弹卡式连接预应力混凝土方桩接头抗拉性能研究

为了解决预制混凝土桩现场拼接工作量大、接头易腐蚀等问题,创新研发了弹卡式连接预应力混凝土方桩接头。通过单个弹卡连接件的拉伸试验以及3种常用桩型方桩接头试件的足尺度抗拉性能试验,研究该方桩接头的抗拉承载力、变形延性以及破坏特征。结果表明:单个弹卡连接件的极限抗拉承载力大于150 kN,涂满环氧树脂后其极限抗拉承载力、变形延性和整体性均有所提高;弹卡式连接预应力混凝土方桩接头试件的极限抗拉承载力试验值均大于其桩身极限抗拉承载力规范公式计算值;方桩接头试件的破坏形式有桩身受拉破坏和弹卡连接接头受拉破坏两种;建立的数值模型可以较好地模拟方桩接头试件从加载到破坏全过程,模拟得到的极限抗拉承载力与试验结果相接近。

Study on Tensile Behavior of Prestressed Concrete Square Pile Connection Joint with Resilient Clamping

In order to alleviate the heavy on-site splicing workloads and overcome the joint corrosion and other problems for precast concrete piles, the connection joint with resilient clamping was innovatively developed for prestressed concrete square piles. The tensile tests on single resilient clamping connectors and full-scale tensile tests on connection joint test specimens for three kinds of commonly-used square piles were conducted to investigate the tensile bearing capacity, deformation ductility and failure characteristics of the connection joints. The results show that the ultimate tensile bearing capacity of a single resilient clamping connector is larger than 150 kN, and the ultimate tensile bearing capacity, deformation ductility and integrity of the connector can be improved by filling the connector with epoxy resin. For the ultimate tensile bearing capacity of square piles, the experimental results of the connection joint test specimens are all greater than the calculated values of the concrete pile body using the code formula. There are two types of failure modes for the square pile connection joint test specimens: concrete pile body tensile failure and connection joint tensile failure. The established numerical model can well simulate the whole loading process of the connection joint test specimens, and the simulated values of ultimate tensile bearing capacity comparatively agree with the experimental results.