UHPC节段梁键齿胶接缝抗剪性能试验研究

Experimental Study on Shear Behavior of Key Tooth Adhesive Joints of UHPC Segmental Beam

摘要:

为研究预制UHPC（Ultra High Performance Concrete，UHPC）节段梁间胶接缝在剪切荷载下的力学性能，开展了一组UHPC单键齿胶接缝和七组UHPC多键齿胶接缝抗剪性能试验，考虑键齿数量，键齿形式（高深比），胶层厚度和正应力水平对剪切荷载下UHPC多键齿胶接缝破坏过程，破坏模式和承载能力的影响。结果表明：UHPC多键齿胶接缝均在极限荷载的0.6～0.7的范围内出现开裂，键齿数量、正应力水平和键齿形式（高深比）对UHPC多键齿胶接缝抗剪性能的影响较大，增加键齿数量，提高正应力水平，采用高深比较大的键齿形式均能在不同程度上提高UHPC多键齿胶接缝的抗剪承载力和延性；胶层厚度对UHPC多键齿胶接缝抗剪性能的提升影响较小；考虑键齿折减效应的计算公式能够较为准确的预测UHPC多键齿胶接缝的抗剪承载力。

Abstract:

To study the mechanical properties of adhesive joints between prefabricated UHPC segmental beams under shear load, the shear behaviors of one group of UHPC single-key tooth adhesive joints and seven groups of UHPC multi-key tooth adhesive joints are tested. The effects of the number of key teeth, the form of key teeth (height-to-depth ratio), the thickness of adhesive layer and the normal stress level on the failure process, failure mode and bearing capacity of the UHPC multi-key adhesive joint under shear load are considered. The results show that the UHPC multi-key tooth adhesive joint cracks in the range of 0.6~0.7 of the ultimate load. The number of key teeth, the normal stress level and the form of key teeth (height-to-depth ratio) have the great influence on the shear behavior of UHPC multi-key toot adhesive joints. Increasing the number of keys, raising the normal stress level and choosing the form of key teeth with the larger height-to-depth ratio can improve the shear bearing capacity and ductility of UHPC multi-key tooth adhesive joints. The thickness of adhesive layer has little effect on the improvement of shear behavior of UHPC multi-key tooth adhesive joints. The calculation formula considering the deduction effect of key teeth can accurately predict the shear bearing capacity of UHPC multi-key tooth adhesive joints.