Behavior of Confined Headed Bar Connection for Precast Reinforced Concrete Member Assembly

Abstract

The mechanical performance of precast RC structures relies on the connections, especially the connections of steel bars, between precast RC members. Grouted sleeve splices and grouted spiral-confined overlap connections are widely used in engineering practice in China. Both of these two connection splices require on-site grouting. The process is concealed and invisible, leading to difficult on-site inspection. The unseen defects cause a challenge for detection and repair, which may impair the reliability of precast RC members’ behavior. This paper presents an RC member assembly connection with visible on-site construction quality-monitoring. The proposed confined headed-bar connection (CHBC) consists of two overlapping headed bars and confinement stirrup. With CHBC, the potential construction defects are diminished, and subsequently the construction quality as well as the reliability is upgraded. Experimental investigation on 18 CHBC specimens was carried out; the main parameters considered were overlap length and bar-head size. The failure modes, bearing capacity, stirrup strain development and bond versus slip response are studied. Working mechanism of CHBC is investigated in terms of bond behavior force and concrete compression force at head experimentally and numerically; distributive relationship of these two forces is revealed. The results show that for Φ12 reinforcement, a 90 mm overlap length under test parameters is adequate to reach headed bar ultimate strength in CHBC. Finally, a CHBC-bearing capacity prediction method is suggested based on the superposition method and strut-and-tie model theory.

Shear Tests on Subassemblies Representing the Single-Anchored Connection between Precast Concrete Wall Panels and Reinforced Concrete Frames

“…Among the studies similar to this study, many experiments have been conducted on steel stud connections in recent years. These studies have mainly conducted experiments on steel stud connections, comprising push-out tests and programs [19][20][21][22].…”

Special Issue “Reinforced Concrete: Materials, Physical Properties and Applications Volume II”

“…Another article [7] proposed a method for predicting the load-bearing capacity of a fixed head connection, which is used in precast concrete structures, in particular when connecting steel bars between precast elements. This research has high engineering and scientific value.…”