scholarly journals Load-Deflection Behavior of Over- and Under-Reinforced Concrete Beams with Hybrid FRP-Steel Reinforcements

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5341
Author(s):  
Saruhan Kartal ◽  
Ilker Kalkan ◽  
Ahmet Beycioglu ◽  
Magdalena Dobiszewska
Keyword(s):  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Modulus Of Rupture ◽  
Accurate Estimation ◽  
Secant Modulus ◽  
Reinforced Beams ◽  
Hybrid Beams ◽  
Frp Reinforcement ◽  
Experimental Values ◽  
Curve Equation

The present study pertains to the load-deflection behavior and cracking moments of concrete beams with hybrid FRP-steel reinforcement. Under and over-reinforced hybrid beams were tested for failure along with reference beams with only steel or FRP reinforcement. The first-cracking moments of the beams were estimated analytically by using different uncracked moments of the inertia and modulus of rupture definitions. The uncracked moment of inertia definitions include the gross and uncracked transformed moments. The adopted modulus definitions are comprised of the experimental values from tests on prisms and the analytical values from the equations in different concrete codes. Furthermore, analytical methods were developed for estimating the deflections of concrete beams with hybrid FRP-steel or only FRP reinforcement. Two different types of elastic moduli, namely the secant modulus corresponding to the extreme compression fiber strain and the ACI 318M-19 modulus, were used in deflection calculations. Closer estimates were obtained by using the secant modulus, particularly in hybrid-reinforced beams. In the post-yielding region of the steel tension reinforcement, the deflection estimates were established to lay in closer proximity to the experimental curve when obtained by adding up the deflection increments instead of directly calculating the total deflections from the elastic curve equation. Accurate estimation of the cracking moment was found to be vital for the close prediction of deflections.

scholarly journals A Comparative Study on the Flexural Behaviour of Rubberized and Hybrid Rubberized Reinforced Concrete Beams

2019 ◽  
Vol 5 (5) ◽  
pp. 1052-1067 ◽  
Author(s):  
Hasan Aied Alasmari ◽  
B. H. Abu Bakar ◽  
A. T. Noaman
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Modulus Of Rupture ◽  
Double Layers ◽  
Flexural Behaviour ◽  
Strain Capacity ◽  
Failure Patterns ◽  
Ductility Index ◽  
Hybrid Beams

This paper aims to investigate the flexural behaviour of the rubberized and hybrid rubberized reinforced concrete beams. A total of fourteen beams, 150×200 mm in cross-section with 1000 mm in length, were subject to a laboratory test over an effective span of 900 mm. The sand river aggregate was replaced by 10%, 12.5%, and 15% of crumb rubber (volume).   The hybrid structure contained two double layers: 1) rubberized reinforcement concrete at the top layer of the beam and 2) reinforcement concrete at the bottom layer of the concrete beam. The static responses by the flexural test of all the beams were evaluated in terms of their fresh properties, failure patterns, total energy, flexural strength, stiffness, and ultimate deflection, modulus of rupture, strain capacity, and ductility index. The results showed that there were improvements when the hybrid beams were used in most cases such as failure pattern, ultimate load, stiffness, modulus of rupture, and stress. The rubberized concrete beams showed improvements in the strain capacity as illustrated in strain gauges and stress-strain curves, toughness, ultimate deflection, and ductility index. The findings of the study revealed an improved performance with the use of the hybrid beams. This has resulted in the implementation of innovative civil engineering applications in the engineering sustainable structures.

Strengthening of Reinforced Concrete Beams by Carbon Fiber Composites

2018 ◽  
Vol 931 ◽  
pp. 379-384
Author(s):  
Yuri V. Ivanov ◽  
Yuri F. Rogatnev ◽  
Igor I. Ushakov
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Bearing Capacity ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Carbon Fiber Composites ◽  
Limiting State ◽  
Reinforced Plastics ◽  
Reinforced Beams ◽  
The Given

The paper considers the results of the experimental study of the reinforced concrete beams strengthened by carbon fiber reinforced plastics (the CFRP). Eight reinforced concrete beams of the 80x160 mm section and 1500 mm designed span have been manufactured and tested. The influence of the number of the CFRP layers (strengthening power) on bearing capacity and rigidity under the static loading of beams in the thirds of the span has been studied. The results obtained indicate the increase in bearing capacity of the reinforced beams from 24% up to 55% and the increase in rigidity by 45% for the commonly adopted limiting state, i.e. achieving ultimate deformations in concrete of the compressed zone). The paper underlines the need for using anchor devices in the form of U-shaped binders to ensure the efficiency of the given method of strengthening.

scholarly journals Strengthening Reinforced Concrete Beams with CFRP and GFRP

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Mehmet Mustafa Önal
Keyword(s):  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Strength Increase ◽  
Fiber Reinforced ◽  
Flexural Stress ◽  
Four Point Bending ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Reinforced Beams

Concrete beams were strengthened by wrapping the shear edges of the beams twice at 45° in opposite directions by either carbon fiber reinforced polymer (CFRP) or glass fiber reinforced polymer (GFRP). The study included 3 CFRP wrapped beams, 3 GFRP wrapped beams, and 3 control beams, all of which were 150×250×2200 mm and manufactured with C20 concrete and S420a structural steel at the Gazi University Technical Education Faculty labs, Turkey. Samples in molds were cured by watering in the open air for 21 days. Four-point bending tests were made on the beam test specimens and the data were collected. Data were evaluated in terms of load displacement, bearing strength, ductility, and energy consumption. In the CFRP and GFRP reinforced beams, compared to controls, 38% and 42%, respectively, strength increase was observed. In all beams, failure-flexural stress occurred in the center as expected. Most cracking was observed in the flexural region 4. A comparison of CFRP and GFRP materials reveals that GFRP enforced parts absorb more energy. Both materials yielded successful results. Thicker epoxy application in both CFRP and GFRP beams was considered to be effective in preventing break-ups.

Research on Influences of the Coarse Aggregate Size on the Cracks of the Reinforced Beam

2012 ◽  
Vol 503-504 ◽  
pp. 832-836
Author(s):  
Hong Quan Sun ◽  
Jun Ding
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Coarse Aggregate ◽  
Concrete Beams ◽  
Fractal Theory ◽  
Aggregate Size ◽  
Reinforced Concrete Beams ◽  
Static Loads ◽  
Reinforced Beams ◽  
Maximum Crack

This paper gives the influences of the coarse aggregate size on the cracks of the beam with different aggregate sizes under static loads. The coarse aggregate sizes are ranked into three classes: small size (4.75mm ~ 19mm), big size (19mm ~ 37.5mm) and mixed size (4.75mm ~ 37.5mm). The developments of cracks of three reinforced concrete beams with the different of coarse aggregate sizes under the static loads are researched. The results show that under the action of the same loads, The reinforced concrete beams with the big aggregate size and mixed aggregate size have almost the same maximum crack width, while the maximum crack width of the beam with small aggregate size is less than formers. Using fractal theory, the fractal dimension of the cracks is studied. The result shows that the aggregate sizes have significant effect to the cracks on the reinforced beams.

Crack Analysis on Reinforced Concrete Beams Strengthened by Externally Prestressing Vertical Tensioning Method

2012 ◽  
Vol 204-208 ◽  
pp. 3104-3113
Author(s):  
Bo Wen Shi ◽  
Tian Wen Wang
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Tension Zone ◽  
Stress Mode ◽  
Reinforced Beams ◽  
Internal Forces ◽  
Externally Prestressing ◽  
Resistance Equation

In this paper, seven reinforced concrete beams (two contrast beams and five externally reinforced beams) were tested. The crack regularity under different tension stresses was analyzed through experimental data. Taking the stress mode under pressure for the triangle area, in the tension zone in the shape of a trapezoid , the crack resistance equation of externally prestressing reinforced rectangle beam is derived from balance method of the internal forces and moment, and the results coincide with the experiment results well.

RESULTS OF EXPERIMENTAL RESEARCH OF REINFORCED CONCRETE BEAMS RESISTANCE IN THE ZONE OF SHEAR BENDING

2017 ◽  
Vol 7 (4) ◽  
pp. 25-31
Author(s):  
Valery B. FILATOV ◽  
Vladislav O. GORYNTSEV ◽  
Valery P. BINDER
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Longitudinal Section ◽  
Reinforced Concrete Beams ◽  
Calculation Methods ◽  
Design Standards ◽  
Testing Data ◽  
Failure Loads ◽  
Experimental Values ◽  
Shear Bending

The results of an experimental study of the strength and stress-strain state of reinforced concrete beams in the zone of shear bending are presented. The study was carried out on samples with a small percentage of longitudinal section reinforcement. The technique of testing, data on the rigidity and crack resistance of test specimens under loading, the nature of their destruction are presented. Comparison of experimental values of failure loads with calculated values obtained by the methods of domestic and foreign design standards is performed. It is shown that the empirical basis of the calculation methods limits the range of satisfactory correspondence between the calculated and experimental values of the strength of inclined sections of reinforced concrete beams under the action of shear forces. The conclusion is made about the need to improve the design models to ensure the constructive safety of design solutions.

scholarly journals Ultimate Shear of RC Beams with Corroded Stirrups and Strengthened with FRP

Buildings ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 34 ◽  
Author(s):  
Nino Spinella ◽  
Piero Colajanni ◽  
Antonino Recupero ◽  
Francesco Tondolo
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Effective Strain ◽  
Stress Rupture ◽  
Reinforced Concrete Beams ◽  
Good Ability ◽  
Proposed Model ◽  
Frp Reinforcement ◽  
Corrosion Of Steel

Transverse reinforcement plays a key role in the response behavior of reinforced concrete beams. Therefore, corrosion of steel stirrups may change the failure mode of elements from bending to shear, leading to a brittle and catastrophic crisis. It is important to strengthen reinforced concrete beams with corroded stirrups to enhance the shear resistance. This paper presents a formulation, based on the modified compression field theory, to estimate the ultimate shear of reinforced concrete beams strengthened with FRP, because of stirrup corrosion. The detrimental effect of corrosion on steel stirrup yield strength was taken into account by introducing an empirical decay law. The effective strain of FRP reinforcement was adequately evaluated by considering both debonding and tensile stress rupture. The proposed model was validated against collected experimental results, showing a good ability to evaluate shear strength. Moreover, a numerical analysis was carried out to highlight the role of the key parameters predicting the ultimate shear.

scholarly journals Development methodology of determinating residual carrying capacity of reinforced concrete beams with damages tensile reinforcement which occurred during loading

2021 ◽  
Vol 4 (7(112)) ◽  
pp. 6-17
Author(s):  
Pavlo Vegera ◽  
Rostyslav Vashkevych ◽  
Yaroslav Blikharskyy ◽  
Roman Khmil
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Concrete Beams ◽  
Variable Parameter ◽  
Load Level ◽  
Reinforced Concrete Beams ◽  
New Approach ◽  
Development Methodology ◽  
Experimental Values ◽  
Strain Model

This paper reports the improved and verified procedure for calculating reinforced concrete beams affected by damage to stretched reinforcement when loaded. The main results from testing the reinforced concrete beams with damage in the stretched zone in the form of one hole in the reinforcement in the middle of the beam are given. The variable parameter of the study was the level of load resulting in the damage. It acquired values of 0, 30 %, 50 %, 70 % of the bearing capacity of control undamaged samples. Overall, the results of testing 12 samples are given. A new procedure has been proposed for taking into consideration changes in the mechanical characteristics of stretched reinforcement arising from its damage. This makes it possible to more accurately establish the bearing capacity of reinforced concrete bended elements affected by damage to their reinforcement during operation. The analysis of the calculation, compared with experimental quantities, led to a conclusion that the strain model could determine when the bearing capacity of reinforced concrete beams without damage and with damage to working reinforcement is exhausted. Based on the improved algorithm, the principle of using a strain model was proposed to establish when the bearing capacity of damaged samples, taking into consideration the effect of the load level, is exhausted. The theoretical estimation, considering when the bearing capacity is exhausted, showed results that are 3...21 % less than the experimental values, which ensures reliability of calculation of such structures. The proposed calculation provides a new approach to determining the bearing capacity of reinforced concrete beams damaged during operation. That, in turn, makes it possible to more accurately determine the residual bearing capacity of structures and increases the safety of their operation.

A Method for Calculating Cracking Moment of FRP Reinforced Concrete Beam

2021 ◽  
Vol 896 ◽  
pp. 141-147
Author(s):  
Duy Nguyen Phan
Keyword(s):  
Reinforced Concrete ◽  
Modulus Of Elasticity ◽  
Parametric Study ◽  
Concrete Beams ◽  
Reinforced Concrete Beam ◽  
Reinforcement Ratio ◽  
Reinforced Concrete Beams ◽  
Comparison Results ◽  
Study Results ◽  
Frp Reinforcement

This paper presents an analytical method for calculating the cracking moment of concrete beams reinforced with fiber reinforced polymer (FRP) bars, which considers the non-linear behavior of concrete in the tension zone and the contribution of FRP reinforcement. Theoretical cracking moments obtained by the proposed method were verified with the experimental results and the theoretical results calculated according to ACI 440.1R-15. The comparison results show good agreement between theoretical and experimental data. A parametric study on the effect of longitudinal FRP reinforcement ratio and elastic modulus of FRP on the cracking moment of FRP reinforced concrete beams also were done by using the proposed method. The parametric study results show that both longitudinal reinforcement and modulus of elasticity of FRP significantly affect the cracking moment of FRP reinforced concrete beams. Moreover, parametric study results also clarify the weakness of ACI 440.1R-15 in determining the cracking moment of concrete beams reinforced with a large amount of FRP reinforcement ratio and with high modulus of elasticity of FRP.

Flexural behaviour of ECC and ECC–concrete composite beams reinforced with hybrid FRP and steel bars

2021 ◽  
pp. 136943322110203
Author(s):  
Fang Yuan ◽  
Ren Hu
Keyword(s):  
Corrosion Resistance ◽  
Reinforced Concrete ◽  
Failure Modes ◽  
Concrete Beams ◽  
Steel Corrosion ◽  
High Strength ◽  
Reinforced Concrete Beams ◽  
Flexural Behaviour ◽  
Reinforced Beams ◽  
Load Carrying

Owing to the good ductility of steel and high strength and excellent corrosion resistance of fibre-reinforced polymer (FRP), concrete beams reinforced with hybrid steel and FRP bars exhibit better ductility than FRP-reinforced concrete beams as well as higher load-carrying capacities and better corrosion resistance than steel-reinforced concrete beams. However, the inherent brittleness of concrete in tension results in steel corrosion because of wide cracks and accelerated fracture of FRP reinforcement because of crack-induced stress concentration. This study investigated the effects of ultra-high ductile engineered cementitious composites (ECCs) on the flexural behaviour of hybrid steel and FRP-reinforced beams. Six hybrid-reinforced beams with various reinforcement ratios, matrix types and ECC pouring positions were tested in four-point bending. The flexural behaviours of the beams in terms of failure modes, crack patterns and developments, load versus deformation relationships and ductility are discussed herein in detail. We observed that substituting ECC with concrete results in a higher load-carrying capacity and better ductility of the hybrid reinforced beams owing to the excellent characteristics of ECC materials. When a layer of ECC is poured in the tension zone, the average crack width and crack spacing along the beam decrease; therefore, the longitudinal reinforcements can be adequately protected.

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