Flexural strengthening of over-reinforced concrete beams with highly ductile fiber-reinforced concrete layer

Deng, Mingke; Zhang, Min; Ma, Fei; Li, Fang-Yuan; Sun, Hongzhe

doi:10.1016/j.engstruct.2020.111725

Cited by 23 publications

(16 citation statements)

References 31 publications

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“…To avoid the brittle compression failure, many codes limit the use of over-reinforced sections (Ziara, Haldane & Hood, 2000;Siddiqi, 2016). However, a high tensile reinforcement ratio is often used to decrease the size of the beam and to provide adequate stiffness (Whitehead & Ibell, 2004;Ahmed, Farghal, Nagah & Haridy, 2007;Ali & Tarkhan, 2015;Mohamed, 2018;Deng, Zhang, Ma, Li & Sun, 2021). By reducing the beam's size, the formwork dimensions reduce and save time, material, and labor during construction.…”

Section: Introductionmentioning

confidence: 99%

Stress–strain relationship of ductile materials and flexural behavior of ductile over-reinforced concrete beams

DUHAIM¹,

MASHREI²

2022

srees

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This paper aimed to investigate the effect of using ductile materials in the compression zone on the flexural performance of over-reinforced concrete beams. In order to avoid brittle compression failure, partial replacement of concrete with ductile materials layer in the compression zone was used. Four over-reinforced concrete beams of size 120 × 180 × 1,300 mm were cast and tested under three-point loading conditions. The steel fibers reinforced concrete (SFRC), slurry infiltrated fiber concrete (SIFCON), and ultra-high performance fiber reinforced concrete (UHPFRC) were used as ductile materials. The flexural capacity of the beams, failure modes, crack patterns, load-deflection relationships, ductility index, and toughness were investigated. The results showed that using ductile materials in the compression zone is an effective technique to increase the ultimate load, ductility, and toughness by up to 52.46, 84.78 and 279.93%, respectively, compared to the reference beam. In addition, the failure mode changed from brittle to ductile failure. Noting that the use of SFRC layer enhanced the ductility of over-reinforced concrete beams more than using UHPFRC and SIFCON layers. Also, one of the main advantages of this technique is led to increase the tensile reinforcement ratio up to 8.548% without needing the compressive reinforcement. Thus, ductile composite beams with a high flexural capacity were generated using an economical amount of ductile materials.

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Section: Introductionmentioning

confidence: 99%

Stress–strain relationship of ductile materials and flexural behavior of ductile over-reinforced concrete beams

DUHAIM¹,

MASHREI²

2022

srees

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“…Te reinforcement method is shown in Figure 1. Te fnite element model of the RC beam was established, and the fnite element model results were compared with the experimental results in the literature [29]. Te rationality of the fnite element model was verifed by comparison of the loaddefection curve, crack distribution, and failure modes, which is a common research method [30,31].…”

Section: Introductionmentioning

confidence: 99%

Flexural Reinforcement of Over-Reinforced Beam by Ultrahigh Performance Concrete Layer

Yang

Yao

Liu

2022

Mathematical Problems in Engineering

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In order to improve the failure state of over-reinforced beams and enhance their ductility, an innovative reinforcement method was proposed by adding an ultrahigh performance concrete (UHPC) layer on the top surface of the over-reinforced beam to take advantage of the high compressive strength of UHPC. The numerical simulation method was used to carry out the research. The validity of the finite element model was verified by comparing it with the experimental results, and the effectiveness of the new reinforcement method was verified by comparing it with the calculation results after adding the UHPC layer. Then, a detailed parameter study was carried out, including the thickness of the UHPC layer, the cross-section area of longitudinal tension rebar, and concrete strength. The load-deflection curve, flexural bearing capacity, and deflection ductility coefficient were studied. The results show that the bearing capacity of the UHPC-reinforced over-reinforced beams is significantly increased by 88.1%. And the stiffness and ductility of the beams are also significantly increased, with the ductility coefficient reaching 23.85. In addition, flexural bearing capacity increases with the thickness of the UHPC layer and sectional area of longitudinal tension rebar. Finally, a prediction model for the flexural bearing capacity of UHPC layer-reinforced over-reinforced beams is proposed, which further verifies the effectiveness of this method.

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“…Reinforced concrete (RC) members may need strengthening for reasons such as change of usage, increase in service load, aging, and chemical aggressions [1]. On the other hand, much research has been carried out on the strengthening of concrete members due to their extensive use in structures, and various methods and materials have been proposed, such as externally attached steel plates, fiber reinforced polymers (FRP), etc.…”

Section: Introductionmentioning

confidence: 99%

Cement-Based Mortar Panels Reinforced with Recycled Steel Fibers in Flexural Strengthening of Concrete Beams

Zamanzadeh

Hosseinzadeh

Bashiri

2021

Int. j. eng. technol. innov.

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The effectiveness of a strengthening technique devised for the concrete beams subjected to bending is presented in this study, where recycled-steel fiber-reinforced mortar (RSFRM) panels are used as an eco-friendly replacement for ordinary steel fibers. Different mix designs for RSFRM are first investigated experimentally by testing 160 × 400 × 400 mm3 notched beam-like specimens in 3-point bending, while 100 × 100 × 100 mm3 cubes are tested in compression, to optimize the mix design. Finite element (FE) analyses are carried out on strengthened and non-strengthened beams to investigate the effectiveness of the proposed strengthening technique based on RSFRM panels. Starting from the tests on notched beams, an inverse FE analysis is used to optimize the RSFRM’s parameters to be implemented into the numerical model. The results show that applying RSFRM panels not only markedly increases the load-bearing capacity of the beams (up to 3.19 times with 3% of fibers by volume), but also changes their fracture mechanism from brittle to ductile fracture.

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Flexural strengthening of over-reinforced concrete beams with highly ductile fiber-reinforced concrete layer

Cited by 23 publications

References 31 publications

Stress–strain relationship of ductile materials and flexural behavior of ductile over-reinforced concrete beams

Stress–strain relationship of ductile materials and flexural behavior of ductile over-reinforced concrete beams

Flexural Reinforcement of Over-Reinforced Beam by Ultrahigh Performance Concrete Layer

Cement-Based Mortar Panels Reinforced with Recycled Steel Fibers in Flexural Strengthening of Concrete Beams

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