先张法预应力混凝土竹节管桩抗弯性能试验研究

Flexural Performance Experiment of Pretensioned Spun Nodular Concrete Piles

为研究竹节管桩的抗弯性能,以两种桩型的竹节管桩为例,按桩身外径计算得到了其开裂弯矩和极限弯矩,并进行了竹节管桩试件的开裂弯矩、极限弯矩、破坏特征及裂缝分布等抗弯性能试验研究,对比分析了计算值和试验值。结果表明:竹节管桩采用桩身直径计算抗弯性能较合理,试验值与理论计算值相比,极限弯矩的富余较大;竹节管桩的破坏形式为受拉区预应力钢筋首先发生屈服,然后受拉区预应力钢筋被拉断,最后受压区混凝土被压碎;竹节管桩跨中截面应变分布基本符合平截面假定,竖向裂缝出现后截面中性轴上移,受压区混凝土应变稳定增长。

In order to study the flexural performance of the pretensioned spun nodular concrete pile,the theoretical cracking moment and ultimate bending moment of two types of piles were obtained with reference to the outer diameter of the pilet,and the experimental research on the flexural performance such as cracking moment,ultimate moment,failure characteristics and crack distribution were carried out.The results show that it is reasonable to use the diameter of the pile body to calculate the flexural performance of nodular concrete pile,and the surplus of the ultimate bending moment between the experimental value and the theoretical value is larger.The failure characteristics of nodular concrete pile are as follows:the prestressed reinforcement in tension zone yields first,the prestressed reinforcement in tension zone is broken,and finally the concrete in compression zone is crushed.The results conforms to the assumption of plane section.After the occurrence of vertical cracks,the neutral axis of the section moves up,and the strain of the concrete in the compression zone increases steadily.