搭接长度对套筒灌浆搭接接头反复拉压力学性能影响试验

Mechanical Test of Sleeve Grouting Lap Connector with Different Lap Lengths Under High Stress Repeated Tension-compression Loading

摘要:

为研究高应力反复拉压时搭接长度对套筒灌浆搭接接头（APC接头）力学性能的影响，进行了32个APC接头的单拉及高应力反复拉压试验。结果表明：经过高应力反复拉压，试件承载力有所提高，而钢筋与灌浆料间的裂缝进一步发展，试件延性变小；随着搭接长度的增加，试件残余变形u₀（单拉）和u₂₀（高应力反复拉压）均减小；在单拉及高应力反复拉压结束后再单拉时，极限荷载下套筒中部截面近钢筋侧纵向压应变、环向拉应变随着搭接长度的增大而减小；基于灰色关联理论得出接头含钢率与极限黏结强度相关性最大。最后，引入灌浆缺陷系数ω，提出极限黏结强度、临界搭接长度计算式。

Abstract:

Uniaxial tensile tests and high stress repeated tension-compression tests for 32 specimens of sleeve grouting lap connectors named APC connector were conducted to study the effect of lap length on the mechanical properties of APC connector. It is shown that： after the high stress repeated tension and compression， the bearing capacity of the specimens is improved， while the ductility of the specimens is reduced due to the further development of the cracks between the steel bar and the grout； the residual deformation u₀ （single tension） and u₂₀ （high stress repeated tension and compression） of the specimens are reduced as the lap length of the specimens is increased； with the increase of lap length， the longitudinal compressive strain and hoop tensile strain of the middle section of the sleeve near the steel bar are reduced under the ultimate load state when the specimens are stretched under uniaxial tension and the last tensile part after repeated tension-compression loading； based on the gray relation analysis， the steel content of the connector has the greatest correlation with the ultimate bond strength. Finally， the ultimate bond strength and critical lap length formulas were put forward with the introduction of the grouting defect coefficient ω.