19 research outputs found
Comportement structurel du béton à hautes performances (flexion et effort tranchant)
No full textLORIENT-BU (561212106) / SudocSudocFranceF
Behavior of reinforced concrete beams pre-cracked and repaired by composite materials under static loading
No full textThis work constitutes a contribution to the analysis of the behavior of beams repaired by composite materials. To analyze the overall behavior and failure modes of the beams, an experimental study of nine reinforced concrete beams, pre-cracked and then repaired by composite materials was conducted. Six beams were pre-cracked and repaired in the tensioned part (bending repair) and in the other two beams on the tensioned and lateral parts with strips in the shape of U (shear repair). A comparative study was made between the ultimate moments measured experimentally and those calculated by the theoretical models. Compared to the control beam, the resistance gain for the beams repaired in bending is 50% to 90%, while that of beams repaired in shear is from 120% to177 %. The beams repaired in shear exhibit a ductile rupture in bending. However, the beams repaired in bending were failed by the lift-off of composite or by failure of concrete cover layer (except for beams repaired by fiber glass). BAEL99, EC2-04 and ACI318-08 models give the best prediction of the ultimate moments with a mean value of 1.16 for the ratio of MExp./Mtheor. and a mean standard deviation of 0.33
Numerical analysis of shrinkage of steel fiber reinforced high-strength concrete subjected to thermal loading
No full textACLInternational audienceIn this study, a numerical investigation is conducted to simulate the total shrinkage strain of High-Strength Concrete (HSC) and Steel Fiber Reinforced High-Strength concrete (SFRHSC) by means of the transient thermal-stress analysis. The ANSYS finite element software has been used in order to evaluate the shrinkage by taking into account both the thermal and mechanical properties of the concrete. These properties are calculated using the maturity concept and the two-phase serial model. The experimental work was carried out to assess the influence of the external temperatures, steel fibers (SF) and their volume fraction on the total shrinkage strain of the SFRHSC which has been exposed to isothermal temperature of 20, 35 and 50 °C. Two dosages of 0.5% and 1% for the SF with aspect ratio of 55 have been considered. The main results obtained from the FE analysis show a good agreement with the founded experimental results under different thermal conditions. According to the obtained numerical results, an increase of the dosage of fibers will reduce the total shrinkage strain. Additionally, the curing temperature raises significantly the evolution of the total shrinkage strain
Reinforcement of concrete by composite materials
No full textThis work was devoted to the material-scale study of the mechanical behavior of confined concrete by composite materials based on carbon fiber and glass under compression and bending loading. In this context, an experimental work on cylindrical and prismatic concrete specimens has been carried out. The obtained results permitted the identification of the mechanical behavior, strength, deformability and failure modes. The outcome of the present research indicates an increase in the bearing capacity and deformability in compression and in tension. The reinforcement by means of composite materials appears as a pertinent solution and therefore, makes it possible to obtain clear indication on the type of confinement to be considered according to the intended purpose.</jats:p
Flexural behavior of reinforced concrete beams: Comparative analysis between high-performance concrete and ordinary concrete
No full textThis paper presents an experimental study on the flexural strength of reinforced concrete beams made with high performance concrete (HPC) and ordinary concrete (OC). We are carried an experimental campaign aimed comes in three points: 1- the study of the law of behavior of the two materials (OC and HPC), 2- the influence of the compressive strength of concrete and the rate of longitudinal reinforcement on the loaddeflection behavior and ductility index, 3- comparative analysis (ACI318, Eurocode 2 and BS8110 ) against the crack opening. Test results showed that the capacity of the beams in HPC is higher (6% to 20 %) than the beams in OC. The use of HPC is more efficient than the OC to delay the first cracking. The average value of the ductility index for the beams in HPC is 1.30 times those beams in OC. The formula for calculating the crack opening derived of the Eurocode 2 gives the best prediction the crack width of beams (for both types of concrete)
Finite element modeling of creep behavior of FRP-externally strengthened reinforced concrete beams
No full textInternational audienc
Reinforcement of concrete by composite materials
No full textThis work was devoted to the material-scale study of the mechanical behavior of confined concrete by composite materials based on carbon fiber and glass under compression and bending loading. In this context, an experimental work on cylindrical and prismatic concrete specimens has been carried out. The obtained results permitted the identification of the mechanical behavior, strength, deformability and failure modes. The outcome of the present research indicates an increase in the bearing capacity and deformability in compression and in tension. The reinforcement by means of composite materials appears as a pertinent solution and therefore, makes it possible to obtain clear indication on the type of confinement to be considered according to the intended purpose
Influence of yield stress and compressive strength on direct shear behaviour of steel fibre-reinforced concrete
No full textFlexural behavior of reinforced concrete beams: Comparative analysis between high-performance concrete and ordinary concrete
No full textThis paper presents an experimental study on the flexural strength of reinforced concrete beams made with high performance concrete (HPC) and ordinary concrete (OC). We are carried an experimental campaign aimed comes in three points: 1- the study of the law of behavior of the two materials (OC and HPC), 2- the influence of the compressive strength of concrete and the rate of longitudinal reinforcement on the loaddeflection behavior and ductility index, 3- comparative analysis (ACI318, Eurocode 2 and BS8110 ) against the crack opening. Test results showed that the capacity of the beams in HPC is higher (6% to 20 %) than the beams in OC. The use of HPC is more efficient than the OC to delay the first cracking. The average value of the ductility index for the beams in HPC is 1.30 times those beams in OC. The formula for calculating the crack opening derived of the Eurocode 2 gives the best prediction the crack width of beams (for both types of concrete)
Experimental study of deflection of steel fibre reinforced concrete beams: comparison of different design codes
No full textInternational audienc
