灌浆缺陷对半灌浆套筒连接件强度的影响

Influence of Grouting Defects on Strength of Semi-Grouting Sleeve Connections

为研究半灌浆套筒连接件受灌浆缺陷影响的规律,对含端部、中部和均布灌浆缺陷及灌浆饱满的连接件进行单向拉伸试验,通过有限元软件分析研究灌浆缺陷类型和缺陷尺寸对连接件拉伸强度的影响。结果表明:灌浆缺陷导致半灌浆套筒连接件拉伸强度降低,相同尺寸的均布缺陷对C25连接件拉伸强度影响最大,中部缺陷次之,端部缺陷最小。随着灌浆缺陷长度的增大,含灌浆缺陷连接件的破坏形态均由钢筋拉断破坏转变为钢筋拔出破坏。并且,连接件屈服强度和极限抗拉强度的降低速率与灌浆缺陷类型相关,含均布缺陷的连接件降低最快,含端部缺陷的连接件最慢。为确保C25半灌浆套筒连接件满足I级接头要求,含端部、中部和均布灌浆缺陷的连接件钢筋最小锚固长度分别为125、150和175 mm。

To study the effect of grouting defects on tensile strength of semi-grouting sleeve connection,uniaxial tension tests were carried out on connections with end,middle and uniformly distributed grouting defects,together with fully grouted connections.The influences of the type and dimension of grouting defects on tensile strength of connections were additionally analyzed by finite element software.The results show that the presence of grouting defects degrades the tensile strength of semi-grouting sleeve connections.Moreover,the uniformly distributed grouting defect has the most negative effect on the tensile strength of C25 connections,followed by the middle defect,and the end defect is the least.With the increase of the defect's dimension,the failure modes of connections transform from the steel bar fracture to the grouting end pull-out.Additionally,the reduction rates of the yield strength and the ultimate tensile strength of connections are related to the type of grouting defects.The tensile property of connections with uniformly distributed grouting defects shows the most seriously degradation,and those with end defects show the slowest degradation.Finally,to meet the standard requirement of grade I joint for C25 semi-grouting sleeve connections,the minimum anchorage lengths of the connections with end,middle and uniformly distributed grouting defects are 125,150 and 175 mm,respectively.