Effect of flexural crack on plain concrete beam failure mechanism A numerical simulation (original) (raw)
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Effect of flexural crack on plain concrete beam failure mechanism A numerical .PDF
The flexural failure of plain concrete beam occurs along with development of flexural crack on beam. In this paper by using ABAQUS, mechanism failure of plain concrete beam under three steps have been simulated. The cracking moment has been analytically calculated and applied on the both sides of the fixed beam, and flexural crack has been simulated on beam. Displacement, von Mises, load reaction, displacementcrack length, von Mises-crack length and von Mises-displacement of beams have been graphical depicted. Results indicated that, the flexural crack governs beam mechanism failure and its effects on beam resistance failure. It has been found that the flexural crack in initial stage it developed slowly and changes to be fast at the final stage of collapsing beam due to reduction of the flexural resistance of beam. Increasing mechanical properties of concrete, collapse displacement is reduced.
A Review of Analysis of Concrete Beam by Fracture Mechanics Approach
Petersson (1981) had conducted a three-point bend test on notched concrete beam in order to determine the fracture behaviour of the concrete in tension. In this paper, in order to understand actual behaviour of the concrete beam, relevant theory is studied from literature. A finite element analysis is done subsequently to simulate behaviour of the beam. For this, a two dimensional prototype model of the experimentally tested beam is modelled and analysed in a finite element based software. The load-displacement response of the beam is obtained and compared with the experimental results. In order to carry out mesh refinement study the prototype model is discretized into three different mesh sizes as a coarse, medium and a fine mesh. Further, the influence of shape of stress-displacement relations on the load-displacement response is also discussed. The absolute stress-displacement curve for concrete given by Petersson is approximated by 1-segment, 2-segment and a 4-segment curve. Three different approximations for the shape of stress-displacement relations are used to evaluate the sensitivity of the degree of the curve.
International Journal of Civil Engineering and Technology (IJCIET) Volume 13, Issue 9, September 2022, pp. 1-13, Article ID: IJCIET_13_09_001, 2022
The failure behavior of reinforced concrete beam structural elements was modeled using computer software, ANSYS, to create the study presented in this paper. This study's goal was to ascertain how lower concrete and steel quality affected the way single reinforced concrete beam structural parts failed under tensile failure conditions. In this investigation, eight specimens of a straightforward 200x400x3000 mm with 2D16 single-reinforced beam have been modeled. A concentrated load will be applied to the beam in the middle of the beam span until it is collapsed. According to the study's findings, the quality of steel does not significantly change when the ultimate load is a flexural crack, and neither does the quality of concrete, which results in a smaller flexural capacity but a larger deflection. The crack pattern is also not significantly affected by this change. According to SNI 2847:2019, the flexural capacity of the ANSYS software analysis is comparable to the simplified calculation analysis, with a discrepancy of adequately reasonable. It is advisable for the low concrete steam rength beam with a low grade of reinforcement, whilst the higher concrete strength by using high-grade rebar.
International Journal of Engineering Research and Technology (IJERT), 2014
https://www.ijert.org/a-study-on-load-deflection-behaviour-of-cracked-concrete-beam-using-fem-fracture-mechanics-approach https://www.ijert.org/research/a-study-on-load-deflection-behaviour-of-cracked-concrete-beam-using-fem-fracture-mechanics-approach-IJERTV1IS6421.pdf This paper presents a series of load-deflection tests on concrete beams in order to develop a load-deflection model for concrete beam with an edge crack , under vertical loading condition. The proposed model is based on analysis of a series of Finite element analysis generated models and an edge crack of 75 mm is modeled based on the principles of the fracture mechanics.A total of 6 beams of length 3000mm,3100mm and 3200mm and 250x125m cross-sectional area ,with and without edge cracks were tested in this investigation .The beams were modeled and tested as four point bending test under a gradual loading of 70000N.The load-deflection behaviour of cracked beams and normal beams were predicted using finite element analysis(ANSYS).For normal beams comparision has been made between theoretical values with the Ansys predicted value and found good correlation .Throughout the analysis the pre-peak responses of the load-deflection is recoreded.The results show that the presence of a crack reduces the strength of the member and shifts the load-deflection curve downwards when compared with the normal beams.finally the percentage increase in deflection of the beam with and without crack with respect to the length is plotted .This shows the effect of the length and crack on load-deflection behavior.it is found that the proportionate percentage increase in central deflection is reduced with an increase in length but not in magnitude.
4th International Conference on Advances in Civil Engineering, 2018
The use of high strength concrete has become popular in construction work because of its improved strength and durability. High-strength concrete can be used as a substituting material over conventional concrete for structural members. This study describes the flexural behaviour of high strength reinforced concrete beam. The variation of flexural ductility with concrete compressive strength is quite complicated and thus sincerely reviewed in this paper. An experimental and numerical investigation of high strength reinforced concrete beam has been conducted in the present study. Four simply supported beams, having compressive strength of 27.50 MPa, 43.85 MPa, 54.05 MPa and 62.01 MPa, reinforced in top and bottom edges of the beam have been investigated in this study. The beams were tested under two-point loading to reveal their flexural behaviour. Load-deflection diagram and ductility index are the primary parameters that were considered in this study. The ultimate loads that obtained from the experimental results were found to be in good agreement with the numerical results. In addition, this study also compared the theoretical and experimental deflection at the mid-point of the beam. The cracking behaviour of all the beams and the crack width is also reviewed in this paper.
This paper discusses about 3D ANSYS FE modeling of the failure behavior of structural reinforced concrete beam element. The capacity of the bending moment, deformation, stress, strain and fracture patterns is determined that occurs on a single reinforced concrete beams with different types of collapsed mechanisms. The RC beam specimens of normal strength is modeled by rectangular section with tensile steel reinforcement ratios to represent the tensile, balanced, and compressive collapsed mechanism. The beams is subjected to concentrated load at middle span and collapsed behavior observed from load of the first crack up to fully collapse. The results show that the reinforced concrete beams can be analyzed using ANSYS software with modified model. The behavior of reinforced concrete beams can be determined by the analysis of calculation and FEM that beams with tensile collapsed condition has a lower flexural capacity and collapse behavior is more ductile than that of the beam with the compressive collapse and balanced condition. According to SNI 03-2847 manual calculation analysis is more suitable to represent the RC beam behavior of collapsed condition.
Process of cracking in reinforced concrete beams (simulation and experiment)
Frattura ed Integrità Strutturale, 2016
The paper presents the results of experimental and theoretical investigations of the mechanisms of crack formation in reinforced concrete beams subjected to quasi-static bending. The boundary-value problem has been formulated in the framework of brittle fracture mechanics and solved using the finite-element method. Numerical simulation of the vibrations of an uncracked beam and a beam with cracks of different size serves to determine the pattern of changes in the spectrum of eigenfrequencies observed during crack evolution. A series of sequential quasi-static 4-point bend tests leading to the formation of cracks in a reinforced concrete beam were performed. At each loading step, the beam was subjected to an impulse load to induce vibrations. Two stages of cracking were detected. During the first stage the nonconservative process of deformation begins to develope, but has not visible signs. The second stage is an active cracking, which is marked by a sharp change in eingenfrequencies. The boundary of a transition from one stage to another is well registered. The vibration behavior was examined for the ordinary concrete beams and the beams strengthened with a carbon-fiber polymer. The obtained results show that the vibrodiagnostic approach is an effective tool for monitoring crack formation and assessing the quality of measures aimed at strengthening concrete structures.
Fracture mechanics approach for flexural strengthening of reinforced concrete beams
Engineering Structures, 2009
This paper reports on the experimental testing of 9 notched reinforced concrete specimens under four point bending. The beams comprise three beam sizes and three tension reinforcing steel ratios. All beams have constant span/depth ratio of 4, initial notch/depth ratio of 0.3. Two strengthening fiber laminates were used: Glass fiber for the two lower tension reinforcing steel ratios and Carbon fiber for the higher tension reinforcing steel ratio. The strengthening laminates were designed to enhance beam moment capacity by 15% to 150% depending on the beam size and reinforcement ratio. To simulate real life strengthening situations, beams were first loaded until the notch propagated to 0.5 the beam depth. The strengthening fiber laminate was then introduced to the tension side of the beam while the load was kept applied to the other side of the beam. The fracture moment for a given crack depth was calculated through an analytical algorithm which employs Linear Elastic Fracture Mechanics. The approach takes into consideration the previous loading history of the beam prior to introducing the strengthening laminate. Test measurements of crack extension and applied load were used to compare the fracture moment recorded experimentally to that one calculated analytically. The application of the solution algorithm to different specimen sizes-cross-section dimensions, reinforcement ratio, and strengthening fiber laminate-showed that the solution algorithm is able to effectively predict the behavior of larger beam size and/or reinforcement better than that of smaller beam size and/or reinforcement. A sensitivity analysis was conducted to explore this point.
Finite Element Analysis of Concrete Beam under Flexural Stresses Using Meso-Scale Model
Civil Engineering Journal
Two dimensional meso-scale concrete modeling was used in finite element analysis of plain concrete beam subjected to bending. The plane stress 4-noded quadrilateral elements were utilized to model coarse aggregate, cement mortar. The effect of aggregate fraction distribution, and pores percent of the total area – resulting from air voids entrapped in concrete during placement on the behavior of plain concrete beam in flexural was detected. Aggregate size fractions were randomly distributed across the profile area of the beam. Extended Finite Element Method (XFEM) was employed to treat the discontinuities problems result from double phases of concrete and cracking that faced during the finite element analysis of concrete beam. Cracking was initiated at a small notch located at the middle of the bottom face of the concrete beam. The response of plain concrete beam subjected to pure bending via two point load application was detected using (XFEM) analysis of meso-scale concrete model. ...
A MATERIAL MODEL FOR FLEXURAL CRACK SIMULATION IN REINFORCED CONCRETE ELEMENTS USING ABAQUS
This paper presents a material model to simulate load induced cracking in Reinforced Concrete (RC) elements in ABAQUS finite element package. Two numerical material models are used and combined to simulate complete stress-strain behaviour of concrete under compression and tension including damage properties. Both numerical techniques used in the present material model are capable of developing the stress-strain curves including strain softening regimes only using ultimate compressive strength of concrete, which is easily and practically obtainable for many of the existing RC structures or those to be built. Therefore, the method proposed in this paper is valuable in assessing existing RC structures in the absence of more detailed test results. The numerical models are slightly modified from the original versions to be comparable with the damaged plasticity model used in ABAQUS. The model is validated using different experiment results for RC beam elements presented in the literature. The results indicate a good agreement with load vs. displacement curve and observed crack patterns.