Influence Of Transverse Reinforcement Research Articles

Prediction of Flexural Strength of RC Circular Columns Considering Lateral Confinement Effects of FRCM and Transverse Steel Reinforcement

There has recently been growing interest in making a sustainable and durable fiber reinforced cementitious matrix (FRCM) to improve the seismic performance of RC column members. However, most studies evaluating the lateral confinement effect on FRCM jacketing concrete have excluded the confinement effect of transverse steel reinforcement and focused solely on mechanical properties. This paper, based on existing studies, proposes a peak axial stress formula that considers the lateral confinement effects of FRCM composite and transverse steel reinforcement. Additionally, the study assesses the structural performance of FRCM composites with flexural strengthening in actual size RC circular columns and predicts the maximum flexural strength by applying the proposed formula. The proposed peak axial stress formula, considering the influence of transverse reinforcement, was compared with the experimental value (databases) and the predicted value, and the suitability was confirmed with a standard deviation of 27.6% and a coefficient of variation of 0.856. In addition, the maximum flexural strength of actual size RC circular columns predicted by applying this formula ranged from 0.97 to 1.02, which effectively predicted the experimental values.

EXPERIMENTAL STUDIES ON THE INFLUENCE OF TRANSVERSE REINFORCEMENT FOR STRENGTH OF COMPRESSED REINFORCED CONCRETE ELEMENTS

The infl uence of transverse reinforcement, including indirect reinforcement, on the strength of compressed reinforced concrete elements is analyzed. This question arose in connection with the possibility of increasing the strength of short reinforced concrete elements loaded with a longitudinal force with small eccentricities within the section of the element. For such elements, the cage eff ect may appear, associated with the coeffi cient of transverse deformations, the magnitude of which is a direct factor in the destruction of the concrete sample, and the limitation of these directly aff ects the bearing capacity of the sample in the direction of increase. The infl uence of transverse reinforcement in the form of stirrups located with diff erent spacing, as well as indirect reinforcement in the form of meshes with a classical rectangular cell and meshes of the “zigzag” type is considered.

The influence of transverse reinforcement and yielding of flexural reinforcement on the shear-transfer actions of RC members

The assessment of the shear strength of reinforced concrete beams with and without shear reinforcement is investigated in this paper on the basis of the contribution of the various potential shear-transfer actions. To that aim, a comprehensive experimental programme is presented, aimed at representing realistic conditions in reinforced concrete members. The programme comprised 15 cantilevers and 15 continuous beams with and without stirrups. In addition, some of the tests were designed to fail in shear after yielding of the flexural reinforcement, allowing to investigate on the structural implications of this phenomenon. The tests were instrumented by means of surface measurements using Digital Image Correlation (DIC), tracking in a detailed manner the development and kinematics of the critical shear crack leading to failure. Based on these measurements, and by accounting for suitable constitutive models, the contribution of the shear-transfer actions is estimated at different levels of load.The comparison of the experimental results with the calculated shear strength (sum of the contribution of the various shear-transfer actions at failure) shows consistent agreement for the various cases investigated. On this basis, several conclusions about the dominant shear-transfer actions at shear failure are presented, particularly on the role of the shear reinforcement and on the implications of the flexural reinforcement yielding on the overall response.

Finite-Element Study on the Behavior of Exterior Reinforced Concrete Beam-to-Column Connections with Transverse Reinforcement in the Joint Panel

AbstractThis paper deals with the influence of transverse reinforcement (TR) in the joint panel on the behavior of RC beam-to-column moment-resisting connections. For this purpose, a numerical stud...

An evaluation of EC2 rules for design of compression lap joints

This paper presents an evaluation of EC2 rules for design of compression lapped joints based around a database of approximately 150 individual test results reported in the literature. A comparison is provided between tension and compression laps, and a review of semi-empirical and empirical expressions reported in the literature is presented. Compared to laps of bars in tension, the influence of minimum concrete cover on compression lap strength is low or negligible, but the influence of transverse reinforcement is stronger. The performance criteria for lapped joints are discussed, and a difference noted between compression and tension laps.The evaluation has been carried out by first determining the lap length required by EC2 to develop the design strength of a bar, and the strength of that lap then estimated using three different semi-empirical expressions each derived from part of the database. The outcome shows that EC2 procedures provide a greater margin of safety for compression laps than for tension laps. The margin of safety against failure of compression laps designed in accordance with EC2 is found to be broadly consistent with expectations for a concrete cover equal to one bar diameter, but reduces at larger cover/bar diameter ratios. Consequently it is recommended that for compression laps coefficient α2 be independent of cover ratio and set to 1.0.

REGULARITIES IN PROPAGATION OF OPENED CORROSION‐INDUCED CRACKS IN CONCRETE

Long and short‐term (accelerated with simulation of pressure developed by compressed rust) experimental investigations were accomplished. It was investigated in long‐term tests the relationship between the width of the longitudinal cracks on the concrete surface and close to the reinforcement, and relation between these widths and corrosion‐induced damages in the reinforcement; parameters of these relationships were established. In short‐time investigations it was tried to clarify the influence of transverse reinforcement and opened normal cracks on the nature of longitudinal cracks propagation. It has been determined that the character and the rate of propagation of the longitudinal cracks depend on distribution of transverse reinforcement and normal cracks along a member.

Influence of transverse reinforcement on elastic shear stiffness of cracked concrete elements

Various truss models for calculating the cracked elastic shear stiffness due to transverse reinforcement are investigated to determine the threshold of the geometrical configuration of concrete beams and columns, in which the more convenient continuum truss model can substitute for the discrete truss model without losing accuracy. For this purpose, a comparison is made between continuum and discrete truss models, between constant and variable angle truss models, and between rectangular hoops and circular hoops and spirals. For the continuum truss model to substitute for the discrete truss model, the center-to-center space between transverse reinforcements should be limited to s ≤ d c / 5 for rectangular hoops and s ≤ d c / 3 for circular hoops and spirals. The minimization of energy due to combined flexure and shear mechanisms leads to the construction of formulae for the inclination of diagonal cracks. This angle, θ , is a key parameter for a shear strength and stiffness analysis. The validity of the crack angle formulae is verified through a comparison of the theoretical crack angles with those measured from experimental results reported in a number of earlier studies.

Influence of transverse reinforcement on bond strength of tensile splices

The influence of transverse reinforcement on bond strength of tensile splices is investigated. An equation to calculate the bond strength of splices confined and not confined by transverse reinforcement is presented. The equation which covers all grades of concrete shows good correlation with test results. For instance for 138 normal strength concrete test results reported in the literature the mean value of test/calculated bond strength is 1.00 with a standard deviation of 0.10. These values indicate a significant improvement in the prediction of the bond strength when compared to the values obtained from other models.

The fracture toughness of conventional materials and composite systems containing non-fracturing reinforcing elements

A preliminary study has been made of the fracture surface energies and modes of failure of unidirectionally reinforced fibrous composites containing bicomponent (duplex) reinforcing elements with non-fracturing cores. Local high stress concentrations have been produced by the use of severely notched specimens of the Tattersall and Tappin type which have been tested in three-point bending. Comparisons have been made with conventional materials tested under similar conditions. It has been shown that the duplex fibre-reinforced specimens are able to support a substantially constant load up to deformations at which conventional materials have either failed completely or are able to support only relatively negligible bending loads. The effective fracture surface energies of experimental duplex fibre systems subjected to this degree of deformation are of the same order of magnitude, on a weight for weight basis, as those of the toughest available metal alloys. It is observed that when the permanently deformed duplex fibre systems are subjected to further deformations of a cyclic nature within the relevant elastic range of the material, relatively large amounts of energy are absorbed by frictional losses during decoupling and recoupling of the core-sheath interface. Possible reasons for this are discussed. The influence of transverse reinforcement on the generation and development of secondary matrix cracks has also been investigated.

Influence of Transverse Reinforcement on Shear and Bond Strength

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