Fibre-reinforced polymer (FRP) is a type of composite material used to provide resistance to corr... more Fibre-reinforced polymer (FRP) is a type of composite material used to provide resistance to corrosion when incorporated into piles. However, there is a gap in knowledge in terms of the behaviour of FRP piles under axial or lateral loading in soils. Thus, the aim of this experimental study is to assess the factors that influence the behaviour of FRPs under axial and lateral load in sandy soil. CFRP (carbon-fibre-reinforced polymer) and GFRP (glass-fibre-reinforced polymer) piles were tested in this experiment based on a special pressure chamber. The results show that the surface roughness (Rt), confined pressure (σc), and relative density (Dr) determined the shearing resistance of the soils and subsequently affected the bearing capacity of the FRP piles under an axial load. The flexural stiffness of the FRP piles was determined by the FRP type, pile dimeter, and aging in the environment, which were affected under the lateral load. In addition, an alkaline environment was more aggres...
The aim of this study was to provide a general conceptual understanding of the effect of hardness... more The aim of this study was to provide a general conceptual understanding of the effect of hardness and roughness of a continuum surface on its interface shear behavior against granular materials. A carefully designed experimental program was conducted to investigate this issue. The results were utilized to define schematically the general geometric configurations of the constitutive interface shear surface (CISS) in the three-dimensional domain of surface roughness, surface hardness, and interface shear coefficient. The proposed CISS provides a robust mean to understand the coupling effect of continuum surface roughness and hardness on the interface shear behaviour.
Oil pollution of the soil due to a leakage in oil tubes, transportation of products, or during oi... more Oil pollution of the soil due to a leakage in oil tubes, transportation of products, or during oil excavations can change the soil physical and mechanical, chemical, and biological properties. Consequently, the soil may or may not be eligible for engineering construction projects and it may need a significant treatment. Therefore, it is required to have a better understanding of the general behavior and the corresponding geotechnical properties upon pollution particularly for those areas associated with oil explorations and industry like Thi-Qar Governorate. Fine and coarse soils from two sites at the University of Thi-Qar are artificially contaminated with oil products ranging from 0% to 10% of their dry weight. Testing programs have been performed on both soils included conventional tests such as grading, Atterberg limit, vane shear and direct shear tests. To achieve a fair comparison, the outcomes are directly compared to those of the original uncontaminated soil. The final results of this study indicated the variations in the soil properties for the studied soils upon contamination and addressed the concept behind such behavior.
The surface topography of fibre-reinforced polymer (FRP) tube confined concrete piles may be sign... more The surface topography of fibre-reinforced polymer (FRP) tube confined concrete piles may be significantly altered during the driving installation process. This change could affect the interface pile design parameters and therefore an accurate quantification of this change is required to precisely determine the pile shaft resistance. This article presents the results of an experimental study carried out to investigate the changes in surface topography and interface shear coefficient of two different FRP counterface surfaces that sheared against different types of sand under increased normal stress levels. The test results indicate that quantifiable surface topography changes could be induced by subjecting FRP surfaces to interface shearing under increased normal stress levels. Furthermore, the interface shear resistance coefficient decreases as the normal stress increases. The study also shows that the deterioration of the interface shear resistance coefficient as the normal stress ...
Mathematical Modelling of Engineering Problems, 2021
The term "reinforced soil" refers to a composite material with high tensile-strength co... more The term "reinforced soil" refers to a composite material with high tensile-strength components that enhance the soil's tensile strength. One of the most common kinds of geosynthetic fabric utilized for soil reinforcement is geotextiles. This article investigates woven geotextile's potential benefits in enhancing the maximum load-carrying capacity of footings resting upon silty sand soil. The foundation was constructed of a 10 mm thick strong carbon steel plate of 100 mm×100 mm. The factors examined in this research were the first geotextile layer's depth, the geotextile layer's width, the number of layers of reinforcing material, and the vertical spacing between geotextile layers. The impact of geotextile strengthening configurations on the load-carrying capacity of strengthened soil foundations was also studied. The results of the experiments indicated that geotextile reinforced soil could help to grow the soil bearing capacity. The testing findings revea...
Lowland technology international : the official journal of the International Association of Lowland Technology, 2014
Several studies in the literature have investigated the shear behaviour of soil-steel interface. ... more Several studies in the literature have investigated the shear behaviour of soil-steel interface. Furthermore, a normalized relative roughness parameter, R n , has been used successfully to describe the shear behaviour of the sandsteel interface. On the other hand, few studies are available in the literature regarding the interface shear behaviour of fiber reinforced polymer (FRP). The aim of this study is to investigate the shear behaviour of soil-FRP interface and examine the validity of R n for the FRP case. Experimental program using a modified direct shear test apparatus was conducted for this purpose. The testing materials in this study include two different types of FRP, and five different-size glass beads in terms of the mean particle size, D 50. The experimental results show that the interface shear behaviour of FRP is different than steel. The observed difference could be explained in terms of the expected contribution of the interface ploughing resistance in the FRP case compared to the steel where its interface shear behaviour is mainly controlled by the interface sliding resistance.
The improvement of sub-grade has always been significant aspect in highway and geotechnical engin... more The improvement of sub-grade has always been significant aspect in highway and geotechnical engineering fields. To strengthen the subgrade soil, the use of natural Jute fiber is advantageous because they are cheap, locally available, and biodegradable. In this paper the soil sample was compacted at its maximum dry density corresponding to its optimum moisture content in the Laboratory California Bearing Ratio (CBR) mould with and without natural Jute fiber. Natural Jute fiber sheets equal to the plan of CBR mould diameter were placed at various layers (second, fourth and fifth of soil's layers) to investigate its behaviour on CBR value. The experimental investigations were also involved natural Jute fiber coated with bitumen material to study the effect of bitumen material on the CBR value. The CBR values of soil and soil reinforced with Jute fiber were investigated in the geotechnical engineering laboratory. The results of experimental investigation showed that the inclusion of...
The geophysical testing is increasingly being employed in many geotechnical applications. It is p... more The geophysical testing is increasingly being employed in many geotechnical applications. It is preferred in monitoring the mechanical characteristics of the ground because of its economy, not time consuming and non-destructive nature. Seismic wave test is one of the geophysical methods which showed a potential in observing the general behaviour of the reinforced soil with stone columns. Findings in most cases showed that the seismic wave measurements was integrated with or compared to the conventional tests such as standard penetration test or cone penetration test. There was a noticeable success in identifying the enhancement achieved to the ground upon the strengthening with the column, specifically when the associated surveys can produce a clear image of the underground which interprets the variation in the soil properties not prior to the soil treatment only, but even after the treatment occurring. However, from practical point of view, there were still some restrictions with...
Fibre reinforced polymer (FRP) composites represent an alternative construction material for deep... more Fibre reinforced polymer (FRP) composites represent an alternative construction material for deep foundations that have the potential to eliminate most of the durability concerns associated with traditional piling materials. Research studies and database related to the use FRP composite material as piling foundation is very limited. This research project was undertaken to investigate the structural and geotechnical behaviour of FRP composite piles. The originality of this study rests on the following pillars:? Presenting a new understanding for the factors controlling the compressive strength of FRP tube confined concrete. ? Introducing the concept of constitutive interface surface which considers the effect of surface hardness and relative roughness on the interface shear coefficient. ? Studying the evolution of FRP pile surface roughness during the driving process. ? Investigating the effect of harsh environments on the shear behaviour of FRP-granular interface. ? Conducting an ex...
Abstract The application of FRP-confined concrete is recognized to be an effective solution to in... more Abstract The application of FRP-confined concrete is recognized to be an effective solution to increase the axial strength of many new and existing concrete columns. A number of experimental investigations and developments for numerical models have been established to understand the strength enhancement behaviour of the FRP-concrete confined section. This paper aims to investigate the influence of the confinement parameters including the concrete strength and the confining pressure on the strength enhancement of FRP-confined concrete specimens. Investigated data were collected from experimental works performed by the authors as well as results surveyed from state-of-the-art papers carefully selected and reviewed to provide an overview and in-depth knowledge in the development of this strengthening technique. Utilizing 927 experimental data from 127 papers from the literature, a 3-dimensional graph presentation (surface chart) have been utilized to investigate the strength enhancement of the FRP-confined concrete. This new graphing format assisted in demonstrating the non-linear influences for each of the parameters investigated on the confinement parameters on the strength enhancement of FRP-confined section. Unlike the conventional 2-dimensional plot of the confined concrete strength versus the confining pressure (both normalized by the unconfined concrete strength), the 3-dimensional graphing approach introduced in this paper is found to provide more information about the strength enhancement. Utilizing a Gauss surface fitting function, a refined enhancement ratio expression incorporating the individual influence of the confinement parameters is proposed in the paper and experimentally evaluated.
High-performance concrete mixes containing various proportions of natural pozzolan and silica fum... more High-performance concrete mixes containing various proportions of natural pozzolan and silica fume (up to 15% by weight of cement) were prepared and stored in sodium and magnesium sulfate solutions, in Dead Sea and Red Sea waters. The progressive deterioration and the relative sulfate resistance of these mixes were evaluated through visual observations, ultrasonic pulse velocity measurements, and relative strength determinations. The investigation indicated that the concrete mix containing 15% natural pozzolan, and 15% silica fume showed the best protection in sulfates solutions and sea waters. It retained more than 65% of its strength after one year of storage in sulfates solutions and sea waters. The superior resistance of that mix against sulfate attack is attributed to the pore refinement process and further densification of the transition zone occurring due to the conversion of lime forming from the hydration of cement into additional binding material through lime-pozzolan reaction. This investigation recommends the use of silica fume in combination with natural pozzolan for better performance in severe sulfate environments.
Pile foundations are commonly used to resist vertical and lateral loads applied to structures. Us... more Pile foundations are commonly used to resist vertical and lateral loads applied to structures. Usually, these kinds of loads will act together to form a combination of loads, such as oblique forces that have a component of vertical and lateral forc- es. Predicting the behavior of piles subjected to oblique loads still remains a challenging task to geotechnical engineers. In this paper, results of numerical simulation of behavior of piles as embedded in cohesionless soil under oblique loads are presented by using ABAQUS. For the cohesionless soil, the Mohr-Coloumb constitutive law has been used to simulate the surrounding soil while the linear elastic model is used for modeling of the pile. The interactions between the pile and the surrounding soil are modeled thoroughly using contact elements based on slave-master concept. The results are shown in terms of load/displacement curves for the components of vertical and the lateral loading portions in different inclination angles. Finall...
Fibre-reinforced polymer (FRP) is a type of composite material used to provide resistance to corr... more Fibre-reinforced polymer (FRP) is a type of composite material used to provide resistance to corrosion when incorporated into piles. However, there is a gap in knowledge in terms of the behaviour of FRP piles under axial or lateral loading in soils. Thus, the aim of this experimental study is to assess the factors that influence the behaviour of FRPs under axial and lateral load in sandy soil. CFRP (carbon-fibre-reinforced polymer) and GFRP (glass-fibre-reinforced polymer) piles were tested in this experiment based on a special pressure chamber. The results show that the surface roughness (Rt), confined pressure (σc), and relative density (Dr) determined the shearing resistance of the soils and subsequently affected the bearing capacity of the FRP piles under an axial load. The flexural stiffness of the FRP piles was determined by the FRP type, pile dimeter, and aging in the environment, which were affected under the lateral load. In addition, an alkaline environment was more aggres...
The aim of this study was to provide a general conceptual understanding of the effect of hardness... more The aim of this study was to provide a general conceptual understanding of the effect of hardness and roughness of a continuum surface on its interface shear behavior against granular materials. A carefully designed experimental program was conducted to investigate this issue. The results were utilized to define schematically the general geometric configurations of the constitutive interface shear surface (CISS) in the three-dimensional domain of surface roughness, surface hardness, and interface shear coefficient. The proposed CISS provides a robust mean to understand the coupling effect of continuum surface roughness and hardness on the interface shear behaviour.
Oil pollution of the soil due to a leakage in oil tubes, transportation of products, or during oi... more Oil pollution of the soil due to a leakage in oil tubes, transportation of products, or during oil excavations can change the soil physical and mechanical, chemical, and biological properties. Consequently, the soil may or may not be eligible for engineering construction projects and it may need a significant treatment. Therefore, it is required to have a better understanding of the general behavior and the corresponding geotechnical properties upon pollution particularly for those areas associated with oil explorations and industry like Thi-Qar Governorate. Fine and coarse soils from two sites at the University of Thi-Qar are artificially contaminated with oil products ranging from 0% to 10% of their dry weight. Testing programs have been performed on both soils included conventional tests such as grading, Atterberg limit, vane shear and direct shear tests. To achieve a fair comparison, the outcomes are directly compared to those of the original uncontaminated soil. The final results of this study indicated the variations in the soil properties for the studied soils upon contamination and addressed the concept behind such behavior.
The surface topography of fibre-reinforced polymer (FRP) tube confined concrete piles may be sign... more The surface topography of fibre-reinforced polymer (FRP) tube confined concrete piles may be significantly altered during the driving installation process. This change could affect the interface pile design parameters and therefore an accurate quantification of this change is required to precisely determine the pile shaft resistance. This article presents the results of an experimental study carried out to investigate the changes in surface topography and interface shear coefficient of two different FRP counterface surfaces that sheared against different types of sand under increased normal stress levels. The test results indicate that quantifiable surface topography changes could be induced by subjecting FRP surfaces to interface shearing under increased normal stress levels. Furthermore, the interface shear resistance coefficient decreases as the normal stress increases. The study also shows that the deterioration of the interface shear resistance coefficient as the normal stress ...
Mathematical Modelling of Engineering Problems, 2021
The term "reinforced soil" refers to a composite material with high tensile-strength co... more The term "reinforced soil" refers to a composite material with high tensile-strength components that enhance the soil's tensile strength. One of the most common kinds of geosynthetic fabric utilized for soil reinforcement is geotextiles. This article investigates woven geotextile's potential benefits in enhancing the maximum load-carrying capacity of footings resting upon silty sand soil. The foundation was constructed of a 10 mm thick strong carbon steel plate of 100 mm×100 mm. The factors examined in this research were the first geotextile layer's depth, the geotextile layer's width, the number of layers of reinforcing material, and the vertical spacing between geotextile layers. The impact of geotextile strengthening configurations on the load-carrying capacity of strengthened soil foundations was also studied. The results of the experiments indicated that geotextile reinforced soil could help to grow the soil bearing capacity. The testing findings revea...
Lowland technology international : the official journal of the International Association of Lowland Technology, 2014
Several studies in the literature have investigated the shear behaviour of soil-steel interface. ... more Several studies in the literature have investigated the shear behaviour of soil-steel interface. Furthermore, a normalized relative roughness parameter, R n , has been used successfully to describe the shear behaviour of the sandsteel interface. On the other hand, few studies are available in the literature regarding the interface shear behaviour of fiber reinforced polymer (FRP). The aim of this study is to investigate the shear behaviour of soil-FRP interface and examine the validity of R n for the FRP case. Experimental program using a modified direct shear test apparatus was conducted for this purpose. The testing materials in this study include two different types of FRP, and five different-size glass beads in terms of the mean particle size, D 50. The experimental results show that the interface shear behaviour of FRP is different than steel. The observed difference could be explained in terms of the expected contribution of the interface ploughing resistance in the FRP case compared to the steel where its interface shear behaviour is mainly controlled by the interface sliding resistance.
The improvement of sub-grade has always been significant aspect in highway and geotechnical engin... more The improvement of sub-grade has always been significant aspect in highway and geotechnical engineering fields. To strengthen the subgrade soil, the use of natural Jute fiber is advantageous because they are cheap, locally available, and biodegradable. In this paper the soil sample was compacted at its maximum dry density corresponding to its optimum moisture content in the Laboratory California Bearing Ratio (CBR) mould with and without natural Jute fiber. Natural Jute fiber sheets equal to the plan of CBR mould diameter were placed at various layers (second, fourth and fifth of soil's layers) to investigate its behaviour on CBR value. The experimental investigations were also involved natural Jute fiber coated with bitumen material to study the effect of bitumen material on the CBR value. The CBR values of soil and soil reinforced with Jute fiber were investigated in the geotechnical engineering laboratory. The results of experimental investigation showed that the inclusion of...
The geophysical testing is increasingly being employed in many geotechnical applications. It is p... more The geophysical testing is increasingly being employed in many geotechnical applications. It is preferred in monitoring the mechanical characteristics of the ground because of its economy, not time consuming and non-destructive nature. Seismic wave test is one of the geophysical methods which showed a potential in observing the general behaviour of the reinforced soil with stone columns. Findings in most cases showed that the seismic wave measurements was integrated with or compared to the conventional tests such as standard penetration test or cone penetration test. There was a noticeable success in identifying the enhancement achieved to the ground upon the strengthening with the column, specifically when the associated surveys can produce a clear image of the underground which interprets the variation in the soil properties not prior to the soil treatment only, but even after the treatment occurring. However, from practical point of view, there were still some restrictions with...
Fibre reinforced polymer (FRP) composites represent an alternative construction material for deep... more Fibre reinforced polymer (FRP) composites represent an alternative construction material for deep foundations that have the potential to eliminate most of the durability concerns associated with traditional piling materials. Research studies and database related to the use FRP composite material as piling foundation is very limited. This research project was undertaken to investigate the structural and geotechnical behaviour of FRP composite piles. The originality of this study rests on the following pillars:? Presenting a new understanding for the factors controlling the compressive strength of FRP tube confined concrete. ? Introducing the concept of constitutive interface surface which considers the effect of surface hardness and relative roughness on the interface shear coefficient. ? Studying the evolution of FRP pile surface roughness during the driving process. ? Investigating the effect of harsh environments on the shear behaviour of FRP-granular interface. ? Conducting an ex...
Abstract The application of FRP-confined concrete is recognized to be an effective solution to in... more Abstract The application of FRP-confined concrete is recognized to be an effective solution to increase the axial strength of many new and existing concrete columns. A number of experimental investigations and developments for numerical models have been established to understand the strength enhancement behaviour of the FRP-concrete confined section. This paper aims to investigate the influence of the confinement parameters including the concrete strength and the confining pressure on the strength enhancement of FRP-confined concrete specimens. Investigated data were collected from experimental works performed by the authors as well as results surveyed from state-of-the-art papers carefully selected and reviewed to provide an overview and in-depth knowledge in the development of this strengthening technique. Utilizing 927 experimental data from 127 papers from the literature, a 3-dimensional graph presentation (surface chart) have been utilized to investigate the strength enhancement of the FRP-confined concrete. This new graphing format assisted in demonstrating the non-linear influences for each of the parameters investigated on the confinement parameters on the strength enhancement of FRP-confined section. Unlike the conventional 2-dimensional plot of the confined concrete strength versus the confining pressure (both normalized by the unconfined concrete strength), the 3-dimensional graphing approach introduced in this paper is found to provide more information about the strength enhancement. Utilizing a Gauss surface fitting function, a refined enhancement ratio expression incorporating the individual influence of the confinement parameters is proposed in the paper and experimentally evaluated.
High-performance concrete mixes containing various proportions of natural pozzolan and silica fum... more High-performance concrete mixes containing various proportions of natural pozzolan and silica fume (up to 15% by weight of cement) were prepared and stored in sodium and magnesium sulfate solutions, in Dead Sea and Red Sea waters. The progressive deterioration and the relative sulfate resistance of these mixes were evaluated through visual observations, ultrasonic pulse velocity measurements, and relative strength determinations. The investigation indicated that the concrete mix containing 15% natural pozzolan, and 15% silica fume showed the best protection in sulfates solutions and sea waters. It retained more than 65% of its strength after one year of storage in sulfates solutions and sea waters. The superior resistance of that mix against sulfate attack is attributed to the pore refinement process and further densification of the transition zone occurring due to the conversion of lime forming from the hydration of cement into additional binding material through lime-pozzolan reaction. This investigation recommends the use of silica fume in combination with natural pozzolan for better performance in severe sulfate environments.
Pile foundations are commonly used to resist vertical and lateral loads applied to structures. Us... more Pile foundations are commonly used to resist vertical and lateral loads applied to structures. Usually, these kinds of loads will act together to form a combination of loads, such as oblique forces that have a component of vertical and lateral forc- es. Predicting the behavior of piles subjected to oblique loads still remains a challenging task to geotechnical engineers. In this paper, results of numerical simulation of behavior of piles as embedded in cohesionless soil under oblique loads are presented by using ABAQUS. For the cohesionless soil, the Mohr-Coloumb constitutive law has been used to simulate the surrounding soil while the linear elastic model is used for modeling of the pile. The interactions between the pile and the surrounding soil are modeled thoroughly using contact elements based on slave-master concept. The results are shown in terms of load/displacement curves for the components of vertical and the lateral loading portions in different inclination angles. Finall...
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