连接接头力学性能试验研究

EXPERIMENTAL STUDY ON MECHANICAL PROPERTIES OF BUILT-IN WEDGE GROUT-FILLED SLEEVE SPLICE

采用无缝钢管加工了两种低成本灌浆套筒,并制作了22个钢筋连接接头试件,试件变量因素有连接钢筋锚固长度、连接钢筋直径、套筒类别及楔形体长度,通过静力拉伸试验对其力学性能进行了探究。研究结果表明:试件发生钢筋拔出和钢筋断裂两类破坏形式,但发生拔出破坏试件的残余承载力较高;增加连接钢筋锚固长度,试件承载力提高;增大连接钢筋直径后接头黏结强度和承载力提高;所有发生钢筋断裂破坏的试件的极限承载力均略低于相同直径钢筋在材性试验中测得的极限承载力;套筒内腔构造对套筒的受力性能有一定影响;楔形体长度和斜度均对套筒接头承载力有影响;两类套筒均在钢筋较小锚固长度下满足JGJ 107—2016《钢筋机械连接技术规程》中规定的Ⅰ级接头强度要求。最后通过回归分析提出了两个方程分别用于预测两类套筒的黏结强度,预测结果与试验结果吻合良好。

Two kinds of low-cost grouted sleeves were processed by seamless steel pipe,and 22 specimens of rebar splice specimens were made. Variables of the specimens were the length of the anchorage,the diameter of the spliced bar,the type of sleeve and the length of the wedge. The mechanical properties of the specimens were studied by static tensile test. The results showed that the failure modes of steel bar pull-out and rebar fracture occured,but the residual bearing capacity of the specimen with pull-out failure was higher. The bearing capacity of the specimens was improved by increasing the anchoring length of the spliced bar. The bond strength and bearing capacity of the joint increased after increasing the diameter of the connecting bar. The ultimate bearing capacity of all specimens with fracture failure of steel bar was slightly lower than that of steel bar with the same diameter measured in the material property test. The inner cavity structure of the sleeve had a certain influence on the mechanical behaviour of the sleeve. The bearing capacity of sleeve joint was affected by the length and slope of wedge. In addition,the two types of the sleeves could meet the strength requirements of the gradeⅠjoint under the specification JGJ 107—2016 in the small anchorage length of the steel bar. Finally,through regression analysis,two equations were proposed to predict the bond strength of the two types of sleeves respectively,and the predicted results were in good agreement with the experimental results.