Bond strength of reinforcement in splices in beams (original) (raw)
Related papers
Size effect on failure of bond splices of steel bars in concrete beams
Journal of Structural …, 1999
ABSTRACT: The results of reduced-scale failure tests of simply supported four-point-bend beams of different sizes, containing lapped bond splices of smooth (undeformed) longitudinal reinforcing bars, are reported. The tests consist of two groups, with splices ...
Techniques Used for Bond Strengthening of Sub-Standard Splices in Concrete: A Review Study
Processes
Bar splicing is considered an essential part of the construction process of reinforced concrete (RC) due to the ease of installation in construction, transportation constraints, and restricted length of reinforcing bars. Splices serve the primary role of joining reinforcement bars in standard RC elements such as columns, walls, beams, slabs, and joints. Bond behavior between the bars and the concrete is one of the fundamental qualities required for appropriate RC structure design and analysis, as it affects serviceability and ultimate limit states. The most common failure found in lap splice locations is debonding, which occurs at the splice region and insufficient lapped length is considered as the primary cause because of design or construction mistakes, design by outmoded code, and natural catastrophes. As a result, strengthening existing substandard splices in RC structures is critical. The purpose of this research is to analyze and summarize experimental strengthening solutions...
Influence of loading condition and reinforcement size on the concrete/reinforcement bond strength
Structural Engineering and Mechanics, 2005
The paper reports on a study of bond strength between reduced-water-content concrete and tensile reinforcement in spliced mode. Three different diameters (12, 16 and 22 mm) of tensile steel were spliced in the constant moment zone, where there were two bars of same size in tension. For each diameter of reinforcement, a total of nine beams (1900 × 270 × 180 mm) were tested, of which three beams were with no axial force (positive bending) and the other six beams were with axial force (combined bending). The splice length was selected so that bars would fail in bond, splitting the concrete cover in the splice region, before reaching the yield point. It was found that there was a considerable size effect in the experimental results, i.e., as the diameter of the reinforcement reduced the bond strength and the deflection recorded at the midspan increased significantly, whilst the stiffness of the beams reduced. It was also found for all reinforcement sizes that higher bond strength and stiffness were obtained for beams tested in combined bending than that of the beams tested in positive bending only.
Behavior of Fibrous Reinforced Concrete Splices
The Open Civil Engineering Journal
Background: The tangent of the relationship between bond stress and displacement (slip) is called the modulus of displacement and gives the basis for the theory. This theory is used to determine the stress distribution along the spliced reinforcement bars. Objective: This research presents a modification on the theory of the modulus of displacement to determine the stress distribution along the spliced reinforcement bond for fibrous reinforced concrete. Methods: 1- General differential equations are derived for concrete stress, stress in reinforcement bars and bond stress between reinforcement bars and surrounding concrete. 2-The general solutions of these D.E. are determined and Excel data sheets are prepared to apply these solutions and determine the concrete, steel and bond stresses. Results: Excel data sheets are prepared to determine the concrete, steel and bond stresses. The stresses are determined along the bar splice length considering the effect of steel fiber content. Conc...
Comparative study of factors influencing tension lap splices in reinforced concrete beams
2020
The practice of splicing reinforcing bars in reinforced concrete structures to manage insufficient bar length is a common approach, which is mainly due to transportation limitations on bar length. The splicing of reinforcing bars side by side offers a simple and economical solution to the problem of continuity. This paper examines the influence of different structural parameters such as concrete cover, lap splice length, shear links confinement and concrete strength on the lap splices based on an extensive experimental database of laps and anchorage. The current study shows that increasing the lap splices beyond 50∅ has no additional benefit for increasing its strength. The results also show that relative to the measured stress, specimens with larger concrete side covers shows higher splice stress compared to the samples with smaller concrete covers.
Bond Strength of Tension Lap-Splices in Full Scale Self-Compacting Concrete Beams
Turkish Journal of Engineering and Environmental Sciences, 2008
Twelve full-scale beam specimens (2000 × 300 × 200 mm) were tested in positive bending with the loading system designed to determine the effect of self-compacting concrete (SCC) and the diameter of reinforcement on bond-slip characteristics of tension lap-slices. The specimens of lap-splice series were tested with lap-spliced bars centred on the midspan in a region of constant positive bending. The splice length of the deformed bars was set at 310 mm in all beam specimens. This value was selected to develop a steel stress less than yield to ensure splitting mode failure in all beam specimens. The beams were cast with the 16 and 20 mm bars (the tension lap-splices) in the bottom position. The casting procedure was the same for all beams. Two types of concrete were used in the experimental programme, including normal concrete (NC), with a slump less than 68 mm, as the comparatively low-slump concrete, and SCC as an extremely high-workability concrete. The variables used in this study were the concrete type (SCC and NC) and reinforcing bar size (16 and 20 mm). It was found that as the diameter of the steel bar increased from 16 to 20 mm the bond strength decreased regardless of concrete type. Finally, although the compressive strength of concretes was almost the same and there were slight differences between the diameters of lap-spliced bars, the normalised bond strengths of the SCC mixes were about 4% higher than those of the NC mixes for both bar diameters, indicating that the reinforcing bar was completely covered by SCC due to its filling ability.
International Journal of Engineering Research and Technology (IJERT), 2013
https://www.ijert.org/flexural-behavior-of-rectangular-concrete-beams-with-lap-splices-between-deformed-and-smooth-reinforcement-bars https://www.ijert.org/research/flexural-behavior-of-rectangular-concrete-beams-with-lap-splices-between-deformed-and-smooth-reinforcement-bars-IJERTV2IS120547.pdf The aim of this research is to study flexural behaviour rectangular concrete beams with lap splice between deformed and smooth bars. An experimental program has been performed to investigate the research point, where sixteen rectangular concrete beams were tested in a four point bend configuration. Specimens were grouped into four groups to investigate influences of lap splice length, stirrups intensity and location, end shape, and concrete characteristic strength (N.S.C and H.S.C). It was concluded that distributing stirrups along the splice length increase failure load more than concentrating them at splice ends; end shaping of splices increases failure load; Increasing splice length compared with that required for transmission of tensile stresses through bond decreases ductility; linearity of strain distribution along reinforcement bars increase by the increase and uniformity of stirrups confinement; increasing splice length decreases the difference between strain in deformed and smooth bars.
Materials and Structures, 2002
Reports on the very brittle and splitting mode of failure of tension lap splices anchored in high strength concrete (HSC) specimens and the lower normalized bond stress [u/~) for high strength than for normal strength concrete, instigated several research projects aiming at recommending mechanisms to provide confinement and ductility for bars or splices anchored in HSC. The stateof-the-art report of ACI Committee 363, ACI 363R-84, defines high strength concrete as concrete with compressive strength above 6,000 psi (41.4 MPa).
2013
The aim of this research is to study flexural behaviour rectangular concrete beams with lap splice between deformed and smooth bars. An experimental program has been performed to investigate the research point, where sixteen rectangular concrete beams were tested in a four point bend configuration. Specimens were grouped into four groups to investigate influences of lap splice length, stirrups intensity and location, end shape, and concrete characteristic strength (N.S.C and H.S.C). It was concluded that distributing stirrups along the splice length increase failure load more than concentrating them at splice ends; end shaping of splices increases failure load; Increasing splice length compared with that required for transmission of tensile stresses through bond decreases ductility; linearity of strain distribution along reinforcement bars increase by the increase and uniformity of stirrups confinement; increasing splice length decreases the difference between strain in deformed and smooth bars.