Numerical Study on Nonlinear Behavior of RC Continuous Deep Beams

This paper presents a study of the behavior of reinforced concrete continuous deep beams by numerical simulation, where results of the numerical analysis are calibrated and validated from existing experimental results in the international literature. In the modeling, a bilinear model is considered with Von Mises failure criteria for reinforcing steel and Concrete Damage Plasticity for concrete, where a good correspondence was achieved between the numerical results to estimate the load capacity and the displacement between the reference numerical and experimental results. The adequate calibration of the physical-mechanical diagram of the experiment allows numerically studying the influence of different geometric factors and reinforcement configurations. The numerical study evidences the influence of the main and vertical reinforcements in the load capacity of these structures, where the most significant contribution of the vertical reinforcement is found in beams with higher shear span-effective depth ratio (a/d). Diagrams of continuous deep beams with circular web openings are analyzed, showing favorable positions for the location of these openings and their direct influence on the load capacity reduction for beam diagrams with concentrated and distributed load.

TJES Vol26 No.1 2019, 2019

This study investigates the effect of load eccentricity on the deep beams in terms of failure load and failure mode by using ANSYS nonlinear finite element program. Three RC deep beams with shear span to depth ratios, varying from 0.91 to 1.67 are modeled. The comparison between experimental and numerical result under central load shows approximately fully match between them to ensure that the model was represented correctly. The model has been used to investigate the behavior of RC deep beams under eccentric loads with various heights of beams. Under eccentric load there was significant reduction in failure load. With increasing height of the beams the failure load increased gradually with incremental increases in height, also there is a clear reduction in failure load due to eccentricity. But when the eccentricity of the load on the beams reaches 50 mm all beams of different heights possess the same failure load and all of them are failed due to concrete crushing at the beam compr...

According to ACI 318M-14[1] Code, deep beams can be defines as: Members loaded on one face and supported on the opposite face so that compression struts can develop between the loads and the supports. While shallow beams is the member not controlled by direction load and lower capacity from deep beams. Commonly used as load distribution elements such as pile caps, transfer girders,tanks, foundation walls, and folded plate. Mainly, the use of deep beams in tall buildings at the lower levels for both commercial and residential purposes. Continuous deep beams show a separate 'truss' or 'tied arch' behaviour that not created in continuous slender beams. In continuous deep beams, on the other hand, most of the forces are transferred to the supporting points through separate direct compression struts. Generally, deep beams strength controlled by shear rather than flexure.Moreover, the deep beams shear strength is meaningfully larger than that expected using expressions developed for shallow beams.Previous studies have concluded that The ultimate shear strength increases significantly with increasing web reinforcement ,compressive strength , maximum size aggregate and decreasing shear span to overall depth ratio also presence of openings within the natural load path leads to a significant reduction in capacity.

International Journal of Engineering, 2019

Reinforced Concrete (RC) deep beams are commonly used in structural design to transfer vertical loads when there is a vertical discontinuity in the load path. Due to their deep geometry, the force distribution within the RC deep beams is very different than the RC shallow beams. T here are some strut and tie model (STM) already been developed for RC deep beams. However, most of these models are developed for RC deep beams with the simply supported boundary condition, which do not apply for RC deep beams with the fix-ended condition. In this paper, five fixed-end RC deep beams have been tested experimentally which were subjected to monotonic and cyclic loads. Also, a simple ST M was proposed to simulate the load capacity and failure mode of fix-ended RC deep beams. T he proposed ST M has the main strut and sub struts to simulate the force distribution within the RC deep beams. T his ST M were verified using five fixed-end RC deep beams subjected to monotonic and cyclic loads and compared to the response of 31 additional independent experimental tests. T he result shows the newly proposed ST M can simulate the load capacity and failure mode of fix-ended RC deep beams very well.

International Journal of Structural Engineering, 2020

In this paper, the behaviour of reinforced concrete (RC) elements has been studied and a new shear stress-strain (SS-S) model is proposed for RC deep beams. Timoshenko beam theory is applied to consider the effect of shear deformations in numerical models. To take into account, the effect of barconcrete interaction, the deep beam is divided into several sub-elements, and individual degrees of freedom are assigned to bars, which allow them to act independently. Since SS-S model is highly sensitive to several factors, a numerical definition of RC deep beams' shear behaviour is presented after assessing the contribution of main effective parameters on RC element's shear behaviour. The mentioned model is a push curve which has three breaking points. Proposed SS-S model is composed of several mathematical equations which allows users to easily predict the shear behaviour of RC deep beams without dealing with complex and time-consuming calculations.

Test results of nine reinforced concrete continuous deep beams are presented and analyzed. The main variables studied were shear span-to-depth ratio (a/d), vertical web reinforcement ratio (ρ v), horizontal web reinforcement ratio (ρ h), and concrete compressive strength (f cu). The results of this study show that the stiffness reduction was prominent in case of lower concrete strength and higher shear span-to depth ratio and that the variation of strains along the main longitudinal top and bottom bars was found to be dependent on the shear span-to depth ratio. For beams having small (a/d) ratio, horizontal shear reinforcement was always more effective than vertical shear reinforcement. Finally, the obtained test results are compared to the predictions of finite element analysis using the ANSYS 10 program and a well agreement between the experimental and analytical results was found.

Tikrit Journal of Engineering Sciences, 2019

This study investigates the effect of the load eccentricity on the deep beams, in terms of failure load and failure mode, using ANSYS nonlinear finite element program. Three RC deep beams with shear span to depth ratios, varying from 0.91 to 1.67 are modeled. A comparison between the experimental and numerical results, under central load, showed approximately full matching between them. This had been done in order to ensure that the model was represented properly. The used model for investigating the behavior of the RC deep beams under an eccentric load with various heights of beams showed that under eccentric load there was a significant reduction in the failure load. Increasing the beams height cause of an increase (gradually) of the failure load with the incremental increases of the height, also there was a clear reduction in the failure load due to eccentricity. For the load eccentricity value 50 mm all the beams of different heights possess the same failure load and all of them failed due to concrete crushing at the beam compression face.

2005

A comparative study on RC deep beams behavior is conducted in this paper by means of Japanese design codes (JSCE and JRA) prediction and finite element analysis and those results are evaluated by experimental observation. The beams have shear span to depth ratio between 0.5 and 1.5 and effective depth size from 400 mm to 1400 mm. Lateral reinforcement ratio varies by 0.0%, 0.4% and 0.8% in shear span. Estimated shear capacity by JSCE was around shear crack load while JRA code and Finite Element analysis have had closer results to experiment.

Revista de la construcción

In this paper is carried out a study to the behavior of reinforced concrete deep beams by numerical simulation, where the results of numerical analysis are calibrated and validated from existing experimental results in the international literature. In modelling is considered a bilinear model with Von Mises failure criteria for steel and Concrete Damage Plasticity for concrete, achieving an appropriate match between the numerical results against the experimental reference, a feature that allows the parametric study of the influence of geometric factors and reinforcement. Two formulas for estimating the ultimate shear strength of reinforced concrete deep beams under static load with predominance of shear strength as proposed, which are based on empirical models developed from the processing of a large and profuse database where experimental results of the numerical simulation are included. These formulations show adequate accuracy in predicting the ultimate shear strength in these structures compared with some methods implemented on existing codes ACI Comitee 318 (2011) and European Standard EN 1992-1-1 (2004).

Journal of Structural Engineering, 2000

Reinforced Concrete (RC) deep beams are commonly used in structural design to transfer vertical loads when there is a vertical discontinuity in the load path. Due to their deep geometry, the force distribution within the RC deep beams is very different than the RC shallow beams. T here are some strut and tie model (STM) already been developed for RC deep beams. However, most of these models are developed for RC deep beams with the simply supported boundary condition, which do not apply for RC deep beams with the fix-ended condition. In this paper, five fixed-end RC deep beams have been tested experimentally which were subjected to monotonic and cyclic loads. Also, a simple ST M was proposed to simulate the load capacity and failure mode of fix-ended RC deep beams. T he proposed ST M has the main strut and sub struts to simulate the force distribution within the RC deep beams. T his ST M were verified using five fixed-end RC deep beams subjected to monotonic and cyclic loads and compared to the response of 31 additional independent experimental tests. T he result shows the newly proposed ST M can simulate the load capacity and failure mode of fix-ended RC deep beams very well.

Journal of Asian Architecture and Building Engineering, 2011

Two design approaches, conventional and strut-and-tie procedures, are developed for reinforced concrete continuous deep girders which transmit the gravity load from the upper wall to the lower columns. This paper presents the results of tests and analyses conducted on two specimens; the first specimen employs the conventional procedure, while the strut-and-tie procedure is used for the second specimen. The conclusions are as follows: (1) The approach of the strut-and-tie method is valid for this type of continuous deep girder rather than the conventional beam approach. (2) Since the upper load is carried over directly to the supporting column through the stiff concrete strut to the point of yielding of the bottom ties, the shear capacity of continuous deep girders is mainly governed by the yielding forces of the bottom ties. (3) The additional shear resistance derives from continuity with the adjacent beams or walls. Shear and top reinforcements in the continuity region can be designed by using appropriate models for the additional margin of safety in terms of strength and ductility. (4) Simulation through two-dimensional nonlinear analyses using DIANA shows a good correlation with the experimental results.

2015

This research presents an experimental study of shear behavior of RC deep box beam strengthened internally by reinforced concrete transverse ribs. Eight beam specimens were tested, six box-deep beams and two solid-deep beams. The effect of type of concrete (NSC and SCC) and the number of internal cells on the behavior of deep box beam were tested. All beams were (2000mm) long and have been tested over a clear span of (1900mm) with a width of (450 and 200 mm) for top and bottom flanges respectively and (500mm) depth, the shear span-depth ratio (a/d) was (2) and longitudinal reinforcement ratio (ρ) was (0.00835). All beam specimens were simply supported under the effect of single point loading at mid span. The beam length, shear span-depth ratio (a/d), longitudinal and transverse reinforcement were kept constant for all tested beams. Test results indicated that all tested beams failed by shear and the failure took place by diagonal splitting mode for all tested beams except one beam, ...

Structures, 2020

Reinforced Concrete (RC) deep beams are commonly used in structural design to transfer vertical loads when, there is a vertical discontinuity in the load path. Due to their deep geometry, force distribution within the RC deep beams is very different from RC shallow beams. There are some Strut-and-Tie Models (STM) developed for RC deep beams. However, most of these models are developed for RC deep beams with simply supported boundary condition, not applying for RC deep beams with fixed-ended condition. In this paper, a novel curved STM was developed to simulate load capacity and failure mode of fixed-ended RC deep beams subjected to monotonic and cyclic point loads. Curved STM has double main struts and fan-shaped sub struts to simulate force distribution within the RC deep beams. Parameters of curved STM were calibrated using 5 fixed-ended RC deep beams subjected to monotonic and cyclic loads. Then, Calibrated model was compared to responses obtained from 31 additional independent experimental tests. Results showed that newly proposed curved STM is able to simulate load capacity and failure mode of fixed-ended RC deep beams very well.

Journal of Engineering

Nonlinear finite element simulation was once employed to look into the behavior of horizontally curved reinforced concrete deep beams under concentrated load at its mid-span. The study focused on the parametric impact of span length-to-depth (L/D) and span length-to-radius (L/R) ratios. In addition, the effect of longitudinal and spacing of shear reinforcement on the behavior of the beam has been investigated. The study considered sixteen beam specimens. Three of these specimens were straight beams as a control, and others were curved beams. The concrete-damaged plasticity model has been used to model the beam with C-25 grade concrete and steel reinforcements having diameters of ∅ 4 mm, ∅ 10 mm, and ∅ 12 mm with 568 MPa, 596 MPa, and 643 MPa steel grade, respectively. Reduced twenty-noded brick (C3D20 R) and two-noded (T3D2) elements have been used for modeling concrete and steel, respectively. The ultimate load capacity, the strain distribution, the load-deflection curve, and the l...

Port-Said Engineering Research Journal

A nonlinear strain compatibility model is considered to investigate the behavior of reinforced concrete deep beams. It is based on satisfying equilibrium of stresses and compatibility of strains at all layers of the beam cross-section. A VISUAL BASIC code is developed for this model. Strain distribution over the cross section depth in deep beams is different from shallow beams, and varies according to the case of loading, the span-to-depth ratio (L/h), and the structural system. The experimental values of strain over the cross-section depth for different cases for simply supported deep beams, are extracted from the available literature. Based on these values, simplified equations for strain profiles for each case is proposed to use them in the present model. A key feature of the model is the ability to illustrate the effect of shear deformation of the cross section. The model is validated by comparing predicted results with experimental ones from literature in terms of load-displacement.