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Article
Publication date: 2 September 2019

Mahfoud Touhari and Ratiba Kettab Mitiche

Covering a fiber-reinforced concrete column (fiber reinforced plastic (FRP)) improves the performance of the column primarily. The purpose of this paper is to investigate the…

Abstract

Purpose

Covering a fiber-reinforced concrete column (fiber reinforced plastic (FRP)) improves the performance of the column primarily. The purpose of this paper is to investigate the behavior of small FRP concrete columns that are subject to axial pressure loading, in order to study the effect of many parameters on the effectiveness of FRP couplings on circular and square concrete columns.

Design/methodology/approach

These parameters include the shape of the browser (circular and square), whole core and cavity, square radius of square columns, concrete strength (low strength, normal and high), type of FRP (carbon and glass) and number of FRP (1–3) layers. The effective fibrillation failure strain was investigated and the effect of effective lateral occlusion pressure.

Findings

The results of the test showed that the FRP-coated columns improved significantly the final conditions of both the circular and square samples compared to the unrestricted columns; however, improvement of square samples was not as prominent as improvement in circular samples. The results indicated that many parameters significantly affected the behavior of FRP-confined columns. A new model for predicting compressive force and the corresponding strain of FRP is presented. A good relationship is obtained between the proposed equations and the current experimental results.

Originality/value

The average hoop strain in FRP wraps at rupture in FRP-confined concrete specimens can be much lower than that given by tensile coupon tests, meaning the theoretical assumption that the FRP-confined concrete cylinder ruptures when the FRP material tensile strength attained at its maximum is not suitable. Based on this observation, the effective peak strength and corresponding strain formula for FRP concrete confined columns must be based on the effective hoop rupture strain composite materials.

Details

International Journal of Structural Integrity, vol. 11 no. 1
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 14 June 2019

Abdurra’uf M. Gora, Jayaprakash Jaganathan, M.P. Anwar and H.Y. Leung

Advanced fibre-reinforced polymer (FRP) composites have been increasingly used over the past two decades for strengthening, upgrading and restoring degraded civil engineering…

Abstract

Purpose

Advanced fibre-reinforced polymer (FRP) composites have been increasingly used over the past two decades for strengthening, upgrading and restoring degraded civil engineering infrastructure. Substantial experimental investigations have been conducted in recent years to understand the compressive behaviour of FRP-confined concrete columns. A considerable number of confinement models to predict the compressive behaviour of FRP-strengthened concrete columns have been developed from the results of these experimental investigations. The purpose of this paper is to present a comprehensive review of experimental investigations and theoretical models of circular and non-circular concrete columns confined with FRP reinforcement.

Design/methodology/approach

The paper reviews previous experimental test results on circular and non-circular concrete columns confined with FRP reinforcement under concentric and eccentric loading conditions and highlights the behaviour and mechanics of FRP confinement in these columns. The paper also reviews existing confinement models for concrete columns confined with FRP composites in both circular and non-circular sections.

Findings

This paper demonstrates that the performance and effectiveness of FRP confinement in concrete columns have been extensively investigated and proven effective in enhancing the structural performance and ductility of strengthened columns. The strength and ductility enhancement depend on the number of FRP layers, concrete compressive strength, corner radius for non-circular columns and intensity of load eccentricity for eccentrically loaded columns. The impact of existing theoretical models and directions for future research are also presented.

Originality/value

Potential researchers will gain insight into existing experimental and theoretical studies and future research directions.

Details

World Journal of Engineering, vol. 16 no. 4
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 9 January 2024

Yunfei Zou

This study aims to enhance the understanding of fiber-reinforced polymer (FRP) applications in partially confined concrete, with a specific focus on improving economic value and…

Abstract

Purpose

This study aims to enhance the understanding of fiber-reinforced polymer (FRP) applications in partially confined concrete, with a specific focus on improving economic value and load-bearing capacity. The research addresses the need for a more comprehensive analysis of non-uniform vertical strain responses and precise stress–strain models for FRP partially confined concrete.

Design/methodology/approach

DIC and strain gauges were employed to gather data during axial compression tests on FRP partially confined concrete specimens. Finite element analysis using ABAQUS was utilized to model partial confinement concrete with various constraint area ratios, ranging from 0 to 1. Experimental findings and simulation results were compared to refine and validate the stress–strain model.

Findings

The experimental results revealed that specimens exhibited strain responses characterized by either hardening or softening in both vertical and horizontal directions. The finite element analysis accurately reflected the relationship between surface constraint forces and axial strains in the x, y and z axes under different constraint area ratios. A proposed stress–strain model demonstrated high predictive accuracy for FRP partially confined concrete columns.

Practical implications

The stress–strain curves of partially confined concrete, based on Teng's foundation model for fully confined stress–strain behavior, exhibit a high level of predictive accuracy. These findings enhance the understanding of the mechanical behavior of partially confined concrete specimens, which is crucial for designing and assessing FRP confined concrete structures.

Originality/value

This research introduces innovative insights into the superior convenience and efficiency of partial wrapping strategies in the rehabilitation of beam-column joints, surpassing traditional full confinement methods. The study contributes methodological innovation by refining stress–strain models specifically for partially confined concrete, addressing the limitations of existing models. The combination of experimental and simulated assessments using DIC and FEM technologies provides robust empirical evidence, advancing the understanding and optimization of FRP-concrete structure performance. This work holds significance for the broader field of concrete structure reinforcement.

Details

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

Keywords

Article
Publication date: 16 August 2019

Virendra Kumar

This paper aims to study the residual test results under uni-axial compression of tie confined pre-damaged normal strength concrete short columns subjected to elevated…

Abstract

Purpose

This paper aims to study the residual test results under uni-axial compression of tie confined pre-damaged normal strength concrete short columns subjected to elevated temperatures.

Design/methodology/approach

The test variables included temperature of exposure, spacing of transverse confining reinforcement and pre-damage level. An experimental program was designed and carried out involving testing of hoop confined concrete cylindrical specimens exposed to elevated temperatures ranging from room temperature to 900 °C.

Findings

The test results indicate that the residual strength, strain corresponding to the peak stress and the post-peak strains of confined concrete are not affected significantly up to an exposure temperature of 300 °C. However, the peak confined stress falls and the corresponding strain increase considerably in the temperature range of 600 to 900 °C. It is shown that an increase in the degree of confinement reinforcement results in an increased residual strength and deformability of pre-damaged confined concrete.

Research limitations/implications

It is applicable in finding the residual strength and strain of the pre-damaged confined concrete in uni-axial compression after exposure to elevated temperature.

Practical implications

The practical implications is that the test result is applicable in finding the residual strengths of pre-damaged confined concrete under uni-axial compression after exposure to elevated temperature.

Social implications

The main aim of the present investigation is to provide experimental data on the residual behaviour of pre-damaged confined concrete subjected to high temperatures.

Originality/value

The results of this study may be useful for developing the guidelines for designing the confinement reinforcement of reinforced concrete columns against the combined actions of earthquake and fire, as well as for designing the retrofitting schemes after these sequential disasters.

Details

Journal of Structural Fire Engineering, vol. 11 no. 1
Type: Research Article
ISSN: 2040-2317

Keywords

Article
Publication date: 27 September 2022

Chafika Ali Ahmed, Abdelmadjid Si Salem, Souad Ait Taleb and Kamal Ait Tahar

This paper aims to investigate the experimental behavior and the reliability of concrete columns repaired using fiber-reinforced polymers (FRPs) under axial compression loading…

Abstract

Purpose

This paper aims to investigate the experimental behavior and the reliability of concrete columns repaired using fiber-reinforced polymers (FRPs) under axial compression loading. The expression of the ultimate axial resistance was assessed from the experimental data of damaged concrete cylinders repaired by externally bonded double-FRP spiral strips.

Design/methodology/approach

The tested columns bearing capacity mainly depends of the elasticity modulus of both damaged and undamaged concrete have been considered in addition to the applied load and the cylinder diameter as random variables in the expression of the failure criterion. The reliability indicators were assessed using first order second moment method.

Findings

The emphasized test results, statistically fitted show that the strength has been retrofitted for all repaired specimens whatever the degree of initial damage. However, the gain in axial strength is inversely proportional to the degree of damage.

Originality/value

The efficiency of a new FRP repair procedure using double-spiral strips was studied. This research provides a technical and economical solution for retrofitting existing concrete columns. Finally, the random character of the variables that govern the studied system shows the accuracy and safety of the proposed original design.

Details

World Journal of Engineering, vol. 21 no. 1
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 7 September 2022

Paulo Silva Lobo, Mariana Jesus and Paulo S.A. Freitas

In this paper a model for the prediction of the failure strain of fiber reinforced polymer (FRP) sheets is proposed, based on a significant database consisting of results reported…

Abstract

Purpose

In this paper a model for the prediction of the failure strain of fiber reinforced polymer (FRP) sheets is proposed, based on a significant database consisting of results reported in the literature for concrete columns with circular cross-section confined with carbon, glass and aramid fiber reinforced polymers. This study aims to analyze the aforementioned model.

Design/methodology/approach

Significant experimental research on the confinement of columns externally wrapped with FRP has been carried out in the last decades. Several models of confined concrete have been proposed using different approaches for the prediction of the failure strain of FRP sheets. The majority of those proposals were developed to be simple, thus significant differences with experimental results can be found.

Findings

The results of a total of 572 specimens were considered. Statistical analysis was used to derive a regression model, which relates the outcome to a set of predictors of interest using linear assumptions.

Originality/value

The proposed model is shown to be more accurate than other proposals found in the literature.

Details

International Journal of Structural Integrity, vol. 14 no. 1
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 7 November 2019

Saranya Ilango and Sunil Mahato

Concrete in-filled stainless steel square tubular column combines both the benefits of concrete and steel material, providing enhanced ductility and high compressive strength to…

Abstract

Purpose

Concrete in-filled stainless steel square tubular column combines both the benefits of concrete and steel material, providing enhanced ductility and high compressive strength to the vertical structural members. Other advantages include high stiffness, better resistance to corrosion, increased pace of construction, enhanced bearing capacity, etc. The purpose of this paper is to understand the various behavioural aspects of concrete in-filled cold-formed duplex stainless steel (CI-CFDSS) square tubular column under axial compressive loads and to assess its structural performance.

Design/methodology/approach

In the current paper, the performance of CI-CFDSS square tubular column is numerically investigated under uniform static loading using finite element technique. The numerical study was based on an experimental investigation, which was carried out earlier, in order to study the effects of concrete strength and shape of stainless steel tube on the strength and behaviour of CI-CFDSS square tubular column. The experimental CI-CFDSS square tubular column has a length equal to 450 mm, breadth of 150 mm, width of 150 mm, thickness of 6 mm and a constant ratio of length to overall depth equal to 3. Numerical modelling of the experimental specimen was carried out using ABAQUS software by providing appropriate material properties. Non-linear finite element analysis was performed and the load vs axial deflection curve of the numerical CI-CFDSS square tubular column obtained was validated with the results of the experiment. In order to understand the behaviour of CI-CFDSS square tubular column under axial compressive loads, a parametric study was performed by varying the grade of concrete, type of stainless steel, thickness of stainless steel tube and shape of cross section. From the results, the performance of CI-CFDSS square tubular column was comparatively studied.

Findings

When the grade of concrete was increased the deformation capacity of the CI-CFDSS square tubular column reduced but showed better load carrying capacity. The steel tube made of duplex stainless steel exhibited enhanced performance in terms of load carrying capacity and axial deformation than the other forms, i.e. austenitic and ferritic stainless steel. The most suitable cross section for the CI-CFDSS square tubular column with respect to its performance is rectangular cross section and variation of the steel tube thickness led to the change of overall dimensions of the N-CI-CFDSS-SHS1C40 square tubular column showing marginal difference in performance.

Originality/value

The research work presented in this manuscript is authentic and could contribute to the understanding of the behavioural aspects of CI-CFDSS square tubular column under axial compressive loads.

Details

International Journal of Structural Integrity, vol. 11 no. 1
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 20 February 2014

Jure Radnic, Radoslav Markic, Alen Harapin, Domagoj Matesan and Goran Baloevic

The results of experimental testing of stirrup effects on compressive strength and ductility of axially loaded confined reinforced concrete columns of rectangular cross-section…

Abstract

The results of experimental testing of stirrup effects on compressive strength and ductility of axially loaded confined reinforced concrete columns of rectangular cross-section are presented. Effects of different concrete strengths, different stirrup bar diameters and different stirrup spacing on column's bearing capacity and ductility have been researched.

Details

World Journal of Engineering, vol. 10 no. 6
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 4 August 2022

Rabab Allouzi, Awni Abu-Shamah and Amer Alkloub

Concrete-filled double-skin tubular (CFDST) columns have been gaining significant attention since these columns proved to be more efficient compared to concrete-filled…

Abstract

Purpose

Concrete-filled double-skin tubular (CFDST) columns have been gaining significant attention since these columns proved to be more efficient compared to concrete-filled steel-tubular (CFST) columns. This paper presents a tool to design slender CFDST columns with/without inclination.

Design/methodology/approach

First, 3D nonlinear finite element (FE) models of twenty-two straight CFDST columns are calibrated and it is found that FE results are in good agreement with the experimental outcomes. This is validated based on available experimental data. Subsequently, a parametric study is conducted by adjusting each calibrated FE model to account for three different angles of inclination. These models are used to quantify the effective length factor of these inclined columns.

Findings

It is found that FE results are in good agreement with the experimental outcomes. An equation is developed in this paper to calculate the characteristic concrete compressive strength for the design of straight CFDST columns. In addition, an equation is presented for engineering practice to calculate the effective length factor at different inclination angles and slenderness ratios to design CFDST columns. The predicted load capacity compares well with the experimental results of straight columns and FE results of inclined columns.

Originality/value

Advancement in the structural design procedure is required as a response to the continuous innovations in architectural design. Designers might introduce an inclination in columns in buildings or bridges, and there are no available guidelines to design them.

Details

Multidiscipline Modeling in Materials and Structures, vol. 18 no. 4
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 16 August 2019

Chang-Shun Hu, Shiping Yin and Meng-Ti Yin

This paper aims to evaluate the bonding properties of textile reinforced concrete (TRC)-confined concrete and corroded plain round bars.

Abstract

Purpose

This paper aims to evaluate the bonding properties of textile reinforced concrete (TRC)-confined concrete and corroded plain round bars.

Design/methodology/approach

The bonding performance of three types of specimens (not reinforced, reinforced after corrosion and reinforced before corrosion) was studied by a central pull out test.

Findings

The ultimate bond strength between the corroded steel bars and the concrete is improved when the corrosion ratio is small. After cracking, the degree of corrosion continues to grow and the ultimate bond strength decreases. TRC reinforcement has no detectable effect on the interfacial bonding properties between concrete and plain round bars when the corrosion of steel bars is small; however, when the concrete cracks under the action of rust corrosion, the TRC constraints can effectively improve the bonding performance of the two components.

Practical implications

TRC layer significantly delayed the chloride penetration rate, which can effectively limit the development of corrosion cracking.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

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