新型灌浆套筒的约束机理及约束应力分布

郑永峰,郭正兴,曹江

(东南大学 土木工程学院,210096 南京)



摘要:

为降低预制装配混凝土结构中的钢筋连接成本,利用无缝钢管,采用冷滚压工艺研制了一种新型钢筋连接用灌浆套筒,通过接头单向拉伸试验,主要研究了套筒的约束机理及约束应力分布.结果表明：该新型接头能够满足JGJ107—2010规定的单向拉伸强度要求；套筒在灌浆料硬化阶段产生的初始约束应力与钢筋、灌浆料、套筒的力学特性及接头尺寸有关,并随灌浆料膨胀率的增加呈线性增长；套筒变形段对灌浆料的平均约束应力大于套筒光滑段,变形段约束主要来自内壁环肋处相互挤压力的径向分力,光滑段对灌浆料的约束取决于灌浆料劈裂变形的大小.

关键词:  预制混凝土结构  灌浆套筒  接头  约束机理  约束应力分布

DOI：10.11918/j.issn.0367-6234.2015.12.019

分类号:TU39.04

基金项目:国家科技支撑计划项目 (2011BAJ10B03).



Confinement mechanism and confining stress distribution of new grouting coupler for rebars splicing

ZHENG Yongfeng, GUO Zhengxing, CAO Jiang

(School of Civil Engineering, Southeast University,210096 Nanjing, China)

Abstract:

The novel grouting coupler was developed using seamless steel pipe through cold rolling press to reduce the cost of rebars splicing used in precast connection. Based on incremental tension test, the confinement mechanism and distribution of confining stress in the sleeve were studied. It is shown that the ultimate strength of this new splice can meet the regulation specified in JGJ107—2010. The initial confining stresses caused during the hardening process of the infilled grout are related to the mechanical properties of the spliced bars, grout and sleeve and dimensions of the splice. When these parameters are determined, the confining stress increased linearly with the increment of free expansion rate of the grout. The average confining stress in the deformed part is greater than it in the smooth part. For the deformed part, the confinement is mainly provided by the radial component of the interaction between the concentric ribs and the infilled grout. On the other hand, the confining stress in the smooth part is controlled by the dilation of the inner grout.

Key words:  precast concrete structure  grouting coupler  splice  confinement mechanism  distribution of confining stress