Sugarcane Bagasse Ash (SCBA) is one of the most common types of agricultural waste. By its availa... more Sugarcane Bagasse Ash (SCBA) is one of the most common types of agricultural waste. By its availability and pozzolanic properties, sugarcane bagasse ash can be utilized as a partial replacement for cement in the production of sustainable concrete. This study experimentally investigated the impact of employing two types of sugarcane bagasse ash as a partial substitute for cement up to 30% on the compressive strength, flexural strength, and Young’s modulus of the concrete mixture. The first type of bagasse ash used was raw SCBA, which was used as it arrived from the plant, with the same characteristics, considering that it was exposed to a temperature of 600 °C in the boilers to generate energy. The second type of bagasse ash utilized, called processed SCBA, was produced by regrinding raw SCBA for an hour and then burning it again for two hours at a temperature of 600 °C. This was done to improve the pozzolanic activity and consequently the mechanical properties of the concrete mixtur...
Fiber-reinforced polymer (FRP)-reinforced concrete (RC) elements fail under one-way shear in a de... more Fiber-reinforced polymer (FRP)-reinforced concrete (RC) elements fail under one-way shear in a devastating and complicated manner with no adequate warning. In recent decades, there has been pioneering research in this area; however, there is no agreement among researchers regarding mechanically-based models. Thus, in this current study, a plasticity-based model is developed for FRP-RC elements under shear. A selected model was firstly assessed for its accuracy, consistency, and safety against an extensive experimental database. Secondly, a plasticity-based model (i.e., crack shear sliding model) was adapted, refined, and proposed for FRP-RC elements under one-way shear. The two proposed models were found to be reliable and more accurate with respect to selected existing methods. Modeling of FRP’s axial rigidity is more consistent only under Young’s modulus with respect to the experimental database. Several concluding remarks on the selected existing models are outlined and discussed...
The shear behavior of concrete beams is highly affected by the implementation of better performan... more The shear behavior of concrete beams is highly affected by the implementation of better performance concrete. Hybrid fibers addition to concrete mixture has proven to improve the performance compared to just using single type of fiber. Thus, in this current study, the shear behavior of hybrid-fiber-reinforced-high-strength-concrete beams was investigated experimentally. In addition, the effect of the span-to-depth ratio and the transverse reinforcement ratio were examined. Results showed that, when .45% of the cement weight is replaced with polypropylene fiber and 7% of the cement weight is replaced with steel fibers, the shear strength of the beam was enhanced by 18% in comparison to the control beam. The Formation and progression of cracks were also better controlled. The behavior of hybrid-polypropylene-steel-fibers-high-strength-concrete beams was observed to be comparable to that of conventional concrete ones as the shear strength increased with the decrease in span to depth ra...
The recent failure of buildings because of punching shear has alerted researchers to assess the r... more The recent failure of buildings because of punching shear has alerted researchers to assess the reliability of the punching shear design models. However, most of the current research studies focus on model uncertainty compared to experimentally measured strength, while very limited studies consider the variability of the basic variables included in the model and the experimental measurements. This paper discusses the reliability of FRP-reinforced concrete slabs’ existing punching shear models. First, more than 180 specimens were gathered. Second, available design codes and simplified models were selected and used in the calculation. Third, several reliability methods were conducted; therefore, three methods were implemented, including the mean-value first-order second moment (MVFOSM) method, the first-order second moment (FOSM) method, and the second-order reliability method (SORM). A comparison between the three methods showed that the reliability index calculated using the FOSM is...
Very little is known about the shear behavior of elements, in particular those subjected to axial... more Very little is known about the shear behavior of elements, in particular those subjected to axial tension. The shear accompanied by tensile forces could cause premature failure of reinforced concrete, which is sudden with minimal warning. Therefore, understanding the shear behavior of reinforced concrete (RC) elements, including those subjected to axial tension, is an ultimate goal of the worldwide research community. In the current study, a new shear mechanical model for RC elements subjected to axial tension is developed, which makes physical sense and explains the behavior. The model is strain-based, inspired by the critical crack theory model (CSCT). In addition, the proposed model extended CSCT (ECSCT) quantifies the effect of axial tension forces on the shear strength in terms of reduction in the compression zone depth and increase in the longitudinal strain. Moreover, the nonlinear trend observed in the literature was implemented using nonlinear multi-variable regression. The...
Concrete-filled steel tube (CFST) columns are used in tall buildings and bridges, and they provid... more Concrete-filled steel tube (CFST) columns are used in tall buildings and bridges, and they provide more rigidity and higher bearing capacity, but buckling affects their behavior. There is an exceptional need to study the behavior of these columns under various conditions. The numerical method is beneficial in supplementing the experimental works and is used to explore the effects of various parameters because of the limitations in cost, apparatus, and time of the experimental program. The various parameters, such as the different slenderness ratios, i.e., column-height-to-cross-section-dimension (H/D), different steel-tube-thickness-to-column-dimension (D/t), and different compressive strength of concrete to yield strength of steel tube ratio (fc/fy) under concentric axial loading are considered in this current study. Firstly, a finite element model used the “ANSYS” software program and was constructed to validate the results of the experimental works. The extensive numerical models...
Despite significant advances in metallurgy and the potential to create high and very high-strengt... more Despite significant advances in metallurgy and the potential to create high and very high-strength steel, all international specifications for steel design provided little information about the limits of slenderness for high-strength steel sections (HSSs) and didn’t give anything about the design of very high-strength steel sections (VHSSs). The American structural steel design specification covers circular hollow sections (CHS) of steel grades up to S690, while it isn't in ANSI/AISC 360-16 and ASTM A514/A514M. Euro code EN 1993-1-1 can be applicable only to steel grades up to S460. EN 1993-1-3 and EN 1993-1-12 contain supplementary rules for cold-formed members and HSS (S460- S700), respectively. Though ductility requirements for (HSS) are specifically established in EN 1993-1-12, it is largely a continuation of the normal-strength-steel design procedures standardized in EN 1993-1-1, where (HSSs) are largely treated as normal-strength steels in these rules, and the same design ...
This study aims to investigate the two-way shear strength of concrete slabs with FRP reinforcemen... more This study aims to investigate the two-way shear strength of concrete slabs with FRP reinforcements. Twenty-one strength models were briefly outlined and compared. In addition, information on a total of 248 concrete slabs with FRP reinforcements were collected from 50 different research studies. Moreover, behavior trends and correlations between their strength and various parameters were identified and discussed. Strength models were compared to each other with respect to the experimentally measured strength, which were conducted by comparing overall performance versus selected basic variables. Areas of future research were identified. Concluding remarks were outlined and discussed, which could help further the development of future design codes. The ACI is the least consistent model because it does not include the effects of size, dowel action, and depth-to-control perimeter ratio. While the EE-b is the most consistent model with respect to the size effect, concrete compressive str...
In the last few decades, the concrete industry has been massively expanded with the adoption of v... more In the last few decades, the concrete industry has been massively expanded with the adoption of various kinds of binding materials. As a substitute to cement and in an effort to relieve ecofriendly difficulties linked with cement creation, the utilization of industrial waste as cementitious material can sharply reduce the amount of trash disposed of in lakes and landfills. With respect to the mechanical properties, durability and thermal behavior, ground-granulated blast-furnace slag (GGBS) delineates a rational way to develop sustainable cement and concrete. Apart from environmental benefits, the replacement of cement by GGBS illustrates an adequate way to mitigate the economic impact. Although many researchers concentrate on utilizing GGBS in concrete production, knowledge is scattered, and additional research is needed to better understand relationships among a wide spectrum of key questions and to more accurately determine these preliminary findings. This work aims to shed some ...
Recently, research has centered on developing new approaches, such as supervised machine learning... more Recently, research has centered on developing new approaches, such as supervised machine learning techniques, that can compute the mechanical characteristics of materials without investing much effort, time, or money in experimentation. To predict the 28-day compressive strength of steel fiber–reinforced concrete (SFRC), machine learning techniques, i.e., individual and ensemble models, were considered. For this study, two ensemble approaches (SVR AdaBoost and SVR bagging) and one individual technique (support vector regression (SVR)) were used. Coefficient of determination (R2), statistical assessment, and k-fold cross validation were carried out to scrutinize the efficiency of each approach used. In addition, a sensitivity technique was used to assess the influence of parameters on the prediction results. It was discovered that all of the approaches used performed better in terms of forecasting the outcomes. The SVR AdaBoost method was the most precise, with R2 = 0.96, as opposed ...
In civil engineering, ultra-high-strength concrete (UHSC) is a useful and efficient building mate... more In civil engineering, ultra-high-strength concrete (UHSC) is a useful and efficient building material. To save money and time in the construction sector, soft computing approaches have been used to estimate concrete properties. As a result, the current work used sophisticated soft computing techniques to estimate the compressive strength of UHSC. In this study, XGBoost, AdaBoost, and Bagging were the employed soft computing techniques. The variables taken into account included cement content, fly ash, silica fume and silicate content, sand and water content, superplasticizer content, steel fiber, steel fiber aspect ratio, and curing time. The algorithm performance was evaluated using statistical metrics, such as the mean absolute error (MAE), root mean square error (RMSE), and coefficient of determination (R2). The model’s performance was then evaluated statistically. The XGBoost soft computing technique, with a higher R2 (0.90) and low errors, was more accurate than the other algor...
The failure of structural elements caused by corrosion of conventional steel reinforcements direc... more The failure of structural elements caused by corrosion of conventional steel reinforcements directed researchers all over the world to investigate the repairing of existing steel RC elements or find viable substitutes for reinforcing new RC elements. For existing structural elements, FRP fabrics are being studied as external reinforcement for the purpose of repairing RC elements deteriorated due to corrosion of steel reinforcements. On the other hand, for new structural elements, FRP bars are being investigated as non-corrosive internal reinforcements. The torsional behavior of FRP-internally reinforced concrete beams was not fully investigated. Previous studies showed that bended GFRP stirrup is inadequate. In this paper, a new technique for forming the stirrup without bent is introduced. In addition, the effectiveness of replacing steel bars and/or steel stirrups with GFRP bars and/or glued GFRP stirrups for reinforcing L-shaped beams under torsion is examined. Three L-shaped beam...
Concrete-filled steel tubular (CFST) beam-columns are widely used owing to their good performance... more Concrete-filled steel tubular (CFST) beam-columns are widely used owing to their good performance. They have high strength, ductility, large energy absorption capacity and low costs. Externally stiffened CFST beam-columns are not used widely due to insufficient design equations that consider all parameters affecting their behavior. Therefore, effect of various parameters (global, local slenderness ratio and adding hoop stiffeners) on the behavior of CFST columns is studied. An experimental study that includes twenty seven specimens is conducted to determine the effect of those parameters. Load capacities, vertical deflections, vertical strains and horizontal strains are all recorded for every specimen. Ratio between outer diameter (D) of pipes and thickness (t) is chosen to avoid local buckling according to different limits set by codes for the maximum D/t ratio. The study includes two loading methods on composite sections: steel only and steel with concrete. The case of loading on ...
Introduction Openings are needed in reinforced concrete (RC) structures, which allow the executio... more Introduction Openings are needed in reinforced concrete (RC) structures, which allow the execution of the electromechanical plumbing system. Using opening through the beam web, leads to a substantial reduction in the cost. In addition, the opening locations are decided by the electromechanical plumbing design, irrelevant of the structural aspect. Which could lead to situation where opening are nearby beam-column joints at the plastic hinge zone. The recommended design philosophy is “strong column weak beam”, which ensure the formation of the plastic hinge in the beam, rather than in the column. However, a nearby web opening could significantly affect the behavior of the beam-column joint. Due to the severity of the Beam-Column joint, its behavior has been the subject of several research studies [1-3]. RC Beam-Column joint failure may lead to a catastrophic collapse of structures [4-7] due to large deformation. Failure of Beam-Column joints is due to various factors such as poor rein...
Recently, strengthening of reinforced concrete (RC) beams subjected to torsion is receiving incre... more Recently, strengthening of reinforced concrete (RC) beams subjected to torsion is receiving increased attention. Using Fiber reinforced polymers (FRP) for torsion strengthening of RC beams was found to be an effective solution in many cases. However, there are no available rational analytical models for this case. In the current study, a simplified model for strengthening of RC beams subjected to torsion is presented and numerically validated. The proposed model takes into account the effect of various parameters including different failure modes. The model is validated using an experimental database collected from several sources. The model showed good agreement with the experimental results. In addition, it was compared to an available design procedure. The proposed model represented the behaviour and predicted the strength of the beams more accurately than previous design models.
The durability of concrete elements reinforced with conventional steel has been questionable. Ste... more The durability of concrete elements reinforced with conventional steel has been questionable. Steel bars will eventually deteriorate due to corrosion especially in harsh environments and water structures. FRP reinforcement bars manufactured made of resin impregnated FRP. FRP bars are non-corrosive with high strength to weight ratio which makes it an ideal substitute for conventional steel bars. However, previous studies showed that the bent of the FRP stirrups could cause reduction in the strength and might lead to inadequate performance. This paper introduces a new technique for forming the stirrup and experimentally investigating the torsional behavior of FRP-reinforced concrete beams. Three spandrel beams were tested under pure torsion while reinforced with FRP bars in both the transversal and longitudinal direction of the tested beam. The three beams had the same cross section dimensions, reinforcement detailing, and stirrup spacing. The main parameter investigated was the stirr...
Most of the previous research focused on either behavior of reinforced concrete (RC) beams with o... more Most of the previous research focused on either behavior of reinforced concrete (RC) beams with openings [1] or shear behavior of RC beam-column joints [2]; however, very limited studies tackled the behavior of RC beam-column joints with nearby beam web openings. In this paper, the influence of a nearby RC beam web opening properties (i.e. aspect ratio and location) on the behavior (i.e. cracking pattern, failure mode, stiffness degradation, steel reinforcement strain, energy dissipation, load displacement envelope, strength, and ductility) of an RC beam-column joint are being investigated. In addition, the effect of different additional reinforcement around the opening was investigated. Concluding remarks were outlined. -------------------------------------------------------------------------------------------------------------------------------------Date of Submission: 15 -07-2017 Date of acceptance: 28-08-2017 ----------------------------------------------------------------------...
Sugarcane Bagasse Ash (SCBA) is one of the most common types of agricultural waste. By its availa... more Sugarcane Bagasse Ash (SCBA) is one of the most common types of agricultural waste. By its availability and pozzolanic properties, sugarcane bagasse ash can be utilized as a partial replacement for cement in the production of sustainable concrete. This study experimentally investigated the impact of employing two types of sugarcane bagasse ash as a partial substitute for cement up to 30% on the compressive strength, flexural strength, and Young’s modulus of the concrete mixture. The first type of bagasse ash used was raw SCBA, which was used as it arrived from the plant, with the same characteristics, considering that it was exposed to a temperature of 600 °C in the boilers to generate energy. The second type of bagasse ash utilized, called processed SCBA, was produced by regrinding raw SCBA for an hour and then burning it again for two hours at a temperature of 600 °C. This was done to improve the pozzolanic activity and consequently the mechanical properties of the concrete mixtur...
Fiber-reinforced polymer (FRP)-reinforced concrete (RC) elements fail under one-way shear in a de... more Fiber-reinforced polymer (FRP)-reinforced concrete (RC) elements fail under one-way shear in a devastating and complicated manner with no adequate warning. In recent decades, there has been pioneering research in this area; however, there is no agreement among researchers regarding mechanically-based models. Thus, in this current study, a plasticity-based model is developed for FRP-RC elements under shear. A selected model was firstly assessed for its accuracy, consistency, and safety against an extensive experimental database. Secondly, a plasticity-based model (i.e., crack shear sliding model) was adapted, refined, and proposed for FRP-RC elements under one-way shear. The two proposed models were found to be reliable and more accurate with respect to selected existing methods. Modeling of FRP’s axial rigidity is more consistent only under Young’s modulus with respect to the experimental database. Several concluding remarks on the selected existing models are outlined and discussed...
The shear behavior of concrete beams is highly affected by the implementation of better performan... more The shear behavior of concrete beams is highly affected by the implementation of better performance concrete. Hybrid fibers addition to concrete mixture has proven to improve the performance compared to just using single type of fiber. Thus, in this current study, the shear behavior of hybrid-fiber-reinforced-high-strength-concrete beams was investigated experimentally. In addition, the effect of the span-to-depth ratio and the transverse reinforcement ratio were examined. Results showed that, when .45% of the cement weight is replaced with polypropylene fiber and 7% of the cement weight is replaced with steel fibers, the shear strength of the beam was enhanced by 18% in comparison to the control beam. The Formation and progression of cracks were also better controlled. The behavior of hybrid-polypropylene-steel-fibers-high-strength-concrete beams was observed to be comparable to that of conventional concrete ones as the shear strength increased with the decrease in span to depth ra...
The recent failure of buildings because of punching shear has alerted researchers to assess the r... more The recent failure of buildings because of punching shear has alerted researchers to assess the reliability of the punching shear design models. However, most of the current research studies focus on model uncertainty compared to experimentally measured strength, while very limited studies consider the variability of the basic variables included in the model and the experimental measurements. This paper discusses the reliability of FRP-reinforced concrete slabs’ existing punching shear models. First, more than 180 specimens were gathered. Second, available design codes and simplified models were selected and used in the calculation. Third, several reliability methods were conducted; therefore, three methods were implemented, including the mean-value first-order second moment (MVFOSM) method, the first-order second moment (FOSM) method, and the second-order reliability method (SORM). A comparison between the three methods showed that the reliability index calculated using the FOSM is...
Very little is known about the shear behavior of elements, in particular those subjected to axial... more Very little is known about the shear behavior of elements, in particular those subjected to axial tension. The shear accompanied by tensile forces could cause premature failure of reinforced concrete, which is sudden with minimal warning. Therefore, understanding the shear behavior of reinforced concrete (RC) elements, including those subjected to axial tension, is an ultimate goal of the worldwide research community. In the current study, a new shear mechanical model for RC elements subjected to axial tension is developed, which makes physical sense and explains the behavior. The model is strain-based, inspired by the critical crack theory model (CSCT). In addition, the proposed model extended CSCT (ECSCT) quantifies the effect of axial tension forces on the shear strength in terms of reduction in the compression zone depth and increase in the longitudinal strain. Moreover, the nonlinear trend observed in the literature was implemented using nonlinear multi-variable regression. The...
Concrete-filled steel tube (CFST) columns are used in tall buildings and bridges, and they provid... more Concrete-filled steel tube (CFST) columns are used in tall buildings and bridges, and they provide more rigidity and higher bearing capacity, but buckling affects their behavior. There is an exceptional need to study the behavior of these columns under various conditions. The numerical method is beneficial in supplementing the experimental works and is used to explore the effects of various parameters because of the limitations in cost, apparatus, and time of the experimental program. The various parameters, such as the different slenderness ratios, i.e., column-height-to-cross-section-dimension (H/D), different steel-tube-thickness-to-column-dimension (D/t), and different compressive strength of concrete to yield strength of steel tube ratio (fc/fy) under concentric axial loading are considered in this current study. Firstly, a finite element model used the “ANSYS” software program and was constructed to validate the results of the experimental works. The extensive numerical models...
Despite significant advances in metallurgy and the potential to create high and very high-strengt... more Despite significant advances in metallurgy and the potential to create high and very high-strength steel, all international specifications for steel design provided little information about the limits of slenderness for high-strength steel sections (HSSs) and didn’t give anything about the design of very high-strength steel sections (VHSSs). The American structural steel design specification covers circular hollow sections (CHS) of steel grades up to S690, while it isn't in ANSI/AISC 360-16 and ASTM A514/A514M. Euro code EN 1993-1-1 can be applicable only to steel grades up to S460. EN 1993-1-3 and EN 1993-1-12 contain supplementary rules for cold-formed members and HSS (S460- S700), respectively. Though ductility requirements for (HSS) are specifically established in EN 1993-1-12, it is largely a continuation of the normal-strength-steel design procedures standardized in EN 1993-1-1, where (HSSs) are largely treated as normal-strength steels in these rules, and the same design ...
This study aims to investigate the two-way shear strength of concrete slabs with FRP reinforcemen... more This study aims to investigate the two-way shear strength of concrete slabs with FRP reinforcements. Twenty-one strength models were briefly outlined and compared. In addition, information on a total of 248 concrete slabs with FRP reinforcements were collected from 50 different research studies. Moreover, behavior trends and correlations between their strength and various parameters were identified and discussed. Strength models were compared to each other with respect to the experimentally measured strength, which were conducted by comparing overall performance versus selected basic variables. Areas of future research were identified. Concluding remarks were outlined and discussed, which could help further the development of future design codes. The ACI is the least consistent model because it does not include the effects of size, dowel action, and depth-to-control perimeter ratio. While the EE-b is the most consistent model with respect to the size effect, concrete compressive str...
In the last few decades, the concrete industry has been massively expanded with the adoption of v... more In the last few decades, the concrete industry has been massively expanded with the adoption of various kinds of binding materials. As a substitute to cement and in an effort to relieve ecofriendly difficulties linked with cement creation, the utilization of industrial waste as cementitious material can sharply reduce the amount of trash disposed of in lakes and landfills. With respect to the mechanical properties, durability and thermal behavior, ground-granulated blast-furnace slag (GGBS) delineates a rational way to develop sustainable cement and concrete. Apart from environmental benefits, the replacement of cement by GGBS illustrates an adequate way to mitigate the economic impact. Although many researchers concentrate on utilizing GGBS in concrete production, knowledge is scattered, and additional research is needed to better understand relationships among a wide spectrum of key questions and to more accurately determine these preliminary findings. This work aims to shed some ...
Recently, research has centered on developing new approaches, such as supervised machine learning... more Recently, research has centered on developing new approaches, such as supervised machine learning techniques, that can compute the mechanical characteristics of materials without investing much effort, time, or money in experimentation. To predict the 28-day compressive strength of steel fiber–reinforced concrete (SFRC), machine learning techniques, i.e., individual and ensemble models, were considered. For this study, two ensemble approaches (SVR AdaBoost and SVR bagging) and one individual technique (support vector regression (SVR)) were used. Coefficient of determination (R2), statistical assessment, and k-fold cross validation were carried out to scrutinize the efficiency of each approach used. In addition, a sensitivity technique was used to assess the influence of parameters on the prediction results. It was discovered that all of the approaches used performed better in terms of forecasting the outcomes. The SVR AdaBoost method was the most precise, with R2 = 0.96, as opposed ...
In civil engineering, ultra-high-strength concrete (UHSC) is a useful and efficient building mate... more In civil engineering, ultra-high-strength concrete (UHSC) is a useful and efficient building material. To save money and time in the construction sector, soft computing approaches have been used to estimate concrete properties. As a result, the current work used sophisticated soft computing techniques to estimate the compressive strength of UHSC. In this study, XGBoost, AdaBoost, and Bagging were the employed soft computing techniques. The variables taken into account included cement content, fly ash, silica fume and silicate content, sand and water content, superplasticizer content, steel fiber, steel fiber aspect ratio, and curing time. The algorithm performance was evaluated using statistical metrics, such as the mean absolute error (MAE), root mean square error (RMSE), and coefficient of determination (R2). The model’s performance was then evaluated statistically. The XGBoost soft computing technique, with a higher R2 (0.90) and low errors, was more accurate than the other algor...
The failure of structural elements caused by corrosion of conventional steel reinforcements direc... more The failure of structural elements caused by corrosion of conventional steel reinforcements directed researchers all over the world to investigate the repairing of existing steel RC elements or find viable substitutes for reinforcing new RC elements. For existing structural elements, FRP fabrics are being studied as external reinforcement for the purpose of repairing RC elements deteriorated due to corrosion of steel reinforcements. On the other hand, for new structural elements, FRP bars are being investigated as non-corrosive internal reinforcements. The torsional behavior of FRP-internally reinforced concrete beams was not fully investigated. Previous studies showed that bended GFRP stirrup is inadequate. In this paper, a new technique for forming the stirrup without bent is introduced. In addition, the effectiveness of replacing steel bars and/or steel stirrups with GFRP bars and/or glued GFRP stirrups for reinforcing L-shaped beams under torsion is examined. Three L-shaped beam...
Concrete-filled steel tubular (CFST) beam-columns are widely used owing to their good performance... more Concrete-filled steel tubular (CFST) beam-columns are widely used owing to their good performance. They have high strength, ductility, large energy absorption capacity and low costs. Externally stiffened CFST beam-columns are not used widely due to insufficient design equations that consider all parameters affecting their behavior. Therefore, effect of various parameters (global, local slenderness ratio and adding hoop stiffeners) on the behavior of CFST columns is studied. An experimental study that includes twenty seven specimens is conducted to determine the effect of those parameters. Load capacities, vertical deflections, vertical strains and horizontal strains are all recorded for every specimen. Ratio between outer diameter (D) of pipes and thickness (t) is chosen to avoid local buckling according to different limits set by codes for the maximum D/t ratio. The study includes two loading methods on composite sections: steel only and steel with concrete. The case of loading on ...
Introduction Openings are needed in reinforced concrete (RC) structures, which allow the executio... more Introduction Openings are needed in reinforced concrete (RC) structures, which allow the execution of the electromechanical plumbing system. Using opening through the beam web, leads to a substantial reduction in the cost. In addition, the opening locations are decided by the electromechanical plumbing design, irrelevant of the structural aspect. Which could lead to situation where opening are nearby beam-column joints at the plastic hinge zone. The recommended design philosophy is “strong column weak beam”, which ensure the formation of the plastic hinge in the beam, rather than in the column. However, a nearby web opening could significantly affect the behavior of the beam-column joint. Due to the severity of the Beam-Column joint, its behavior has been the subject of several research studies [1-3]. RC Beam-Column joint failure may lead to a catastrophic collapse of structures [4-7] due to large deformation. Failure of Beam-Column joints is due to various factors such as poor rein...
Recently, strengthening of reinforced concrete (RC) beams subjected to torsion is receiving incre... more Recently, strengthening of reinforced concrete (RC) beams subjected to torsion is receiving increased attention. Using Fiber reinforced polymers (FRP) for torsion strengthening of RC beams was found to be an effective solution in many cases. However, there are no available rational analytical models for this case. In the current study, a simplified model for strengthening of RC beams subjected to torsion is presented and numerically validated. The proposed model takes into account the effect of various parameters including different failure modes. The model is validated using an experimental database collected from several sources. The model showed good agreement with the experimental results. In addition, it was compared to an available design procedure. The proposed model represented the behaviour and predicted the strength of the beams more accurately than previous design models.
The durability of concrete elements reinforced with conventional steel has been questionable. Ste... more The durability of concrete elements reinforced with conventional steel has been questionable. Steel bars will eventually deteriorate due to corrosion especially in harsh environments and water structures. FRP reinforcement bars manufactured made of resin impregnated FRP. FRP bars are non-corrosive with high strength to weight ratio which makes it an ideal substitute for conventional steel bars. However, previous studies showed that the bent of the FRP stirrups could cause reduction in the strength and might lead to inadequate performance. This paper introduces a new technique for forming the stirrup and experimentally investigating the torsional behavior of FRP-reinforced concrete beams. Three spandrel beams were tested under pure torsion while reinforced with FRP bars in both the transversal and longitudinal direction of the tested beam. The three beams had the same cross section dimensions, reinforcement detailing, and stirrup spacing. The main parameter investigated was the stirr...
Most of the previous research focused on either behavior of reinforced concrete (RC) beams with o... more Most of the previous research focused on either behavior of reinforced concrete (RC) beams with openings [1] or shear behavior of RC beam-column joints [2]; however, very limited studies tackled the behavior of RC beam-column joints with nearby beam web openings. In this paper, the influence of a nearby RC beam web opening properties (i.e. aspect ratio and location) on the behavior (i.e. cracking pattern, failure mode, stiffness degradation, steel reinforcement strain, energy dissipation, load displacement envelope, strength, and ductility) of an RC beam-column joint are being investigated. In addition, the effect of different additional reinforcement around the opening was investigated. Concluding remarks were outlined. -------------------------------------------------------------------------------------------------------------------------------------Date of Submission: 15 -07-2017 Date of acceptance: 28-08-2017 ----------------------------------------------------------------------...
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