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Article
Publication date: 1 October 2003

H.Y. Leung and R.V. Balendran

Use of fibre‐reinforced polymer (FRP) composite rods, in lieu of steel rebars, as the main flexural reinforcements in reinforced concrete (RC) beams have recently been…

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Abstract

Use of fibre‐reinforced polymer (FRP) composite rods, in lieu of steel rebars, as the main flexural reinforcements in reinforced concrete (RC) beams have recently been suggested by many researchers. However, the development of FRP RC beam design is still stagnant in the construction industry and this may be attributed to a number of reasons such as the high cost of FRP rods compared to steel rebars and the reduced member ductility due to the brittleness of FRP rods. To resolve these problems, one of the possible methods is to adopt both FRP rods and steel rebars to internally reinforce the concrete members. The effectiveness of this new reinforcing system remains problematic and continued research in this area is needed. An experimental study on the load‐deflection behaviour of concrete beams internally reinforced with glass fibre‐reinforced polymer (GFRP) rods and steel rebars was therefore conducted and some important findings are summarized in this paper.

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Structural Survey, vol. 21 no. 4
Type: Research Article
ISSN: 0263-080X

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Article
Publication date: 1 October 2018

Jiawei Wang, Jinliang Liu, Guanhua Zhang and Yanmin Jia

The calculation of the shear capacity of inclined section for prestressed reinforced concrete beams is an important topic in the design of concrete members. The purpose of…

Abstract

Purpose

The calculation of the shear capacity of inclined section for prestressed reinforced concrete beams is an important topic in the design of concrete members. The purpose of this paper, based on the truss-arch model, is to analyze the shear mechanism in prestressed reinforced concrete beams and establish the calculation formula for shear capacity.

Design/methodology/approach

Considering the effect of the prestressed reinforcement axial force on the angle of the diagonal struts and regression coefficient of softening cocalculation of shear capacity is established. According to the shape of the cracks of prestressed reinforced concrete beams under shear compression failure, the tie-arch model for the calculation of shear capacity is established. Shear-failure-test beam results are collected to verify the established formula for shear bearing capacity.

Findings

Through theoretical analysis and experimental beam verification, it is confirmed in this study that the truss-arch model can be used to analyze the shear mechanism of prestressed reinforced concrete members accurately. The calculation formula for the angle of the diagonal struts chosen by considering the effect of prestress is accurate. The relationship between the softening coefficient of concrete and strength of concrete that is established is correct. Considering the effect of the destruction of beam shear plasticity of the concrete on the surface crack shape, the tie-arch model, which is established where the arch axis is parabolic, is applicable.

Originality/value

The formula for shear capacity of prestressed reinforced concrete beams based on this theoretical model can guarantee the effectiveness of the calculation results when the structural properties vary significantly. Engineers can calculate the parameters of prestressed reinforced concrete beams by using the shear capacity calculation formula proposed in this paper.

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International Journal of Structural Integrity, vol. 9 no. 5
Type: Research Article
ISSN: 1757-9864

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Article
Publication date: 2 July 2020

Toqa AL-Kasasbeh and Rabab Allouzi

This research is part of a project that aims to investigate using foamed concrete structurally in houses. Foamed concrete has a porous structure that makes it light in…

Abstract

Purpose

This research is part of a project that aims to investigate using foamed concrete structurally in houses. Foamed concrete has a porous structure that makes it light in weight, good in thermal insulation, good in sound insulation and workable.

Design/methodology/approach

An experimental program is conducted in this research to investigate the behavior of polypropylene fiber reinforced foam concrete beams laterally reinforced with/without glass fiber grid.

Findings

The results proved the effectiveness and efficiency of using glass fiber grid as lateral reinforcements on the shear strength of reinforced foam concrete ribs, in reducing the cracks width and increasing its shear capacity, contrary to using glass fiber grid of reinforced foam concrete beams since glass fiber grid did not play good role in beams.

Originality/value

Limited literature is available regarding the structural use of foam concrete. However, work has been done in many countries concerning its use as insulation material, while limited work was done on structural type of foam concrete.

Details

International Journal of Structural Integrity, vol. 12 no. 3
Type: Research Article
ISSN: 1757-9864

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Article
Publication date: 1 June 1997

Jaroslav Mackerle

Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the…

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Abstract

Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore aims to give the reader an encyclopaedic view on the subject. The bibliography at the end of the paper contains 2,025 references to papers, conference proceedings and theses/dissertations dealing with the analysis of beams, columns, rods, bars, cables, discs, blades, shafts, membranes, plates and shells that were published in 1992‐1995.

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Engineering Computations, vol. 14 no. 4
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 3 February 2020

Utino Worabo Woju and A.S. Balu

Performance of the structure depends on design, construction, environment, utilization and reliability aspects. Other factors can be controlled by adopting proper design…

Abstract

Purpose

Performance of the structure depends on design, construction, environment, utilization and reliability aspects. Other factors can be controlled by adopting proper design and construction techniques, but the environmental factors are difficult to control. Hence, mostly in practice, the environmental factors are not considered in the analysis and design appropriately; however, their impact on the performance of the structures is significant along with the design life. It is in this light that this paper aims to perform the time-dependent performance analysis of reinforced concrete structures majorly considering environmental factors.

Design/methodology/approach

To achieve the intended objective, a simply supported reinforced concrete beam was designed and detailed as per the Euro Code (EC2). The time-dependent design parameters, corrosion parameters, creep and shrinkage were identified through thorough literature review. The common empirical equations were modified to consider the identified parameters, and finally, the time-dependent performance of reinforced concrete beam was performed.

Findings

Findings indicate that attention has to be paid to appropriate consideration of the environmental effect on reinforced concrete structures. In that, the time-dependent performance of reinforced concrete beam significantly decreases with time due to corrosion of reinforcement steel, creep and shrinkage.

Originality/value

However, the Euro code, Ethiopian code and Indian code threat the exposure condition of reinforced concrete by providing corresponding concrete cover that retards the corrosion initiation time but does not eliminate environmental effects. The results of this study clearly indicate that the capacity of reinforced concrete structure degrades with time due to corrosion and creep, whereas the action on the structure due to shrinkage increases. Therefore, appropriate remedial measures have to be taken to control the defects of structures due to the environmental factors to overcome the early failure of the structure.

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Journal of Engineering, Design and Technology , vol. 18 no. 5
Type: Research Article
ISSN: 1726-0531

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Article
Publication date: 3 January 2017

Shamsad Ahmad

This study aims to make an effort to develop a model to predict the residual flexural strength of reinforced concrete beams subjected to reinforcement corrosion.

Abstract

Purpose

This study aims to make an effort to develop a model to predict the residual flexural strength of reinforced concrete beams subjected to reinforcement corrosion.

Design/methodology/approach

For generating the required data to develop the model, a set of experimental variables was considered that included corrosion current density, corrosion duration, rebar diameter and thickness of concrete cover. A total of 28 sets of reinforced concrete beams of size 150 × 150 × 1,100 mm were cast, of which 4 sets of un-corroded beams were tested in four-point bend test as control beams and the remaining 24 sets of beams were subjected to accelerated rebar corrosion inducing different levels of corrosion current densities for different durations. Corroded beams were also tested in flexure, and test results of un-corroded and corroded beams were utilized to obtain an empirical model for estimating the residual flexural strength of beams for given corrosion current density, corrosion duration and diameter of the rebars.

Findings

Comparison of the residual flexural strengths measured experimentally for a set of corroded beams, reported in literature, with that predicted using the model proposed in this study indicates that the proposed model has a reasonably good accuracy.

Originality/value

The empirical model obtained under this work can be used as a simple tool to predict residual flexural strength of corroded beams using the input data that include rebar corrosion rate, corrosion duration after initiation and diameter of rebars.

Details

Anti-Corrosion Methods and Materials, vol. 64 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 28 February 2019

Muhd Afiq Hizami Abdullah, Mohd Zulham Affandi Mohd Zahid, Afizah Ayob and Khairunnisa Muhamad

The purpose of this study is to investigate the effect on flexural strength of fire-damaged concrete repaired with high-strength mortar (HSM).

Abstract

Purpose

The purpose of this study is to investigate the effect on flexural strength of fire-damaged concrete repaired with high-strength mortar (HSM).

Design/methodology/approach

Reinforced concrete beams with dimension of 100 mm × 100 mm × 500 mm were used in this study. Beams were then heated to 400°C and overlaid with either HSM or high-strength fiber reinforced mortar (HSFM) to measure the effectiveness of repair material. Repaired beams of different material were then tested for flexural strength. Another group of beams was also repaired and tested by the same procedure but was heated at higher temperature of 600°C.

Findings

Repair of 400°C fire-damaged samples using HSM regained 72 per cent of its original flexural strength, 100.8 per cent of its original toughness and 56.9 per cent of its original elastic stiffness. Repair of 400°C fire-damaged samples using HSFM regained 113.5 per cent of its original flexural strength, 113 per cent of its original toughness and 85.1 per cent of its original elastic stiffness. Repair of 600°C fire-damaged samples using HSM regained 18.7 per cent of its original flexural strength, 25.9 per cent of its original peak load capacity, 26.1 per cent of its original toughness and 22 per cent of its original elastic stiffness. Repair of 600°C fire-damaged samples using HSFM regained 68.4 per cent of its original flexural strength, 96.5 per cent of its original peak load capacity, 71.2 per cent of its original toughness and 52.2 per cent of its original elastic stiffness.

Research limitations/implications

This research is limited to the size of the furnace. The beam specimen is limited to 500 mm of length and overall dimensions. This dimension is not practical in actual structure, hence it may cause exaggeration of deteriorating effect of heating on reinforced concrete beam.

Practical implications

This study may promote more investigation of using HSM as repair material for fire-damaged concrete. This will lead to real-world application and practical solution for fire-damaged structure.

Social implications

The aim of this research in using HSM mostly due to the material’s high workability which will ease its application and promote quality in repair of damaged structure.

Originality/value

There is a dearth of research on using HSM as repair material for fire-damaged concrete. Some research has been carried out using mortar but at lower strength compared to this research.

Details

Journal of Structural Fire Engineering, vol. 10 no. 1
Type: Research Article
ISSN: 2040-2317

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Article
Publication date: 1 July 1995

Y.N. Ziraba, M.H. Baluch, A.M. Sharif, G.J. Al—Sulaimani, A.K. Azad and I.A. Basunbul

This paper presents a finite element model for analysis of damaged RCbeams strengthened or repaired by externally bonding glass fibre reinforcedplastics (GFRP) on the…

Abstract

This paper presents a finite element model for analysis of damaged RC beams strengthened or repaired by externally bonding glass fibre reinforced plastics (GFRP) on the tension side of the beams. The salient features include: (i) the introduction of a thin, six—noded element to simulate behaviour of the concrete/epoxy glue/GFRP interface and )ii( a scheme of loading a virgin RC beam to a prescribed displacement to simulate damage, unloading and then reloading the damaged RC beam fortified by an externally bonded GFRP plate. Results are presented for RC beams repaired by plates of varying thickness and a transmutation of failure mode is noted from classical flexure for the case of external reinforcement in the form of thin GFRP plates to a unique concrete cover rip off failure for thicker GFRP plates and not predicted by the ACI shear strength formula for diagonal tension failure of unplated RC beams of similar geometry.

Details

Engineering Computations, vol. 12 no. 7
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 12 July 2021

Suresh Kumar Arunachalam, Muthukannan Muthiah, Kanniga Devi Rangaswamy, Arunkumar Kadarkarai and Chithambar Ganesh Arunasankar

Demand for Geopolymer concrete (GPC) has increased recently because of its many benefits, including being environmentally sustainable, extremely tolerant to high…

Abstract

Purpose

Demand for Geopolymer concrete (GPC) has increased recently because of its many benefits, including being environmentally sustainable, extremely tolerant to high temperature and chemical attacks in more dangerous environments. Like standard concrete, GPC also has low tensile strength and deformation capacity. This paper aims to analyse the utilization of incinerated bio-medical waste ash (IBWA) combined with ground granulated blast furnace slag (GGBS) in reinforced GPC beams and columns. Medical waste was produced in the health-care industry, specifically in hospitals and diagnostic laboratories. GGBS is a form of industrial waste generated by steel factories. The best option to address global warming is to reduce the consumption of Portland cement production and promote other types of cement that were not a pollutant to the environment. Therefore, the replacement in ordinary Portland cement construction with GPC is a promising way of reducing carbon dioxide emissions. GPC was produced due to an alkali-activated polymeric reaction between alumina-silicate source materials and unreacted aggregates and other materials. Industrial pollutants such as fly ash and slag were used as raw materials.

Design/methodology/approach

Laboratory experiments were performed on three different proportions (reinforced cement concrete [RCC], 100% GGBS as an aluminosilicate source material in reinforced geopolymer concrete [GRGPC] and 30% replacement of IBWA as an aluminosilicate source material for GGBS in reinforced geopolymer concrete [IGRGPC]). The cubes and cylinders for these proportions were tested to find their compressive strength and split tensile strength. In addition, beams (deflection factor, ductility factor, flexural strength, degradation of stiffness and toughness index) and columns (load-carrying ability, stress-strain behaviour and load-deflection behaviours) of reinforced geopolymer concrete (RGPC) were studied.

Findings

As shown by the results, compared to Reinforced Cement Concrete (RCC) and 100% GGBS based Reinforced Geopolymer Concrete (GRGPC), 30% IBWA and 70% GGBS based Reinforced Geopolymer Concrete (IGRGPC) (30% IBWA–70% GGBS reinforced geo-polymer concrete) cubes, cylinders, beams and columns exhibit high compressive strength, tensile strength, flexural strength, load-carrying ability, ultimate strength, stiffness, ductility and deformation capacity.

Originality/value

All the results were based on the experiments done in this research. All the result values obtained in this research are higher than the theoretical values.

Details

World Journal of Engineering, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 25 May 2012

Alan Richardson and Caroline Galloway

This research seeks to investigate the potential of using para‐aramid fibre fabric and yarn as an external reinforcement to existing structures. The purpose of this paper…

Abstract

Purpose

This research seeks to investigate the potential of using para‐aramid fibre fabric and yarn as an external reinforcement to existing structures. The purpose of this paper is to improve existing structural performance or to return the original design performance, during refurbishment. The research aims to investigate the potential for enhanced flexural strength and toughness in concrete beams, which may be required for change of use of buildings, where loadings may be subject to change. Buildings in earthquake zones may also benefit from additional toughness provided with external fabric/yarn reinforcement as a means of providing additional time for escape, for the occupants.

Design/methodology/approach

The test compared four types of concrete beams with different reinforcement material compositions and each set consisted of three beams. The beams were: plain reinforced concrete without any external form of reinforcement (RC), plain unreinforced beams with a para aramid sheet (KF), plain unreinforced beams with para aramid strips of yarn attached longitudinally (KY) and plain reinforced concrete beams with sheet fabric (RCKF). All of the para‐aramid material (fabric and yarn) was externally bonded to the samples, using a two part epoxy resin adhesive applied to a prepared surface. To determine the flexural strength and toughness a three point loading test was used to provide load and deflection data on the 12 (500 mm×100 mm×100 mm) concrete beams.

Findings

An increase in flexural strength and toughness was observed when para‐aramid was used in conjunction with steel reinforcement bar (re‐bar). The para‐aramid fabric and yarn produced similar results to the plain reinforced concrete beam in terms of flexural strength but not toughness.

Originality/value

An advantage of using para‐aramid as an external reinforcement, would be to utilise the large deflection the beam sustains under loading, whilst the fabric/yarn holds the beam together across the rupture plane. Although the testing did not prove that para‐aramid would be a viable alternative to steel re‐bar it did show that the material has the potential as an additional reinforcement that may be particularly useful where concrete structures are subject to large deformations or in need of repair.

Details

Structural Survey, vol. 30 no. 2
Type: Research Article
ISSN: 0263-080X

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