scholarly journals Numerical Assessment of Reinforced Concrete Beams Strengthened with CFRP Sheets under Impact Loading

2021 ◽  
Vol 15 (58) ◽  
pp. 48-64
Author(s):  
Mohamed Emara ◽  
Nada Elkomy ◽  
Hilal Abdel Kader
Keyword(s):  
Reinforced Concrete ◽  
Impact Velocity ◽  
Impact Loading ◽  
Impact Load ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymers ◽  
Rc Beams ◽  
Cfrp Sheets ◽  
Externally Bonded ◽  
The Impact

This paper investigates numerically the behavior of Reinforced Concrete (RC) beams, strengthened using Carbon Fiber Reinforced Polymers (CFRP) sheets, subjected to impact loading. Three-dimensional finite element analysis was performed and its results were verified against experimental ones available in the literature showing good agreement. Then, a comprehensive parametric study was performed to investigate the effect of studied parameters on the strengthened RC beams. The main studied parameters were type and size of reinforcing bars, geometric characteristics of externally bonded CFRP sheets (width, length, and thickness), impact velocity, and the position of the impactor with respect to the beam. Results showed that the use of externally bonded CFRP sheets enhanced the beam capacity and failure mode, and reduced the mid-span deflection. Moreover, a reduction in the mid-span deflection was observed due to the use of CFRP bars as internal reinforcement. On the other hand, the deflection was increased due to the increase of the impact velocity, and the change of the impact load position.

scholarly journals Mechanical Behavior and Chloride Penetration of Precracked Reinforced Concrete Beams with Externally Bonded CFRP Exposed to Marine Environment

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Yan Xie ◽  
Kunhua Guan ◽  
Lei Zhan ◽  
Qichen Wang
Keyword(s):  
Reinforced Concrete ◽  
Marine Environment ◽  
Chloride Penetration ◽  
Reinforced Concrete Beams ◽  
Bending Test ◽  
Chloride Diffusion ◽  
Accelerated Ageing ◽  
Rc Beams ◽  
Cfrp Sheets ◽  
Externally Bonded

Cracked reinforced concrete (RC) beams can be repaired effectively by using externally bonded CFRP sheets. However, when the strengthened beams are subjected to marine environment, long-term performance will be affected by the material and the interface deterioration of concrete and CFRP. Therefore, to evaluate the service life of the strengthened beams, this study investigates the behavior of precracked RC beams strengthened with CFRP sheets exposed to marine environment. Accelerated ageing experiments were carried out by exposing specimens to cyclic wetting in sea water and drying in 40°C air for 3 months and 6 months, respectively. After the environment exposure, four-point bending test was conducted and then the diffusion of chlorides in the strengthened beams was analysed. The results show that the bonding behavior of the adhesive was weakened and the ductility of the strengthened beams was slightly reduced due to the marine environment. But there is no obvious strength difference between the strengthened beams suffered from marine environment for 3 months and 6 months. Besides, the precracks in the RC beams accelerated the chloride diffusion, while CFRP bonding reduced the chloride penetration. In addition, NEL method was employed to validate the effect of the cracks on chloride permeability. The results showed that the chloride diffusion coefficients increased with the depth of the cracks.

The effect of assembling location on the performance of precast concrete beam under impact load

2017 ◽  
Vol 21 (8) ◽  
pp. 1211-1222 ◽  
Author(s):  
Qiushi Yan ◽  
Bowen Sun ◽  
Xuemei Liu ◽  
Jun Wu
Keyword(s):  
Reinforced Concrete ◽  
Impact Velocity ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Impact Load ◽  
Precast Concrete ◽  
Reinforced Concrete Beams ◽  
Impact Location ◽  
Weight Impact ◽  
The Impact

With incorporation of assembling joints, precast concrete beams could behave very differently in resisting both static and dynamic loads in comparison to conventional reinforced concrete beams. With no research available on the dynamic behavior of precast concrete beams under impact load, a combined experimental and numerical study is conducted to investigate the dynamic response of precast concrete beams under impact load. The results were also compared with reinforced concrete beams. Four groups of concrete beams were tested with all beams designed with the same reinforcement, but different assembling locations were considered for precast concrete beams. The effects of the assembling location in resisting drop weight impact of precast concrete beams were analyzed. The influence of impact mass and impact velocity on the impact resistance of precast concrete beams were also investigated. The results revealed that the further the assembling location is away from the impact location, the closer the mechanical performance of the precast concrete beam is to that of the reinforced concrete beam. When the assembling location and the impact location coincided, the assembling region suffered from severe local damages. With increased impact velocity and impact energy, the damage mode of the precast concrete beams may change gradually from bending failure to bending–shear failure and eventually to local failure. In addition, the bonding around the assembling interface was found to be effective to resist drop weight impact load regardless of the magnitude of the impact velocity and energy.

scholarly journals Effect of Stirrups on Plate End Debonding in Reinforced Concrete Beams Strengthened with Fiber Reinforced Polymers

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3322
Author(s):  
Abdulaziz I. Al-Negheimish ◽  
Ahmed K. El-Sayed ◽  
Mohammed A. Al-Saawani ◽  
Abdulrahman M. Alhozaimy
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Failure Load ◽  
Design Guidelines ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymers ◽  
Rc Beams ◽  
Fiber Reinforced ◽  
Reinforced Polymers ◽  
Cfrp Sheets

Plate end (PE) debonding is one of the critical debonding failure modes that may occur in reinforced concrete (RC) beams strengthened with externally bonded fiber reinforced polymers (FRPs). This study investigated the effect of internal steel stirrups on the PE debonding failure load of FRP-strengthened RC beams. The dimensions of the beams were 3400 × 400 × 200 mm. The beams were strengthened with carbon FRP (CFRP) sheets bonded to the soffit of the beams. The beams were divided into two series based on the distance of the cutoff point of the CFRP sheets from the nearest support. This distance was 50 mm or 300 mm, and the amount of steel stirrups was varied in terms of varying the stirrup diameter and spacing. The beams were simply supported and tested under four-point bending. The test results indicate that the effect of stirrups on the load carrying capacity of the beams was more pronounced for the beams with CFRP sheets extended close to the supports. It was also indicated that beams with larger amounts of stirrups failed in PE debonding by concrete cover separation while beams with lower amounts of stirrups failed in PE by either PE interfacial debonding or critical diagonal crack-induced debonding. The beams were analyzed using several analytical models from design guidelines and the literature. The result of analysis indicates that most of the available models failed to reflect the effect of stirrups in predicting PE debonding failure load of the beams. On the other hand, the models of El-Sayed et al. and Teng and Yao were able to capture such an effect with the best predictions provided by El-Sayed et al. model.

scholarly journals Torsional Strengthening of Reinforced Concrete Beams with Externally-Bonded Fibre Reinforced Polymer: An Energy Absorption Evaluation

2020 ◽  
Vol 6 ◽  
pp. 69-85
Author(s):  
Mahir M. Hason ◽  
Ammar N. Hanoon ◽  
Ahmed W. Al Zand ◽  
Ali A. Abdulhameed ◽  
Ali O. Al-Sulttani
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Energy Absorption ◽  
Structural Damage ◽  
Absorption Capacity ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Concrete Compressive Strength ◽  
Externally Bonded ◽  
The Impact

The impacts of numerous important factors on the Energy Absorption (EA) of torsional Reinforced Concrete (RC) beams strengthened with external FRP is the main purpose and innovation of the current research. A total of 81 datasets were collected from previous studies, focused on the investigation of EA behaviour. The impact of nine different parameters on the Torsional EA of RC-beams was examined and evaluated, namely the concrete compressive strength (f’c), steel yield strength (fy), FRP thickness (tFRP), width-to-depth of the beam section (b/h), horizontal (ρh) and vertical (ρv) steel ratio, angle of twist (θu), ultimate torque (Tu), and FRP ultimate strength (fy-FRP). For the evaluation of the energy absorption capacity at different levels, Response Surface Methodology (RSM) was implemented in this study. Also, to fit the measured results, Quadratic and Line models were created. The results show that the RSM technique is a highly significant tool that can be applied not only to energy absorption-related problems examined in this research, but also to other engineering problems. An agreement is observed between Pareto and standardized charts with the literature showing that the EA capacity of the torsional FRP-RC beams is mostly affected by the concrete compressive strength, followed by the vertical reinforcement ratio. The newly suggested model in this article exhibits a satisfactory correlation co-efficient (R), of about 80%, with an adequate level of accuracy. The obtained results also reveal that the EA acts as a safety index for the FRP-strengthened RC beams exposed to torsional loadings to avoid sudden structural damage. Doi: 10.28991/cej-2020-SP(EMCE)-07 Full Text: PDF

scholarly journals Performance based design of reinforced concrete beams under impact

2010 ◽  
Vol 10 (6) ◽  
pp. 1069-1078 ◽  
Author(s):  
S. Tachibana ◽  
H. Masuya ◽  
S. Nakamura
Keyword(s):  
Reinforced Concrete ◽  
Collision Energy ◽  
Concrete Beams ◽  
Impact Load ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Performance Based Design ◽  
Impact Action ◽  
The Impact ◽  
A Performance

Abstract. The purpose of this research is to collect fundamental data and to establish a performance-based design method for reinforced concrete beams under perpendicular impact load. Series of low speed impact experiments using reinforced concrete beams were performed varying span length, cross section and main reinforcement. The experimental results are evaluated focusing on the impact load characteristics and the impact behaviours of reinforced concrete beams. Various characteristic values and their relationships are investigated such as the collision energy, the impact force duration, the energy absorbed by the beams and the beam response values. Also the bending performance of the reinforced concrete beams against perpendicular impact is evaluated. An equation is proposed to estimate the maximum displacement of the beam based on the collision energy and the static ultimate bending strength. The validity of the proposed equation is confirmed by comparison with experimental results obtained by other researchers as well as numerical results obtained by FEM simulations. The proposed equation allows for a performance based design of the structure accounting for the actual deformation due to the expected impact action.

Test Analysis for RC Beams Strengthened with Externally Bonded Prestressed CFRP Laminates

2008 ◽  
Vol 385-387 ◽  
pp. 41-44 ◽  
Author(s):  
Shi Qi Cui ◽  
Jin Shan Wang ◽  
Zhao Zhen Pei ◽  
Zhi Liu
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Test Results ◽  
Test Analysis ◽  
Cfrp Laminates ◽  
Cfrp Sheet ◽  
Externally Bonded

Reinforced concrete beams strengthened with externally bonded CFRP sheet and prestressed CFRP are analyzed in this paper. Crack developments and displacements with curvatures for different beams are analyzed. Test results show that prestressed CFRP are able to control the development of macro cracks in concrete and prestressed CFRP is an effective method to improve the toughness of concrete, reduce strengthening cost and meanwhile enhance bearing capacity of concrete beams.

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