弹卡式连接预应力混凝土方桩接头受弯性能研究

Study on flexural behavior of prestressed concrete square pile connection joint with resilient clamping

为了解决混凝土预制桩现场拼接工作量大、施工不便等问题,创新性地研发了一种弹卡式连接预应力混凝土方桩连接接头。通过对3种常用实心方桩接头试件进行受弯性能足尺试验,研究该方桩接头的受弯承载力、变形延性以及破坏特征。结果表明:弹卡式连接预应力混凝土方桩接头试件的开裂弯矩、极限弯矩试验值均大于其桩身开裂弯矩、极限弯矩规范公式计算值;方桩接头试件的受弯破坏形式均为连接接头底部被拉开,弹卡连接件附近预应力钢棒或墩头被拉断;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的全过程,模拟得到的极限弯矩和跨中挠度与试验结果相接近。

In order to solve the problems of large workload and inconvenient construction of on-site splicing of precast concrete piles, a type of new prestressed concrete square piles connection joint with resilient clamping was developed. The full-scale flexural performance experiments of three kinds of commonly-used solid square pile connection joint specimens were carried out to investigate the flexural bearing capacity, deformation ductility and failure characteristics of the square pile connection joints. The results show that the experimental values of the cracking and ultimate bending moments of the prestressed concrete square pile connection joint specimens are larger than the calculated values of the cracking and ultimate bending moments of the pile body from the code formula. The flexural failure mode of the square pile connection joint specimens is that the bottom of the connection joint is pulled away, and the prestressed steel bar or pier head near resilient clamping connectors is broken. The established numerical model can well simulate the whole process of the square pile connection joint specimens from the loading to the failure, and the simulated ultimate bending moment and mid-span deflection are comparatively close to the experiment results.