Analysis Of RC Beams Research Articles

Finite Element Simulation and Analysis of RC Beams with Modified Stirrups

This paper uses the finite element simulation to examine the effects of modified stirrups on RC beams. There are seventeen (17) FE models, including various stirrup configurations such as traditional, spiral, and truss systems, as well as advanced modifications, were thoroughly analyzed using Abaqus software to evaluate parameters such as loaddeflection relationship, ductility, strength, failure modes, and crack patterns. Among these models, the BT-X design with a 125 mm spacing inclination of 72.10° demonstrated a remarkable load capacity of 110.856 kN, outperforming BN by 7.637%. Notably, throughout the simulation, the BT-R and BT-X designs were shown to be effective at increasing load-carrying capacity. Stirrup spacing and inclination angles are essential influences on RC beam performance. Specifically, the BT-X 125 design significantly improved flexural capacity and ductility. Furthermore, a uniform failure mode was identified across all models, highlighting the positive effect of modified stirrups on RC beam behavior. These findings highlight the importance of changing the stirrup design and selecting spacing and inclinations to improve RC beam performance.

Non-Iterative Model for Analysis of RC Beams Strengthened with Textile Reinforced Concrete

ABSTRACT Textile reinforced concrete (TRC) is a promising material for strengthening of reinforced concrete beams due to the possibility of customizing both textile and matrix to achieve the targeted strain hardening under tensile load. Considering the complexity involved in material behaviour of TRC, the independent material characteristics majorly influence the response of the strengthened system. Presently, simple mathematical prediction models for TRC strengthened systems are few. The objective of this paper is to propose a simplified non-iterative approach to predict the behavior of RC beams strengthened with TRC. The material response calibrated based on experimental data of RC and TRC is used to develop the model using two material properties and ten non-dimensional parameters. The material parameters are described using Young´s modulus and first-crack strain of TRC in addition to various non-dimensional parameters that define strain hardening of TRC, tensile strength of steel, compressive strength of concrete and ultimate strain levels. The strain hardening of TRC is accurately incorporated, and the appropriate failure criteria for the strengthened system are idealized. Curvature at a particular section is calculated by using strain values. Parametric studies revealed that the material nonlinearity is adequately addressed and salient stages of the strengthened system predicted till failure.

Finite Element Analysis of RC Beams by the Discrete Model and CBIS Model Using LS-DYNA

There are several techniques to simulate rebar reinforced concrete, such as smeared model, discrete model, embedded model, CLIS (constrained Lagrange in solid) model, and CBIS (constrained beam in solid) model. In this study, however, the interaction between the concrete elements and the reinforcement beam elements is only simulated by the discrete model and CBIS (constrained beam in solid) model. The efficiency and accuracy comparisons are investigated with reference to the analysis results by both models provided by LS-DYNA explicit finite element software. The geometric models are created using LS-PrePost, general purpose preprocessing software for meshing. The meshed models are imported to LS-DYNA where the input files are then analyzed. Winfrith and CSCM concrete material options are employed to describe the concrete damage behavior. The reinforcement material model is capable of isotropic and kinematic hardening plasticity. The load versus midspan deflection curves of the finite element models correlate with those of the experiment. Under the conditions of the same level of accuracy, the CBIS model is evaluated to have the following advantages over the discrete model. First, it has the advantage of reducing the time required for FE modeling; second, saving computer CPU time due to a reduction in total number of nodes; and third, securing a good aspect ratio of concrete elements.

Tensile stress-strain relaxation as a failure precursor for FRP-strengthened RC beams

Abstract The paper presents findings from an experimental investigation and finite element (FE) analysis of RC beams strengthened in flexure and shear with externally bonded carbon FRP composites. The work initially focuses on the brittle plate-end concrete cover failures of RC beams strengthened in flexure only. The strain measurements reveal that the ’plate-end debonding’ is preceded by tensile relaxation in the anchorage zone of the FRP plate as a result of tension softening within the concrete cover layer. Experimental work then dealt with the role of the side-bonded ’U’-shaped FRP strips in preventing the plate-end concrete cover failure and in increasing shear capacity of flexurally strengthened concrete beams. For the two strengthening configurations, with and without FRP strips, FE models developed with ADINA and ABAQUS were used to predict brittle failure through concrete. The non-linear FE analysis based on the smeared-crack constitutive model for concrete in tension produced the load-history of principal tensile stresses in concrete at the plate-end. This load-history was then used to define a design criterion for predicting the safe load levels against the plate-end concrete failure for FRP-plated RC beams.

The Ultimate Bearing Capacity Analysis of RC Beams Strengthened by Externally Bonded and Anchored I-Section Steel

At first, mechanical behaviour and failure pattern are analyzed in the condition of full bond (with no relative deformation) with I-section and RC beam, and influence of unloading degree in this text, the theory formula of bearing capacity correspondence to failure pattern is erected, the appropriate simple calculate in engineering employ are submitted. In the condition of large the initial reinforcement ratio and the advice is given that strengthening by externally bonded and anchored I-section steel is avoided. Besides, in the condition of considering of bold-slid, the formula of interface stress is erected. Base on the relative slipping effect, the theory formula of additional moment that is derivable from slid action, and the influence of the thickness of glue, unloading degree the ratio of I-section steel to additional moment is discussed.

Load-Deflection Analysis of RC Beams Strengthened with External CFRP Sheets

Abstract. This paper is dedicated to the load-deflection analysis of RC beams strengthened with external CFRP sheets. A theoretical nonlinear model, based on slip and bond stresses, is described and adopted for the deformability predicition of beams. The model allows considering the bond-slip relationships both between concrete and steel bar and between concrete and CFRP. Comparisons between the simulated midspan deflection and that of experiment indicate that the proposed nonlinear model is able to predict the deformability behavior of RC beams strengthened with external CFRP sheets.

Simulation Calculation Analysis of RC Beam Strengthened with Carbon-Fiber by Reverse-Arch Method

Using utilities equipment to make the reinforced concrete girder to generate a kind of reverse-arch radian, then paste CFRP on the under-part of the girder, after the CFRP was maintained, unload, at this time, the CFRP is working together with the primary reinforced concrete girder. Using analysis software ANSYS to simulate this process, comparing with the RC beam strengthened with carbon-fiber directed, a conclusion was got that is the deflection of a RC beam strengthened with carbon-fiber by reverse-arch method is much smaller and the CFRP to bear much loads than the ordinary method. The conclusion can be a reference to the similar projects.

Numerical Analysis of RC Beams Strengthened with Pre-Stressed CFRP Sheets

Through the finite element analysis software, fourteen strengthened beams are calculated in the condition of considering bonding-slip or not respectively. Comparing simulation results with test and theoretical calculation, We can draw the following conclusions: Testing reinforced concrete beams when there is no debonding, ANSYS simulation, theoretical calculations and experimental results agree well. Testing reinforced concrete beams when there is debonding. By considering the bond-slip calculation model calculation accuracy is higher. .Numerical results show that, prestressed CFRP with relative of prestressed girder of carbon fibre reinforced beam can significantly improve the cracking beam loading, and effectively improve the yield loads, but the ultimate load.

Experimental Study on Short-Term Rigidity for Reinforced Concrete Beams Strengthened with CFRP Board

The experimental study and finite element analysis of RC beams strengthened with CFRP board are introduced in this essay. Test research of six beams stuck with CFRP board on their tension faces has been carried out on rigidity by contrasting with three non­strengthened beams. Three specimens are primary loading beams and the others are secondary loading beams, the calculating formula for the short-term rigidity on the section of concrete beams strengthened with CFRP board has been established. Calculation is carried out on short-term deflection of RC beams strengthened with CFRP board subjected to primary load and secondary load. The results indicate that the RC structure can be strengthened effectively by sticking with CFRP board, so that the expansion of crack and rigidity of beam can be controlled especially, and the experimental results compared with those predicted by the formula in resemblance.

Ultimate Load Analysis of RC Beam under Combined Action of Axial, Bending and Shear Loading

Based on Timoshenko beam theory, a section model for the ultimate load analysis of RC beam under combined action of axial force, bending and shear force is presented in this paper. Especially, the transverse deformation is considered with the appearance of diagonal cracks. The validity of the model is established by comparing its results with several tests. These simulations include ultimate bending moments of pure bending tests and ultimate shear loads with different shear-span ratios. The analytical results show excellent agreement with experimental data.

Analysis of RC beams subjected to shock loading using a modified fibre element formulation

In this paper an improved one-dimensional frame element for modelling of reinforced concrete beams and columns subjected to impact is presented. The model is developed in the framework of a flexibility fibre element formulation that ignores the shear effect at material level. However, a simple shear cap is introduced at section level to take account of possible shear failure. The effect of strain rate at the fibre level is taken into account by using the dynamic increase factor (DIF) concept for steel and concrete. The capability of the formulation for estimating the element response history is demonstrated by some numerical examples and it is shown that the developed 1D element has the potential to be used for dynamic analysis of large framed structures subjected to impact of air blast and rigid objects.

Nonlinear Analysis of RC Beams Damaged by Corrosion of Reinforcement using RBSM <i>Michihiro TOMIDA, Yasuo KAJIKAWA and Kazutaka KUNO</i>

Nonlinear Analysis of RC Beams Damaged by Corrosion of Reinforcement using RBSM <i>Michihiro TOMIDA, Yasuo KAJIKAWA and Kazutaka KUNO</i>