Total creep of RC beam subjected to sustained loads: Experiment and numerical medeling approach

International audienc

Experimental and numerical investigation of the effect of steel fibres on the deflection behaviour of reinforced concrete beams without stirrups

International audienc

Experimental and finite element analysis of creep behaviour of steel fibre reinforced high strength concrete beams

ACLThe present study is focused on experimental investigations and numerical analyses of compressive and tensile total creep at long-term of high-strength concrete (HSC) beams. Reinforced concrete (RC) beams with and without steel fibres were investigated for their long-term creep behaviour. These beams are under sustained uniformly distributed load (SUDL) in bending containing steel fibres (SF) with two aspect ratios (55 and 80) and two steel fibre dosages (0.5% and 1%). The objective of this work is to evaluate the influence of steel fibres, their dosage and their aspect ratio on compressive and tensile total creep. Experimental results show that the long-term total creep is influenced by the volume fractions of steel fibres. Moreover, steel fibres decrease the tensile total creep more than the compressive one. A non-linear finite element method (FEM) is performed to simulate the long-term total creep strain rate included thanks to the time hardening model called generalized Garofalo creep which is based on Bailey-Norton law called power law creep. It was found a good agreement between the experimental and numerical results

experimental and nonlinear finite element analysis of shear behaviour of reinforced concrete beams

International audienceThis paper presents an experimental investigation and nonlinear finite element analysis (NLFEA), using the numerical analysis tool ANSYS © , carried out on the shear and diagonal cracking effect on the behaviour of reinforced-concrete (RC) beams made of normal strength concrete (NSC) and highstrength concrete (HSC), with and without transverse reinforcement. Beams were tested using fourpoint bending, by means of digital image correlation (DIC). In the experimental setup, the shear zone was digitised using a high-resolution camera to assess the deformation of concrete in the compression zone and to measure the diagonal crack widths. The results show that transverse reinforcement does efficiently control the diagonal crack width, increases the shear capacity of the beams, shifts the mode failure from shear to flexure, and significantly improves the ductility of beams in the ultimate state particularly when using HSC, given the better quality of the bond developed in the concrete with steel reinforcement. The values of ultimate shear strength obtained experimentally were compared to the corresponding empirical values available in the literature. Furthermore, detailed 3D finite element analysis (FEA) was used to predict the load-deflection response, the ultimate load, the cracking load, the ultimate deflection, the maximum diagonal crack widths and the cracks patterns in RC beams. The difference values between the numerical and experimental values range from −11.08 to +0.6%, from −2.02 to −0.52% and from −13.27 to −1.01% for cracking load, for ultimate load and for ultimate midspan deflection, respectively. The ratio of the predicted to experimental maximum diagonal crack width for the beams ranged between 0.95 and 1.06. Also, a good agreement between the experimental and numerical crack patterns was achieved. Consequently, the FEA model is able to predict the shear response of RC beams with a good accuracy

Creep of reinforced concrete beams under sustained loads: Experiments and numerical modeling approaches

ACTIInternational audienc

Numerical analysis of shrinkage of steel fiber reinforced high-strength concrete subjected to thermal loading

ACLIn 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

Finite element modeling of creep behavior of FRP-externally strengthened reinforced concrete beams

International audienc