Article
Polymer Science
Rendy Thamrin, Zaidir Zaidir, Silvy Desharma
Summary: This study experimentally investigated the flexural behavior of RC beams strengthened with CFRP plates, analyzing the impact of the tensile reinforcement ratio, the modulus of elasticity ratio of concrete, the modulus of elasticity of the plate, and the plate thickness on the debonding moment. A simple model for predicting the debonding moment was developed based on statistical analysis, and the effect of these variables on debonding failure was confirmed through parametric studies using fiber elements and the two-dimensional finite element method.
Article
Construction & Building Technology
Dawei Liu, Fengjiang Qin, Jin Di, Zhigang Zhang
Summary: In this study, RC beams were strengthened using CFRP and ECC. Experimental investigation and analytical prediction methods were employed to study the flexural behavior of the strengthened beams. The results showed that the composite use of CFRP and ECC effectively prevented premature delamination and significantly enhanced the load capacities of the beams. The prediction model demonstrated high accuracy with an error variation within 5% when compared to the tested values.
CASE STUDIES IN CONSTRUCTION MATERIALS
(2023)
Article
Mechanics
Guibing Li, Aihui Zhang, Weiliang Jin, Yifei Xiao, Huaying Li
Summary: According to the ACI440.2R and other codes，concrete can achieve a compressive strain of 0.003 without FRP debonding at the ultimate limit state of FRP-strengthened RC beams. However, many flexural tests have shown that intermediate crack (IC) induced debonding is the main failure mode, and the ultimate compressive strain of the concrete cannot reach 0.003, in most cases, even much less than 0.003 at initial debonding of CFRP reinforcements. In addition, the FRP debonding strain limit proposed by the codes cannot effectively prevent debonding failure. A new model is developed based on theoretical analysis and test results to calculate CFRP strain and flexural strength. Six CFRP-strengthened RC beams are tested to investigate the initiation of CFRP debonding and provide clear pictures of the tensile strains, load-carrying capacity, concrete compressive strain, and cracks at the initial debonding. The new model provides a more accurate evaluation of the CFRP strain and flexural strength in beams with IC debonding failure compared to code models.
COMPOSITE STRUCTURES
(2023)
Article
Mechanics
Faisal M. Mukhtar, Mohammed E. Shehadah
Summary: This study investigates the shear behavior and debonding characteristics of initially ductile RC beams transitioning to a more brittle shear failure upon strengthening using external flexural CFRP. A holistic capacity prediction approach that considers the synergistic effect between shear failure and CFRP debonding is provided, instead of solely focusing on shear failure or crack-induced debonding relationship.
COMPOSITE STRUCTURES
(2021)
Article
Mechanics
Feng Zhang, Lei Gao, Yu-Fei Wu, Jinyi Liu
Summary: The development of HB-FRP strengthening technology is a significant breakthrough in structural strengthening, with a well-studied design theory that effectively restricts premature debonding and improves bearing capacity to meet engineers' needs.
COMPOSITE STRUCTURES
(2021)
Article
Engineering, Civil
Khattab Al-Ghrery, Robin Kalfat, Riadh Al-Mahaidi, Nazar Oukaili, Alaa Al-Mosawe
Summary: This study investigates the use of gene expression programming (GEP) to develop a new model for predicting the shear force required to induce FRP CCS failure. A comprehensive database of 127 experimental data points of FRP-strengthened RC beams was compiled. The proposed GEP model showed significantly higher correlations with actual CCS failure loads compared to existing predictive models.
JOURNAL OF COMPOSITES FOR CONSTRUCTION
(2021)
Article
Construction & Building Technology
Mahmoud A. El-Mandouh, Mostafa S. Omar, Ahmed S. Abd El-Maula
Summary: This study investigates the effect of openings on the behavior of flat slabs and the use of CFRP for strengthening. Results show that CFRP can improve the ductility of slabs with openings. Opening located at the column face increases strains in steel reinforcement. Finite Element Method (FEM) via software ANSYS12 can successfully simulate the behavior of slabs with openings strengthened with CFRP.
CASE STUDIES IN CONSTRUCTION MATERIALS
(2021)
Article
Chemistry, Physical
Jongho Park, Sun-Kyu Park, Sungnam Hong
Summary: This study determined the flexural behavior of TRM-strengthened beams by considering intermediate crack debonding, and defined the TRM beam strengthening limit and TRM coefficients based on experimental results of four other research on 22 specimens. It is expected that a conservative design would be possible when applying the suggested strengthening limit coefficient in the future.
Article
Engineering, Mechanical
Liu Jin, Binlin Zhang, Fengjuan Chen, Xiuli Du
Summary: A three-dimensional numerical model was proposed to accurately simulate the mechanical behavior of CFRP-strengthened RC shear wall, considering the effect of strain rate on the constitutive relations. The study investigated the influences of strain rate, CFRP wrapping method, and the number of CFRP layer on the dynamic shear properties and CFRP shear contribution. The results showed that the damage of the shear wall increased with higher strain rates, and the failure pattern and bearing capacity were affected by CFRP layout configurations. The shear contribution of CFRP strips significantly increased under dynamic loads, especially with strain rates exceeding 10-3 /s, enhancing the overall bearing capacity.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Multidisciplinary Sciences
Ahmed S. Eisa, Mostafa H. Ahmed, Ivo Demjan, Dusan Katunsky
Summary: The demand for strengthening and rehabilitation of existing RC structures has increased due to various reasons, and there has been a lack of research on strengthening GPC beams with CFRP sheets. This experimental study investigated the behaviour of GPC beams strengthened with CFRP sheets, and the results showed improved flexural and shear behaviour compared to RC beams. The flexural strengthening increased the load capacity and decreased deflection, while the shear strengthening improved load capacity and shear ductility.
Article
Engineering, Civil
Y. M. Alharthi, M. Emara, A. S. Elamary, I. A. Sharaky
Summary: This study introduces a new technique of strengthening RC beams using a limited steel-bar-reinforced mortar layer (SBRML) to reduce installation time and cost, while combining the advantages of existing techniques. Experimental results demonstrate a significant increase in bearing capacities for RC beams strengthened with different types of SBRML.
ENGINEERING STRUCTURES
(2021)
Article
Construction & Building Technology
W. Nawaz, M. Elchalakani, A. Karrech, S. Yehia, O. Youssf, B. Yang
Summary: The research on retrofitting and strengthening lightweight concrete structures is limited. This study evaluates the flexural performance of lightweight concrete beams externally strengthened using Carbon Fibre Reinforced Polymer (CFRP) sheets and finds that the CFRP sheets significantly increase the ultimate load carrying capacity of the beams.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Construction & Building Technology
Haider Hamad Ghayeb, Rafid Saeed Atea, Muslim Abdul-Ameer Al-Kannoon, Foo Wei Lee, Leong Sing Wong, Kim Hung Mo
Summary: Existing RC slabs often require punching shear reinforcement due to various reasons such as design defects and structural damage. This study investigated the effectiveness of using CFRP strengthening method on two-way RC slabs. The results showed that CFRP strengthening improved the performance of the slabs, delaying crack appearance, enhancing shear crack resistance, and increasing load-displacement and ductility capacities. The analytical model used for predicting punching shear strength also demonstrated good agreement with practical codes.
CASE STUDIES IN CONSTRUCTION MATERIALS
(2023)
Article
Mechanics
Yu Deng, Zhenzhen Li, Hexin Zhang, Alberto Corigliano, Angus C. C. Lam, Chayanon Hansapinyo, Zhitao Yan
Summary: The study found that RC beams strengthened with NSM CFRP-PCPs have higher flexural capacity compared to unstrengthened beams, and increasing the prestress level of the CFRP-PCPs can enhance crack resistance and load capacity. Beams strengthened with CFRP-PCPs made with UHPC showed better performance than those with epoxy resin mortar.
COMPOSITE STRUCTURES
(2021)
Article
Construction & Building Technology
Shitao Cheng, Haoxiang He, Yifei Chen, Bingji Lan
Summary: This study investigates the mechanical properties and crack resistance of reinforced concrete (RC) beams strengthened with textile and modified concrete through theoretical analysis and experimental study. The load-deflection curve and flexural capacity calculation methods are proposed based on force analysis of the cross-section. The shear capacity calculation method based on the truss-arch model and the crack width calculation method based on the bond-slip theory are also proposed. The experimental results confirm the excellent performance and crack control ability of the specimens strengthened with textile and modified concrete.
JOURNAL OF BUILDING ENGINEERING
(2023)
