Mechanical Analysis of Grouted Sleeve Lapping Connector

Abstract

Compared to grouted splice connectors that have been widely used in constructing precast concrete structures, grouted sleeve lapping connectors have the advantages of a large sleeve interior diameter and low manufacturing cost. In this study, 16 grouted sleeve lapping connectors and three grouted splice connectors were tested under an incremental tensile load. The differences in their tensile capacities and failure modes, especially the mechanical properties of the grouted sleeve lapping connectors, were investigated. It was found that the tensile capacities of the grouted sleeve lapping connectors were up to 2.45 times that of the grouted splice connectors when the sleeve inner surfaces were smooth. All of the grouted sleeve lapping connectors failed by a bar tensile fracture or bar-grout slip, whereas the only failure mode of the grouted splice connectors was grout-sleeve failure. The bond stress distribution around the inserted bar in the grouted sleeve lapping connector was similar to the bond stress distribution around a single bar anchored in concrete. The ultimate hoop compressive strain of the sleeve and the corresponding load increase with greater lap length. In addition, an approximate mechanical model with high reliability was put forward to describe the mechanical properties of the grouted sleeve lapping connector.

The Bond Strength on Over Lapping Bars Using Pullout Test

“…The stress that occurs in the short and long lap spliced is a different; the stress value along short lap spliced tends to be the same. The bond stress of each bar at the lap spliced, the most significant number occurs on the side of the reinforcement pulled, then the smaller the middle and equal to zero at the free end [6], [25], [27].…”

“…The formation of this good bond if the reinforcement's surface is coarse so that for structural reinforced concrete used deform bar. The reinforcement surface roughness is expressed in the bond index's relative area value [2]- [6].…”

Experimental Study and In-depth Tensile Mechanism Analysis of Grouted Sleeve Lapping Conectors

“…Due to the use of shear keys, the ultimate bonding force is about three times that of a normal sleeve (Seyed and Ahmad, 2013). To solve the construction difficulties and lower the production cost of the sleeve connectors, Yu developed a grouted sleeve lapping connector (Yu, 2014). As shown in Figure 2, a type-I sleeve was cut from a standard pipe section, and thus does not require additional fabrication.…”

“…During construction, the steel bar from the other component is inserted in the sleeve, and the grout is injected in the sleeve through the grouting hole until the sleeve cavity is full. Test results show that the grouted sleeve lapping connector can effectively transfer the vertical stress of reinforcement bars (Yu, 2014). Bar tensile failure and bar-grout bond failure are typical failure modes of grouted sleeve lapping connectors; grout-sleeve slip and sleeve tensile failure were not shown (Yu and Xu, 2017).…”

“…Test results showed that on the premise of ensuring strength, the grouted sleeve lapping connector not only reduced the length of the connector compared with its counterpart but had better ductility. In another test study, the tensile capacity of a grouted sleeve lapping connector was found to be 2.45 times that of a grouted splice connector (Yu et al, 2019). It is more convenient to insert the reinforcement bar in a grouted sleeve lapping connector than a grouted splice connector during assembly (Yu et al, 2016).…”