加载方式和锚固长度对钢筋套筒灌浆连接性能影响试验研究

EXPERIMENTAL STUDY ON EFFECT OF LOADING MODE AND ANCHORAGE LENGTH ON CONNECTION BEHAVIOR OF GROUTING SLEEVE FOR REBARS SPLICING

考虑三种加载方式(重复拉伸、高应力反复拉压、大变形反复拉压)与锚固长度(6.5d、7d、8d)对接头连接性能的影响,对40个试件进行拉伸试验,研究其破坏形态、力-位移关系曲线、应变分布等,分析该连接试件的约束机理与灌浆料裂缝开展过程,确定其光滑段与变形段的应力分布及钢筋临界锚固长度。结果表明:试件破坏模式包括钢筋拉断和螺纹端钢筋拔出破坏;循环荷载作用下,接头刚度退化严重;随钢筋锚固长度减小,试件耗能能力减小。套筒表面纵向与环向峰值应变位置和光滑段与变形段的黏结应力分布受钢筋锚固长度影响显著。钢筋直径为12 mm和20 mm的试件临界锚固长度分别为5.42和5.48倍钢筋直径。

This paper presented an experimental study on the mechanical properties of 40 steel grouted sleeve splices considering the effects of the loading modes(repeated tensile loading,repeated tensile and compression loading at high stress and repeated tensile and compression loading at large strain)and anchorage length(6.5 d,7d,8d).The failure modes,load-displacement curves,strain distribution,etc.were studied.The constraint mechanism of the connection specimens and the crack development process of the grouting material were analyzed.The stress distribution in smooth section and deformed section of the sleeve,and the critical anchorage length of the rebar were determined.The test results showed that the failure modes should include the rebar tensile failure and rebar pull-out at the threaded end.The rigidity degeneration of the splices was obvious under cyclic load.The energy-dissipating capacity of specimens decreased with the decrease in anchorage length.The longitudinal and circumferential peak strain positions on the sleeve surface and the bonding stress distribution between the smooth section and the deformed section were significantly affected by the anchorage length of the rebar.The critical anchorage lengths of rebar diameter of 12 mm and 20 mm were 5.42 and 5.48 times the rebar diameter respectively.