摘要
针对预制构件套筒灌浆连接中混凝土-灌浆料-混凝土双界面的受剪性能,考虑界面粗糙度、配筋率、套筒灌浆料饱满度和灌浆层厚度等参数,通过22个Z形试件直剪试验,分析了受剪界面的破坏形态、抗剪强度、抗剪刚度和剪力-滑移曲线的变化规律。结果表明:双界面的剪切裂缝始于黏结界面,沿界面规则发展且剪断键槽后贯穿灌浆层;在弹性阶段和弹塑性阶段,剪力由黏聚力、钢筋摩擦力和销栓力平衡,剪切裂缝贯通后仅钢筋受剪;增加界面粗糙度、配筋率和灌浆层厚度,能提高双界面的极限剪力和抗剪刚度,而套筒灌浆料缺失65%,使极限剪力和残余剪力分别降低约10%和15%,抗剪刚度降低20%。基于剪力-滑移全曲线特征点性能参数,建立了双界面剪力-滑移本构模型,确定了不同界面粗糙度影响的黏聚力和摩擦系数;并基于弹性地基梁理论推导了灌浆层厚度影响的钢筋销栓力表达式,建立了不同因素影响下的双界面受剪承载力计算式,计算结果与试验结果吻合较好。
In this paper,direct shear tests were conducted on 22 Z-shaped specimens to analyze the shear performance of the concrete-grout-concrete double interface in the grouted sleeve connection of precast components.The failure modes,shear strength,shear stiffness,and shear-slip curve variations of the shear interface were examined.Several parameters such as interface roughness,reinforcement ratio,fullness of sleeve grouting,and grout layer thickness were considered in the tests.It is shown that the double-interface shear cracks start at the bonding interface,develop along the interface regularly and run through the grout layer after cutting the keyway.In the elastic and elastoplastic stages,the shear force is balanced by the cohesion force,the bar friction force and the pin force,and only the bars provide the shear resistance after the cracks penetrates.The ultimate shear and shear stiffness of the double interface are improved by increasing the interface roughness,reinforcement ratio and grouting thickness.The ultimate shear strength,residual shear strength,and shear stiffness are reduced by about 10%,15%and 20%with the absence of 65%sleeve grouting material,respectively.Based on the performance parameters of the characteristic points of the shear-slip curve,a two-interface shear-slip constitutive model was established.The cohesive force and friction coefficient affected by different interface roughnesses were determined.Based on the theory of beams on elastic foundation,the expression of pin force influenced by the thickness of the grout layer was derived.Finally,the calculation formula for double-interface shear bearing capacity under different factors was established,and the calculated results matched well with the experimental data.
作者
秦朝刚
高志尧
杨龙
吴涛
QIN Chaogang;GAO Zhiyao;YANG Long;WU Tao(School of Civil Engineering,Chang’an University,Xi’an 710061,China)
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2024年第12期223-235,共13页
Journal of Building Structures
基金
国家自然科学基金项目(51908042)
中国博士后科学基金项目(2019M660051XB)
陕西省自然科学基础研究项目(2023-JC-YB-326)。
关键词
预制混凝土
灌浆料
双界面
直剪试验
剪力-滑移曲线
抗剪强度
precast concrete
grouting concrete
double-interface
direct shear test
shear-slip curve
shear strength
作者简介
秦朝刚,出生于1989年,男,工学博士,副教授,主要从事新型装配式混凝土结构的研究。email:qinchaogang@chd.edu.cn。
