scholarly journals Debonding Failure Analysis of Reinforced Concrete Beams Strengthened with CFRP Plates

2021 ◽  
Author(s):  
Rendy Thamrin ◽  
Zaidir Zaidir ◽  
Silvy Desharma
Keyword(s):  
Reinforced Concrete ◽  
Modulus Of Elasticity ◽  
Reinforcement Ratio ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymers ◽  
Analytical Prediction ◽  
Rc Beams ◽  
Test Results ◽  
Fiber Element ◽  
Element Method

In this study, experimental work was carried out on reinforced concrete (RC) beams strengthened with carbon fiber reinforced polymers (CFRP) plates. This study aims to examine the effect of the reinforcement ratio on the flexural behavior of these beams and propose a new model for predicting the debonding moment. Six RC beams consisting of three control beams and three beams strengthened with CFRP plates were tested. The beams were simply supported and loaded with four-point bending. The test variable was the tensile reinforcement ratio (1%, 1.5%, and 2.5%). Analytical prediction using the fiber element method was also carried out to obtain the complete theoretical response of the beam due to flexural loads. The test results show that the reinforcement ratio affected the bending performance of RC beams with CFRP plates. Following this, the experimental data from 60 beam test results from published literature and this study were analyzed. From these data, it was found that the ratio of tensile reinforcement, the ratio of modulus of elasticity of concrete, the modulus of elasticity of the plate, and plate thickness all affect the value of debonding moment. A parametric study using fiber element and two-dimensional finite element method was also carried out to confirm the effect of these parameters on debonding failure. These parameters were then used to develop an equation to predict the debonding moment of RC beams strengthened with CFRP plates using simple statistical analysis. This analysis resulted in a simple model for predicting the debonding moment. Then the model is entered into a computer program, and the complete response of the cross-section due to debonding failure can be obtained.

scholarly journals Debonding Failure Analysis of Reinforced Concrete Beams Strengthened with CFRP Plates

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2738
Author(s):  
Rendy Thamrin ◽  
Zaidir Zaidir ◽  
Silvy Desharma
Keyword(s):  
Reinforced Concrete ◽  
Modulus Of Elasticity ◽  
Reinforcement Ratio ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Fiber Reinforced Polymers ◽  
Analytical Prediction ◽  
Rc Beams ◽  
Test Results ◽  
Element Method

In this study, experimental work was carried out on reinforced concrete (RC) beams strengthened with carbon fiber reinforced polymers (CFRP) plates. This study aims to examine the effect of the reinforcement ratio on the flexural behavior of these beams and propose a new model for predicting the debonding moment. Six RC beams consisting of three control beams and three beams strengthened with CFRP plates were tested. The beams were simply supported and loaded with four-point bending. The test variable was the tensile reinforcement ratio (1%, 1.5%, and 2.5%). Analytical prediction using the fiber element method was also carried out to obtain the complete theoretical response of the beam due to flexural loads. The test results show that the reinforcement ratio affected the bending performance of RC beams with CFRP plates. Following this, the experimental data from 60 beam test results from published literature and this study were analyzed. From these data, it was found that the ratio of tensile reinforcement, the ratio of modulus of elasticity of concrete, the modulus of elasticity of the plate, and plate thickness all affect the value of debonding moment. A parametric study using fiber elements and the two-dimensional finite element method was also carried out to confirm the effect of these variables on debonding failure. These variables were then used to develop an equation to predict the debonding moment of RC beams strengthened with CFRP plates, using simple statistical analysis. This analysis resulted in a simple model for predicting the debonding moment. Then the model is entered into a computer program, and the complete response of the cross-section due to debonding failure can be obtained.

scholarly journals BEHAVIOUR OF REINFORCED CONCRETE BEAMS WITHOUT STIRRUPS SUBJECTED TO STEEL REINFORCEMENT CORROSION

2016 ◽  
Vol 22 (2) ◽  
pp. 146-153 ◽  
Author(s):  
Rizwan AZAM ◽  
Ahmed K. EL-SAYED ◽  
Khaled SOUDKI
Keyword(s):  
Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Load Carrying Capacity ◽  
Longitudinal Reinforcement ◽  
Rc Beams ◽  
Test Results ◽  
Structural Behaviour ◽  
Three Point Bending ◽  
Load Carrying ◽  
Crack Widths

The effect of corrosion on the structural behaviour of reinforced concrete (RC) beams without stirrups was experimentally investigated. A total of seven medium-scale RC beams without stirrups were constructed. The beams measured 150 mm wide, 250 mm deep and 1700 mm long. The test variables included: three different longitudinal reinforcement ratios (0.91%, 1.21%, and 1.82%) and two different corrosion levels (3% and 10%). Four beams were subjected to artificial corrosion whereas three beams acted as control un-corroded. Following the corrosion phase, all beams were tested to failure in three point bending. Corrosion crack widths and cracking patterns were recorded at different stages of corrosion. The effect of different longitudinal reinforcement ratios on the rate of corrosion was observed. Test results revealed that the beams with higher reinforcement ratios experienced slower corrosion rate compared to beams with lower reinforcement ratios. All control beams failed in shear whereas corroded beams failed in bond. There was a significant reduction in the load carrying capacity of the corroded beams without stirrups compared to the control beams.

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.

scholarly journals Flexural Strength Design of Hybrid FRP-Steel Reinforced Concrete Beams

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6400
Author(s):  
Binbin Zhou ◽  
Ruo-Yang Wu ◽  
Yangqing Liu ◽  
Xiaohui Zhang ◽  
Shiping Yin
Keyword(s):  
Reinforced Concrete ◽  
Flexural Strength ◽  
Failure Modes ◽  
Reinforcement Ratio ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Strength Reduction Factor ◽  
Steel Reinforced Concrete ◽  
Strength Design ◽  
Reinforced Beams

Through proper arranging of a hybrid combination of longitudinal fiber reinforced polymer (FRP) bars and steel bars in the tensile region of the beam, the advantages of both FRP and steel materials can be sufficiently exploited to enhance the flexural capacity and ductility of a concrete beam. In this paper, a methodology for the flexural strength design of hybrid FRP-steel reinforced concrete (RC) beams is proposed. Firstly, based on the mechanical features of reinforcement and concrete and according to the latest codified provisions of longitudinal reinforcement conditions to ensure ductility level, the design-oriented allowable ranges of reinforcement ratio corresponding to three common flexural failure modes are specified. Subsequently, the calculation approach of nominal flexural strength of hybrid FRP-steel RC beams is established following the fundamental principles of equilibrium and compatibility. In addition to the common moderately-reinforced beams, the proposed general calculation approach is also applicable to lightly-reinforced beams and heavily-reinforced beams, which are widely used but rarely studied. Furthermore, the calculation process is properly simplified and the calculation accuracy is validated by the experimental results of hybrid FRP-steel RC beams in the literature. Finally, with the ductility analysis, a novel strength reduction factor represented by net tensile steel strain and reinforcement ratio is proposed for hybrid FRP-steel RC beams.

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.

The Experimental Study on Bearing Capacity of Reinforced Concrete Structure with Different Reinforce Methods

2014 ◽  
Vol 936 ◽  
pp. 1438-1441
Author(s):  
Qing Yi Liu ◽  
Xiao Mei Liu
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Steel Plate ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Test Results ◽  
Reinforced Concrete Structure ◽  
Fiber Sheet

Three reinforcement materials with steel plate, epoxies resin sheet, and glass fiber sheet adhering to failed reinforced concrete beams (RC beams) were used to improve the bearing capacity of Reinforced Concrete beams in the paper. The test results shows all the three materials were proved satisfied with bearing capacity increasing request. Strengthening effects with steel plate and epoxies resin sheet were more obvious.

scholarly journals Influence of tensile softening of concrete on crack development and failure in concrete and reinforced concrete beams

2019 ◽  
Vol 68 (1) ◽  
pp. 213-223 ◽  
Author(s):  
Marta Słowik
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Load Capacity ◽  
Plain Concrete ◽  
Reinforcement Ratio ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Concrete Members ◽  
Cracking Process ◽  
Tensile Softening

In the paper, the own test results were presented. The experimental investigation was focused at determining the cracking and load capacity of beams made of concrete. The beams were characterized by different longitudinal reinforcement ratio from zero — plain concrete beams, through low ratio 0.12% — slightly reinforced concrete beams, middle ratio 0.9% — typical reinforced concrete beams, up to the ratios 1.3% and 1.8% — higher reinforced concrete beams. On the basis of the performed experiments and the results of numerical calculations, the process of crack’s formation and crack’s development in plain concrete, slightly reinforced concrete and reinforced concrete beams with different reinforcement ratio was described. When discussing cracking process in the beams, the contribution of strain softening of tensile concrete in the microcracked zone on the character of beams’ failure was analysed as well. Keywords: civil engineering, concrete and reinforced concrete members, cracking and load capacity.

Effect of Beam Depth and Longitudinal Reinforcement Ratio on Shear Strength of RC Beams

2010 ◽  
Vol 163-167 ◽  
pp. 1460-1465
Author(s):  
Lei Yu ◽  
Yi Che ◽  
Xin Feng Zheng ◽  
Jin Xin Gong ◽  
Yu Pu Song
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforcement Ratio ◽  
Reinforced Concrete Beams ◽  
Shear Behaviour ◽  
Longitudinal Reinforcement ◽  
Test Results ◽  
Beam Depth ◽  
Insight Into

Seven beams were tested to investigate the effects of beam depth and longitudinal reinforcement ratio on the shear strength of reinforced concrete beams. To investigate the effects of beam depth on shear strength, beams of five different sizes were tested. Two beams were designed to investigate the shear behaviour of beams with small percentage of longitudinal reinforcement. In addition to an experimental investigation, a survey of data in the literature was performed to gain insight into the influence of beam depth and longitudinal reinforcement ratio. Based on test results and a data analysis, conclusions regarding the influence of beam depth and longitudinal reinforcement ratio on shear strength of reinforced concrete beams are presented herein.

scholarly journals The analysis of load carrying capacity and cracking of slightly reinforced concrete members in bending

2008 ◽  
Vol 2 (1) ◽  
pp. 065-078
Author(s):  
Marta Słowik
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Beams ◽  
Plain Concrete ◽  
Reinforcement Ratio ◽  
Reinforced Concrete Beams ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Concrete Members ◽  
Load Carrying

Slightly reinforced concrete members are the members made by concrete with reinforcement less than minimum given in codes for reinforced concrete ones. Plain concrete and slightly reinforced concrete members in bending are treated in the same way during the dimensioning and the influence of longitudinal reinforcement on the load carrying capacity is not taken into account. The mechanism of work and crack formation in slightly reinforced concrete members is not completely recognized. The author’s own research program was made. The experiment was aimed at the determination of cracking moment and load carrying capacity of slightly reinforced concrete beams with different reinforcement ratio. Also plain concrete beams and the typical reinforced concrete beam were tested. The analysis of the obtained values of maximum bending moment and crack’s widths was made according to the reinforcement ratio. The analysis of test results shows how the presence of longitudinal steel bars in concrete members, even when reinforcement ratio is low, changes cracking process and influences the value of cracking moment in flexural members. On the basis of test results, the method how to calculate the load carrying capacity of slightly reinforced concrete elements in bending has been proposed.

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.

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