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Article
Publication date: 4 August 2021

Pandimani , Markandeya Raju Ponnada and Yesuratnam Geddada

This study aims to present comprehensive nonlinear material modelling techniques and simulations of reinforced concrete (RC) beams subjected to short-term monotonic static…

Abstract

Purpose

This study aims to present comprehensive nonlinear material modelling techniques and simulations of reinforced concrete (RC) beams subjected to short-term monotonic static load using the robust and reliable general-purpose finite element (FE) software ANSYS. A parametric study is carried out to analyse the flexural and ductility behaviour of RC beams under various influencing parameters.

Design/methodology/approach

To develop and validate the numerical FE models, a total of four experimentally tested simply supported RC beams are taken from the available literature and two beams are selected from each author. The concrete, steel reinforcements, bond-slip mechanism, loading and supporting plates are modelled using SOLID65, LINK180, COMBIN39 and SOLID185 elements, respectively. The validated models are then used to conduct parametric FE analysis to investigate the effect of concrete compressive strength, percentage of tensile reinforcement, compression reinforcement ratio, transverse shear reinforcement, bond-slip mechanism, concrete compressive stress-strain constitutive models, beam symmetry and varying overall depth of beam on the ultimate load-carrying capacity and ductility behaviour of RC beams.

Findings

The developed three-dimensional FE models can able to capture the load and midspan deflections at critical points, the accurate yield point of steel reinforcements, the formation of initial and progressive concrete crack patterns and the complete load-deflection curves of RC beams up to ultimate failure. From the numerical results, it can be concluded that the FE model considering the bond-slip effect with Thorenfeldt’s concrete compressive stress-strain model exhibits a better correlation with the experimental data.

Originality/value

The ultimate load and deflection results of validated FE models show a maximum deviation of less than 10% and 15%, respectively, as compared to the experimental results. The developed model is also capable of capturing concrete failure modes accurately. Overall, the FE analysis results were found quite acceptable and compared well with the experimental data at all loading stages. It is suggested that the proposed FE model is a practical and reliable tool for analyzing the flexural behaviour of RC members and can be used for performing parametric studies.

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: 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…

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

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Article
Publication date: 2 January 2018

Matthew P. Watters and Michelle L. Bernhardt

This paper presents findings from a study examining curing procedures to improve the compressive strength and hardness properties of specimens while maintaining surface…

Abstract

Purpose

This paper presents findings from a study examining curing procedures to improve the compressive strength and hardness properties of specimens while maintaining surface quality. All specimens were created from a standard grey, acrylic-based photopolymer and fabricated using stereolithography technology. This paper aims to investigate the effects of printing layer thickness and print orientation on specimen compressive strength, as well as the effects of thermal and light curing methods. In addition, the post-print curing depth was investigated.

Design/methodology/approach

The effects of layer thickness and print orientation were investigated on 10 × 20 mm cylinders by determining the ultimate compressive strength once cured. The compressive strength of cylinders subjected to varying thermal and light settings was also investigated to determine the optimal curing settings. The effective depth of curing was investigated on a 25.4-mm cuboidal specimen, which received both thermal and light curing.

Findings

To achieve the highest compressive strength, specimens shall be printed with the minimal layer thickness of 25 µm. Increasing temperatures up to 60° C during curing provided a 0.75-MPa increase in compressive strength per degree Celsius. However, increasing temperatures above 60° C only provided a 0.15-MPa increase in compressive strength per degree Celsius. Furthermore, curing temperatures above 110° C resulted in degraded surface quality noted by defects at the layer laminations. Specimens required a minimum light curing exposure time of four hours to reach the maximum cure at which point any increase in exposure time provided no substantial increase in compressive strength.

Originality/value

This study provides recommendations for printing parameters and curing methods to achieve the optimum mechanical properties of cured stereolithography specimens.

Details

Rapid Prototyping Journal, vol. 24 no. 1
Type: Research Article
ISSN: 1355-2546

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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…

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

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Article
Publication date: 30 October 2019

Wang Jiawei and Sun Quansheng

In order to reduce the impact of bridge construction on traffic under the bridge, the construction of bridges for some important traffic nodes usually adopts the swivel…

Abstract

Purpose

In order to reduce the impact of bridge construction on traffic under the bridge, the construction of bridges for some important traffic nodes usually adopts the swivel construction method. The spherical hinge is a rotating mechanism located between the bottom of the pier and the bridge cap, and is subjected to tremendous vertical pressure. According to the mechanical characteristics of the spherical hinges, this paper applies the ultra-high performance concrete (UHPC) material to the spherical hinge. The spherical hinge is subjected to a compression test to test its mechanical behavior. This paper aims to discuss this issue.

Design/methodology/approach

In order to test the mechanical behavior of the UHPC spherical hinge, multiple sets of 100 mm UHPC spherical hinge specimens were prefabricated. Through the universal testing machine to measure the compressive strength of specimens, draw the force-displacement curve to analyze the failure mechanism and establish the stress calculation formula of the spherical hinge at each point along the radial direction.

Findings

Through the test, the compressive strength of UHPC spherical hinge is obtained, and the influencing factors of UHPC spherical hinge strength are found: reducing water–cement ratio, increasing steel fiber content and length and changing steel fiber arrangement direction can effectively improve the compression strength of UHPC spherical hinge.

Originality/value

For the first time, UHPC materials were applied to the spherical hinge structure, the UHPC spherical hinge diameter is 1/3 of the diameter of the reinforced concrete spherical hinge, which is equivalent to the diameter of the steel spherical hinge. By applying the UHPC spherical hinge, the manufacturing cost is reduced, the process is simple, and the construction difficulty is reduced.

Details

International Journal of Structural Integrity, vol. 11 no. 2
Type: Research Article
ISSN: 1757-9864

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Article
Publication date: 19 January 2015

Miguel Castilho, Barbara Gouveia, Inês Pires, Jorge Rodrigues and Manuel Pereira

This paper aims to study the influence of the binder saturation level on the accuracy and on the mechanical properties of three-dimensional (3D)-printed scaffolds for bone…

Abstract

Purpose

This paper aims to study the influence of the binder saturation level on the accuracy and on the mechanical properties of three-dimensional (3D)-printed scaffolds for bone tissue engineering.

Design/methodology/approach

To study the influence of the liquid binder volume on the models accuracy, two quality test plates with different macropore sizes were designed and produced. For the mechanical and physical characterisation, cylindrical specimens were used. The models were printed using a calcium phosphate powder, which was characterised in terms of composition, particle size and morphology, by X-ray diffraction (XRD), laser diffraction and Scanning electron microscopy (SEM) analysis. The sample’s physical characterisation was made using the Archimedes method (porosity), SEM, micro-computer tomography (CT) and digital scan techniques, while the mechanical characterisation was performed by means of uniaxial compressive tests. Strength distribution was analysed using a statistical Weibull approach, and the dependence of the compressive strength on the porosity was discussed.

Findings

The saturation level is determinant for the structural characteristics, accuracy and strength the models produced by three-dimensional printing (3DP). Samples printed with the highest saturation showed higher compressive strengths (24 MPa), which are over the human trabecular bone. The models printed with lower saturations presented the highest accuracy and pore interconnectivity.

Originality/value

This study allowed to acquire important knowledge concerning the effects of shell/core saturation on the overall performance of the 3DP. With this information it is possible to devise scaffolds with the required properties for bone scaffold engineering.

Details

Rapid Prototyping Journal, vol. 21 no. 1
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 30 April 2020

Saleh Ahmed Aldahash and Abdelrasoul M. Gadelmoula

The cement-filled PA12 manufactured by selective laser sintering (SLS) offers desirable mechanical properties; however, these properties are dependent on several…

Abstract

Purpose

The cement-filled PA12 manufactured by selective laser sintering (SLS) offers desirable mechanical properties; however, these properties are dependent on several fabrication parameters. As a result, SLS prototypes may exhibit orthotropic mechanical properties unless properly oriented in build chamber. This paper aims to evaluate the effects of part build orientation, laser energy and cement content on mechanical properties of cement-filled PA12.

Design/methodology/approach

The test specimens were fabricated by SLS using the “DTM Sinterstation 2000” system at which the specimens were aligned along six different orientations. The scanning speed was 914mm/s, scan spacing was 0.15mm, layer thickness was 0.1mm and laser power was 4.5–8Watt. A total of 270 tensile specimens, 270 flexural specimens and 135 compression specimens were manufactured and the tensile, compression and flexural properties of fabricated specimens were evaluated.

Findings

The experiments revealed orientation-dependent (orthotropic) mechanical properties of SLS cement-filled PA12 and confirmed that the parts with shorter scan vectors have enhanced flexural strength as compared with longer scan vectors. The maximum deviations of ultimate tensile strength, compressive strength and flexural modulus along the six orientations were 32%, 26% and 36%, respectively.

Originality/value

Although part build orientation is a key fabrication parameter, very little was found in open literature with contradictory findings about its effect on mechanical properties of fabricated parts. In this work, the effects of build orientation when combined with other fabrication parameters on the properties of SLS parts were evaluated along six different orientations.

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Article
Publication date: 2 September 2019

Faezeh Nejati and S.A. Edalatpanah

The purpose of this paper is to investigate the effect of steel and carbon fibers on the mechanical properties of light concrete in terms of tension strength, compressive

Abstract

Purpose

The purpose of this paper is to investigate the effect of steel and carbon fibers on the mechanical properties of light concrete in terms of tension strength, compressive strength and elastic modulus under completely dry and wet conditions.

Design/methodology/approach

In this study, the lightweight concrete made of Light Expanded Clay Aggregate (LECA) as coarse aggregate and sand as fine aggregate was used. To achieve a compressive strength of at least 20 MPa, microsilica was used 10 percent by weight of cement. In order to compensate for the reduction of tension strength of concrete, steel and carbon fibers were used with three volume ratio of 0.5, 1 and 1.5 percent in concrete. The results of concrete specimens were studied at the age of 7, 28, 42 and 90 days under controlled dry and wet conditions.

Findings

The results showed that the addition of steel and carbon fibers to the concrete mixture would reduce the drop in slump. Also, the use of steel and carbon fibers plays a significant role in increasing the tension strength of the specimens. Furthermore, the highest increase in tension strength of steel and carbon fiber samples was 83.3 and 50 percent, respectively, than the non-fibrous specimen when evaluated at 90 days of age. Moreover, the steel and carbon fiber increased the water absorption of the samples. Adding steel and carbon fibers to a lightweight concretes mixture containing LECA aggregates plays a significant role in increasing the modulus of elasticity of the samples. The highest increase in the elastic modulus of steel and carbon fibers was 18.9 and 35.4 percent, respectively, than the non-fibrous specimen at 28 days of age.

Originality/value

In this paper, the authors investigated the mechanical properties of steel fiber and carbon reinforced concrete. Also, according to the conditions of storage of samples and the age of concrete (day), the experiments were carried out on samples.

Details

International Journal of Structural Integrity, vol. 11 no. 2
Type: Research Article
ISSN: 1757-9864

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Article
Publication date: 4 August 2017

Vadims Goremikins, Lukas Blesak, Josef Novak and Frantisek Wald

This work aims to present an experimental study of steel fibre-reinforced concrete (SFRC) subjected to high temperature, especially focusing on residual behaviour.

Abstract

Purpose

This work aims to present an experimental study of steel fibre-reinforced concrete (SFRC) subjected to high temperature, especially focusing on residual behaviour.

Design/methodology/approach

Compressive strength and split tensile strength of SFRC cubes and ultimate bending strength of prisms were evaluated under ambient and elevated temperatures. The specimens were heated by ceramic heaters and then repacked for testing.

Findings

The results showed that a compressive strength of SFRC is reduced by 38 and 66 per cent, tensile strength is reduced by 25 and 59 per cent and ultimate bending force is reduced by 33 and 56 per cent in case of 400°C and 600°C, respectively, comparing with ambient temperature.

Originality value

The developed testing procedure could be used for determination of material properties of SFRC under elevated temperatures.

Details

Journal of Structural Fire Engineering, vol. 8 no. 3
Type: Research Article
ISSN: 2040-2317

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Article
Publication date: 21 June 2013

Osama Bedair

The paper aims to review recent developments for analysis of deteriorating stiffened panels subjected to static and explosive forces.

Abstract

Purpose

The paper aims to review recent developments for analysis of deteriorating stiffened panels subjected to static and explosive forces.

Design/methodology/approach

The first part reviews numerical procedures developed for stiffened panels subjected to explosive forces. The structural idealization, the theoretical basis, and the merits of these methods are discussed. The second part reviews the probabilistic procedures developed for analysis of deteriorating stiffened panels. The third part reviews recent work developed in several finite element modelling philosophies for analysis of stiffened panels. The influence of various parameters affecting the structural performance, such as geometric and material imperfections, corrosion, residual stresses, etc. is discussed. The fourth part reviews hybrid procedures developed to provide approximate solutions for the designers. Numerical procedure is presented using combination of energy formulations and mathematical programming techniques to model the interaction between the box girder components.

Findings

Localized damage largely affects the performance of stiffened panels and must be accounted for in the design phase. Little emphasis was given in the published literature to developing simplified analytical models that can be used in practice to compute the residual strength of the stiffened panels under these types of loadings. Furthermore, analytical expressions are required to compute the reduction in the stiffness induced due to the structural or material defects. These expressions must be dependent on the type of damage. It must be noted that some of this damages is localized in nature and must be accounted for by using specialized functions to assess the structural defect accurately. Research work is required in this direction.

Practical implications

The paper provides useful resource material for the engineers in practice regarding recent techniques developed to assess damaged stiffened panels subject to static and explosive loadings. The paper reviews work developed over the past 20 years that can be used as a baseline for future developments.

Originality/value

Very limited literature dealt with the ultimate strength of damaged stiffened structure under static and explosive forces. No guidelines are available in current design codes to assess the damage in predicting the strength of deteriorating stiffened panels.

Details

Multidiscipline Modeling in Materials and Structures, vol. 9 no. 1
Type: Research Article
ISSN: 1573-6105

Keywords

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