既有砌体结构墙体植筋拉拔性能的理论分析与试验研究

砌体结构的材料强度较低且砖墙是由砖块与砂浆两种材料复合而成，将植筋技术应用于砌体结构尚未有深入研究。基于锥体破坏、剪切破坏与黏结破坏这三种破坏模式，推导了与植筋深度、墙体强度相关的植筋拉拔承载力的半经验简化计算式；利用8处不同类型的既有砌体结构，针对不同植筋直径、植筋深度进行现场拉拔试验；采用有限元数值分析，对砖墙的植筋拉拔性能进行分析，结合现场拉拔试验的结果，验证了半经验简化计算式的合理性。通过以上理论分析、现场试验，对植筋技术在砌体结构中的应用提出以下建议：在砌体结构中采用植筋，砖墙砂浆的抗压强度应大于M2.0；植筋的直径建议采用6 mm、8 mm或10 mm即可；植筋深度介于100 mm与150 mm之间。

Theoretical analysis and experimental research of pull-out behavior of bonded steel bar embedded in brick wall of existing masonry structure

The brick wall is comprised of bricks and mortar. The strength of brick wall is low, so it is necessary to do some research on the mechanical property and the failure mode of steel bar embedded in the brick wall. In this paper, according to cone failure mode, shear failure mode and bond failure mode, the calculation formulas of the ultimate pull-out load are deduced. The semi-empirical simplification formula dependent on the strength of brick wall and the embedment depth, is also presented. Pull-out tests on steel bars with different dimension and depth were carried out in 8 masonry structures, which were different in the material strength and construction time. The finite element analysis (FEA) was also carried out. The results of pull-out test and FEA were compared to the results of theoretical analysis, which verified the rationality of the simplified formula. Some suggestions are presented as follows: the strength of mortar must be higher than M2.0, the suggested embedment depth is between 100 mm to 150 mm and the suggested diameters of steel bar are 6 mm, 8 mm and 10 mm.