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Article
Publication date: 9 June 2022

Jinliang Liu and Fangpu Yan

A numerical simulation of the test beam was carried out with Abaqus and compared with test data to ensure that the modeling method is accurate. An analysis of the effects…

Abstract

Purpose

A numerical simulation of the test beam was carried out with Abaqus and compared with test data to ensure that the modeling method is accurate. An analysis of the effects of the angle between the U-hoop and horizontal direction, the pre-crack height, the pre-crack spacing, and the strength of the geopolymer adhesive on the cracking load and ultimate load of the reinforced beam is presented.

Design/methodology/approach

Load tests and finite element simulations were conducted on carbon fiber reinforced polymer-reinforced concrete beams bonded with geopolymer adhesive. The bond-slip effect of geopolymer adhesive was taken into account in the model. The flexural performances, the flexural load capacities, the deformation capacities, and the damage characteristics of the beams were observed, and the numerical simulation results were in good agreement with the experimental results. An analysis of parametric sensitivity was performed using finite element simulation to investigate the effects of different angles between U-hoop and horizontal direction, pre-crack heights, pre-crack spacing, and strength of geopolymer adhesive on cracking load and ultimate load.

Findings

Under the same conditions, the higher the height of the pre-crack, the lower the bearing capacity; increasing the pre-crack spacing can delay cracking, but reduce ultimate load. By increasing the strength of the geopolymer adhesive, the flexural resistance of the beam is improved, and crack development is also delayed; the angle between the u-hoop and horizontal direction does not affect the cracking of reinforced beams; a horizontal u-hoop has a better effect than an oblique u-hoop, and 60° is the ideal angle between the u-hoop and horizontal direction for better reinforcement.

Originality/value

According to the experimental study in this paper, Abaqus was used to simulate the strength of different angles between U-hoop and horizontal direction, pre-crack heights, pre-crack spacings, and geopolymer adhesives, and the angles' effects on the cracking load and load carrying capacity of test beams were discussed. Since no actual tests are required, the method is economical. This paper offers data support for the promotion and application of environmentally friendly reinforcement technology, contributes to environmental protection, and develops a new method for reinforcing reinforced concrete beams and a new concept for finite element simulations.

Details

Multidiscipline Modeling in Materials and Structures, vol. 18 no. 3
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 22 August 2022

Long Liu and Songqiang Wan

To make full use of the tensile strength of near surface mounting (NSM) pasted carbon fiber reinforced plastics (CFRP) strips and further increase the flexural bearing…

18

Abstract

Purpose

To make full use of the tensile strength of near surface mounting (NSM) pasted carbon fiber reinforced plastics (CFRP) strips and further increase the flexural bearing capacity and flexibility of reinforced concrete (RC) beams, a new composite reinforcement method using ultra-high performance concrete (UHPC) layer in the compression zone of RC beams is submitted based on embedding CFRP strips in the tension zone of RC beams. This paper aims to discuss the aforementioned points.

Design/methodology/approach

The experimental beam was simulated by ABAQUS, and compared with the experimental results, the validity of the finite element model was verified. On this basis, the reinforced RC beam is used as the control beam, and parameters such as the CFRP strip number, UHPC layer thickness, steel bar ratio and concrete strength are studied through the verified model. In addition, the numerical calculation results of yield strength, ultimate strength, failure deflection and flexibility are also given.

Findings

The flexural bearing capacity of RC beams supported by the new method is 132.3% higher than that of unreinforced beams, and 7.8% higher than that of RC beams supported only with CFRP strips. The deflection flexibility coefficient of the new reinforced RC beam is 8.06, which is higher than that of the unreinforced beam and the reinforced concrete beam with only CFRP strips embedded in the tension zone.

Originality/value

In this paper, a new reinforcement method is submitted, and the effects of various parameters on the ultimate bearing capacity and flexibility of reinforced RC beams are analyzed by the finite element numerical simulation. Finally, the effectiveness of the new method is verified by the analytical formula.

Details

International Journal of Building Pathology and Adaptation, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2398-4708

Keywords

Article
Publication date: 30 March 2022

Jinliang Liu and Fangpu Yan

In this paper, the effects of geopolymer adhesive, the number of CFRP layers and the width of pre-crack on the flexural performance of reinforced concrete beams…

Abstract

Purpose

In this paper, the effects of geopolymer adhesive, the number of CFRP layers and the width of pre-crack on the flexural performance of reinforced concrete beams strengthened with CFRP were studied, and the flexural capacity of strengthened beams was calculated theoretically.

Design/methodology/approach

Reinforced concrete beams were strengthened with CFRP by geopolymer adhesive, and flexural load tests were conducted to observe the reinforcement effect. Based on the method of calculating the flexural capacity of reinforced concrete beams, a theoretical calculation model on the flexural capacity of reinforced concrete beams strengthened with geopolymer adhesive bonded CFRP was established.

Findings

The test data shown the flexural capacity of epoxy resin adhesive CFRP strengthened reinforced concrete beams is 7.76% higher than that geopolymer adhesive is used. The flexural capacity of reinforced concrete beams strengthened with three layers of CFRP is 1.86% higher than that two layers are adopted. The mean ratio of the test data and the calculation results of the flexural capacity is 0.973, and the mean square error is 0.008. It can be seen that the test data are in good agreement with the theoretical value.

Originality/value

This paper provides data support for the popularization and application of the new environment-friendly reinforcement technology, contributes to the cause of environmental protection, and provides a new method for strengthening reinforced concrete beams.

Details

International Journal of Structural Integrity, vol. 13 no. 3
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 31 August 2022

Aya Qatawna, Rabab Allouzi and Samih Qaqish

The primary objective of this study is to produce one-way slabs made of LWFC with low density and sufficient compressive strength suitable for structural purpose then…

Abstract

Purpose

The primary objective of this study is to produce one-way slabs made of LWFC with low density and sufficient compressive strength suitable for structural purpose then investigate their flexural behavior under various types of reinforcement and thickness of the slab and the influence of addition of PP fibers reinforcement on the mechanical behavior of reinforced concrete slabs. The specimens were tested using four-point loading. The results concerning load capacity, deflection and failure mode and crack pattern for each specimen were obtained. Also, an analytical investigation of PP fiber and GFG contribution on the flexural behavior of foamed concrete slabs is studied to investigate the significant role of PP fiber on the stress distribution in reinforced foam concrete and predict the flexural moment capacity.

Design/methodology/approach

The materials used in this study are cement, fine aggregate (sand), water, PP fibers, foaming agent, chemical additives if required, steel reinforcing rebars and glass fiber grid. The combination of these constituent materials will be used to produce foamed concrete in this research Then this study will present the experimental program of one-way foamed concrete slabs including slabs reinforced with GFR grids and another with steel reinforcements. The slabs will be tested in the laboratory under static loading conditions to investigate their ultimate capacities. The flexural behavior is to the interest of the slabs reinforced with GFR grids reinforcements in comparison with that of one with steel reinforcing rebars. Three groups are considered. (1) Group I: two slabs of PP fiber foamed concrete with minimum required reinforcements. (2) Group II: two slabs of PP fiber foamed concrete with glass fiber grids. (3) Group III: two slabs of PP fiber foamed concrete with the minimum required reinforcements and glass fiber grids.

Findings

The experimental results proved the effectiveness and efficiency of this the new system in producing a low density of concrete below 1900 kg/m3 had a corresponding strength of about 17 MPa at least. Besides, the presence of PP fibers had a noticeable improvement on the flexural strength values for all the examined slabs. It was found that the specimens reinforced with steel reinforcement mesh carried higher flexural capacity compared to these reinforced with GFG only. The specimens reinforced with GFG exhibited the lowest flexural capacity due to GFG separation from the concrete substrate. Also, an analytical investigation to predict the flexural strength of all tested specimens was carried out. The analytical results were agreed with the experimental results. Therefore, LWFC can be used as a substitute lightweight concrete material for the production of structural concrete applications in the construction industries today.

Research limitations/implications

Foamed concrete is a wide field to discuss. To achieve the objectives of the project, the study is focused on the foamed concrete with the following limitations: (1) because the aim of this research is to produce foamed concrete suitable for structural purposes, it is decided to produce mixes within the density range 1300–1900 kg/m3. (2) Simply-supported slabs are of considered. (3) This study also looks out by using GFR and without it.

Originality/value

The main objectives of this study were producing structural foamed concrete slabs and investigate their flexural response for residential uses.

Details

International Journal of Building Pathology and Adaptation, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2398-4708

Keywords

Article
Publication date: 1 May 2002

R.V. Balendran, T.M. Rana, T. Maqsood and W.C. Tang

This paper presents an overview and discusses the applications of fibre reinforced polymer (FRP) bars as reinforcement in civil engineering structures. Following a…

3700

Abstract

This paper presents an overview and discusses the applications of fibre reinforced polymer (FRP) bars as reinforcement in civil engineering structures. Following a discussion of the science underpinning their use, selected case studies where FRP reinforcement has been used are presented. The use of FRP reinforcement is rapidly gaining pace and may replace the traditional steel due to its enhanced properties and cost‐effectiveness. In addition, FRP reinforcement offers an effective solution to the problem of steel durability in aggressive environments and where the magnetic or electrical properties of steel are undesirable.

Details

Structural Survey, vol. 20 no. 2
Type: Research Article
ISSN: 0263-080X

Keywords

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.

Details

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

Keywords

Article
Publication date: 16 December 2021

Bashar Ramzi Behnam and Mohammed M. Mahmood Al-Iessa

The purpose of this paper is to investigate the potential design advantage in terms of resistance factors for normal weight concrete beams containing moderate-dose…

Abstract

Purpose

The purpose of this paper is to investigate the potential design advantage in terms of resistance factors for normal weight concrete beams containing moderate-dose randomly dispersed short fibers and reinforced with glass fiber reinforced polymer (GFRP) bars.

Design/methodology/approach

An analytical model based on the current code specifications is used to calculate the moment capacity of over-reinforced sections. The vast majority of the considered beams are over-reinforced, compression-controlled. The data of the fiber-reinforced concrete (FRC) reinforced with GFRP bars are collected from three published research studies which are based on experimentally tested results. Three different types of short fibers with four volume fractions are considered. Probabilistic model is established to conduct reliability-based calibration using Monte-Carlo Simulation. Limit state function, relevant load and resistance random variables are identified, and adequate statistical parameters are selected. Target reliability index consistent with the one used to develop current design code specifications is used.

Findings

Reliability analysis and calibration process are carried out with the intention of estimating the flexural resistance factors for FRC beams reinforced with GFRP bars.

Originality/value

The predicted flexural resistance factors ranged from 0.72 to 0.95, giving the resistance factors the potential to be increased above the currently specified value of 0.65 for compression-controlled members reinforced with FRP bars.

Details

International Journal of Structural Integrity, vol. 13 no. 2
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 1 January 1993

ADNAN IBRAHIMBEGOVIĆ and FRANÇOIS FREY

An efficient implementation of a constitutive model for reinforced concrete plates is discussed in this work. The constitutive model is set directly in terms of stress…

Abstract

An efficient implementation of a constitutive model for reinforced concrete plates is discussed in this work. The constitutive model is set directly in terms of stress resultants and their energy conjugate strain measures, relating their total values. The latter simplification is justified by our primary goal being an evaluation of the limit load of a reinforced concrete plate. A concept of the ‘rotating crack model’ is utilized in proposing the constitutive model to relate the principal values of bending moments and the corresponding values of curvatures. Efficient implementation is provided by a very robust, but inexpensive plate element. The element is based on an assumed shear strain field and a set of incompatible bending modes, which provides that the non‐linear computations, pertinent to constitutive model, can be carried out locally, i.e. independently at each numerical integration point. Set of numerical examples is presented to demonstrate a very satisfying performance of the proposed model.

Details

Engineering Computations, vol. 10 no. 1
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 July 2005

Pavao Marović, Željana Nikolić and Mirela Galić

To provide an insight in one relatively simple and efficient numerical model for analysing reinforced and prestressed concrete structures, and to raise a discussion…

Abstract

Purpose

To provide an insight in one relatively simple and efficient numerical model for analysing reinforced and prestressed concrete structures, and to raise a discussion leading to the creation of one universal and robust 3D algorithm.

Design/methodology/approach

A new numerical model for analysing reinforced and prestressed concrete structures is developed and main theoretical details are described to aid the understandings. The approach is clear, easily readable and the body of the text is divided into logical sections starting from theoretical explanations ending in the large number of different practical examples.

Findings

Provides information about developing new and relatively simple numerical model for analysing reinforced and prestressed concrete structures, indicating what can be improved. Recognises the lack of knowing real behaviour of 3D concrete and starts a discussion on it.

Research limitations/implications

The knowledge of the 2D and especially 3D concrete behaviour is still poor and the concrete model developers use many simplifications. So, many new experiments should be performed and better numerical models should be developed. There is large area for researchers but having in mind that experiments are very expensive.

Practical implications

Obtained results of the 3D analysis of reinforced and prestressed concrete structures can stand as a benchmark for future researches in this field especially to the young researchers and concrete model developers.

Originality/value

This paper presents new and very simple numerical model for analysing reinforced and prestressed concrete structures. Paper could be very valuable to the researchers in this field as a benchmark for their analyses.

Details

Engineering Computations, vol. 22 no. 5/6
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 7 October 2013

Nikolina Zivaljic, Hrvoje Smoljanovic and Zeljana Nikolic

The purpose of this paper is to present a new numerical model based on a combined finite-discrete element method, capable of predicting the behaviour of reinforced concrete

Abstract

Purpose

The purpose of this paper is to present a new numerical model based on a combined finite-discrete element method, capable of predicting the behaviour of reinforced concrete structures under dynamic load up to failure.

Design/methodology/approach

An embedded model of reinforcing bars is implemented in combined finite-discrete element code. Cracking of the structure was enabled by a combined single and smeared crack model. The model for reinforcing bars was based on an approximation of the experimental curves for the bar strain in the crack. The developed numerical model includes interaction effects between reinforcement and concrete and cyclic behaviour of concrete and steel during dynamic loading.

Findings

The findings provide a realistic description of cracking in the concrete structure, where all non-linear effects are realized in joint elements of the concrete and reinforcing bars. This leads to a robust and precise model for non-linear analysis of reinforced concrete structures under dynamic load.

Originality/value

This paper presents new robust finite-discrete element numerical model for analysis and prediction of the collapse of reinforced concrete structures. The model is capable of including the effects of dynamic loading on the structures, both in the linear-elastic range, as well as in the non-linear range including crack initiation and propagation, energy dissipation due to non-linear effects, inertial effects due to motion, contact impact, and the state of rest, which is a consequence of energy dissipation in the system.

Details

Engineering Computations, vol. 30 no. 7
Type: Research Article
ISSN: 0264-4401

Keywords

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