Papers by Keyword: Concrete Beam

Abstract: Shear behavior of reinforced concrete beams using steel lathe scrap waste and end hooked steel fibers as fully or partially web shear reinforcement replacement was studied. Steel lathe scrap waste is generated from industrial steel waste and can be used as recycled fibers offering additional advantages towards environmental pollution reduction. To investigate their effect of reinforced concrete beam under shear behavior, ten reinforced concrete beam specimens with 1200 mm long, 200 mm wide, and 300 mm high were tested under quasi-static loading (two-point loading). The studied parameters in this investigation were types of fibers such as steel lathe waste fiber and traditional hooked steel fiber ratio and the web shear reinforcement ratio are zero% and 50%. Results observed were initial and post-cracking stiffness, maximum capacity load, vertical displacements, modes of failures, and the ductility of the specimens. It was concluded that using of steel lathe scrap waste and hooked steel fibers in concrete are advantageous, they changed the mode of failure of the beam from a brittle to a ductile mode of failure due to the ductility of steel used, whether traditional steel fiber or steel lathe waste fiber. The optimum ratio of the steel lathe scrap waste was found equal 0.5% while the optimum ratio of traditional hooked steel fiber is 1% as fractional volume.

Abstract: This study discusses the results of experiments on flexural strength of the concrete beams using bambo strip notch as reinforcement, with variations in the distance between the notch at 40 mm and 50 mm. The flexural parameters assessed were the flexural moments and load-deflection behaviour. The number of concrete beams specimen was 9 units. One sets for 3 beams containing round steel 8 mm as reinforcement and two sets of 6 beams containing bamboo as reinforcement were tested for flexural strength under third point loading. All beam specimens size is 110x150x1700 mm. The data recorded while tested the flexure were a failure load, deflection and failure models. The failure loads of beams increased with increase in the number of notches bamboo strip in the tensile zone. The ultimate moment experimental and theoretical of bamboo strip notched concrete beams increased, with increase the number of notches bamboo strip in the tensile zone. Thus it can be concluded that inclusion of bamboo strip notches as reinforcement in tension zone improved the flexural capacity of concrete beams.

Abstract: Basalt Fibre Reinforced Polymer (BFRP) is a new material in civil engineering and has shown to be a promising material for infrastructure strengthening. In comparison to carbon fiber, glass fiber and other composites, it has some advantages such as high-temperature resistance and low cost. At the Structural and Composite Laboratory at Reykjavik University (SEL) several research projects involving strengthening concrete beams and columns by using FRP materials have been on-going in recent years. These tests have shown improvements in strength and durability compared to unstrengthened concrete members. The benefit of using basalt fiber or other FRP material is that they are non-corrosive, which is a good choice for reinforcing concrete structure exposed to de-icing salts, for examples in bridge decks and parking garage elements. Also for concrete exposed to marine environment, such as seawalls, water breaks and buildings or other structures located near a waterfront. Two research projects are presented in this paper; a test of prestressed concrete with internal basalt rods instead of steel and a test of columns strengthened by wrapping fibre-reinforced composite sheets around the columns to increase their strength and ductility. These experimental tests show increasing strength and ductile for both the beams and the columns.

Abstract: This paper deals with the application of Glass Fiber Reinforce Polymer (GFRP) to shear reinforcement for deep beam. Instead of steel stirrup, GFRP shear reinforcement was fabricated in the form of plate with openings and embedded in concrete. An experimental study was performed to evaluate the shear behavior of eight shear reinforced concrete deep beam. Shear test was conducted in which the shear span-to-depth ratio were 1.1, 1.3 and 1.6. Also, shear reinforcement area, and effective depth were considered as variables. Crack patterns, failure modes, and load-displacement were compared in order to evaluate shear strength of the specimens. The effects of these variables on the shear strength of the deep beam were examined. The test results in terms of the shear span-to-depth ratio showed that shear strength increased when the ratio decreased. Also, it showed that shear strength increased as the reinforcement area and the effective depth increased.

Abstract: The flexural capacity formula of reinforced concrete structure strengthened with FRP in Code for Design of strengthening concrete structure(GB 50367—2013) was introduced, and the rationality of the formula was analyzed. The results showed that the concrete compression height is independent of the tension strength of Fiber Reinforced Plastic (FRP), and the concrete compression height decreases with the increase of the tension strain of FRP, which is contrary to fact. The flexural capacity formula of reinforced concrete structure strengthened with FRP in Code for Design of strengthening concrete structure (GB 50367—2013) is worth discussing.

Abstract: To investigate the influence of shear span ratio for the shear behavior of reinforced concrete beam with HRBF500 high strength rebars as stirrups, an experiment was carried out, which included 8 simply supported beams with HRBF500 rebars as stirrups. Under concentrated loads, the crack, deflection, strain of rebars, bearing capacity and failure mode are observed under different shear span ratios. Some comparisons are made between test results and calculated outcome. It shows that the shear span ratio has very important influent on the shear behavior of reinforced concrete beam with HRBF500 high strength bars as stirrups. Formula in code for design of concrete structures can be used to calculate its shear capacity with enough safety.

Abstract: The concrete column with a longitudinal hole has been loaded by a system of forces. Within the beam around the hole, the values of the tensile stresses exceed the limit. Implementing the stress of the opposite direction, they could be eliminated. This stress is induced by four bars prestressed for 100 kN. A detailed FEM model is presented in the paper.

Abstract: This paper investigates the flexural performance of plain concrete beams bonded with wire mesh-epoxy composite. A total of four beam specimens were prepared and tested. Three specimens were bonded with same amount of wire mesh-epoxy composite with varying composite width and one plain concrete specimen was used as a control. The effect of wire mesh-epoxy composite on enhancing the flexural behaviour of concrete beams as well as the effect of different configurations of composite was studied. Test results showedthat the wire mesh-epoxy composite increased the flexural strength of concrete beams. The increase in energy absorption of bonded beams was remarkable. In addition, specimen with large composite width showed better behaviour with respect to energy absorption capability.

Abstract: A test of bending resistance and reinforcement is carried out on RC beams by applying sheet of glass fiber reinforced plastics (GFRP). A study and analysis is given to the traits of bending and rupture of RC beams reinforced by applying GFRP and to the effect of GFRP on ultimate bearing capacity and stiffness of the beams. The strengthening effect is investigated to give guidance in practice work.

Abstract: In the sphere of the consolidating technique of the engineering structure the new and developing theory of the steel adhered reinforcement has gradually applied to the practical engineering. Reinforcement steel structural adhesive is a method using steel plate pasting on the component surface to improve bearing capacity of the structure, which is widely used in reinforced concrete bending, eccentric compression and tension reinforcement. In this paper, based on continuum damage theory and statistical strength theory, Starting from each phase of the concrete, medium micro softening plasticity and strain of non-uniform, Numerical simulation of steel bonded reinforcement bending failure of concrete beam was carried out and Analysis of the crack propagation and failure form were put forward. Based on FEM analysis, the size of material and binder were selected reasonably, ensuring the safety and durability of concrete beams, provide technical support for the practical engineering as well.