The objective of the present manuscript is to describe the impact of polypropylene fibers on the behavior of heated concrete subjected to heating and cooling cycles at temperatures of 200, 450 and 600 °C respectively for six hours, through a series of experimental tests on mass loss, water absorption, porosity, compressive and tensile strength. For this purpose, mixes were prepared with a water/cement ratio with the incorporation of polypropylene fibers with a rate varying from 0.5 to 1.5%. These fibers were added in order to improve the thermal stability and to prevent the concrete from splitting. The results show that a considerable loss of strength was noticed for all tested specimens. The relative compressive strengths of the concretes containing polypropylene fibers were higher than those of the concretes without fibers. Also, a greater loss of mass of the polypropylene fibers compared to those without fibers was noticed when increasing the temperature. The flexural tensile strength of the concrete was more sensitive to elevated temperatures than the compressive strength and a rapid increase in porosity was observed for the fiber-reinforced concrete compared to the reference concrete. Furthermore, water absorption by the fibers is proportional to the fiber content of the concrete.

The objective of the present manuscript is to describe the impact of polypropylene fibers on the behavior of heated concrete subjected to heating and cooling cycles at temperatures of 200, 450 and 600 °C respectively for six hours, through a series of experimental tests on mass loss, water absorption, porosity, compressive and tensile strength. For this purpose, mixes were prepared with a water/cement ratio with the incorporation of polypropylene fibers with a rate varying from 0.5 to 1.5%. These fibers were added in order to improve the thermal stability and to prevent the concrete from splitting. The results show that a considerable loss of strength was noticed for all tested specimens. The relative compressive strengths of the concretes containing polypropylene fibers were higher than those of the concretes without fibers. Also, a greater loss of mass of the polypropylene fibers compared to those without fibers was noticed when increasing the temperature. The flexural tensile strength of the concrete was more sensitive to elevated temperatures than the compressive strength and a rapid increase in porosity was observed for the fiber-reinforced concrete compared to the reference concrete. Furthermore, water absorption by the fibers is proportional to the fiber content of the concrete.

The objective of the present manuscript is to describe the impact of polypropylene fibers on the behavior of heated concrete subjected to heating and cooling cycles at temperatures of 200, 450 and 600 °C respectively for six hours, through a series of experimental tests on mass loss, water absorption, porosity, compressive and tensile strength. For this purpose, mixes were prepared with a water/cement ratio with the incorporation of polypropylene fibers with a rate varying from 0.5 to 1.5%. These fibers were added in order to improve the thermal stability and to prevent the concrete from splitting. The results show that a considerable loss of strength was noticed for all tested specimens. The relative compressive strengths of the concretes containing polypropylene fibers were higher than those of the concretes without fibers. Also, a greater loss of mass of the polypropylene fibers compared to those without fibers was noticed when increasing the temperature. The flexural tensile strength of the concrete was more sensitive to elevated temperatures than the compressive strength and a rapid increase in porosity was observed for the fiber-reinforced concrete compared to the reference concrete. Furthermore, water absorption by the fibers is proportional to the fiber content of the concrete.

The objective of the present manuscript is to describe the impact of polypropylene fibers on the behavior of heated concrete subjected to heating and cooling cycles at temperatures of 200, 450 and 600 °C respectively for six hours, through a series of experimental tests on mass loss, water absorption, porosity, compressive and tensile strength. For this purpose, mixes were prepared with a water/cement ratio with the incorporation of polypropylene fibers with a rate varying from 0.5 to 1.5%. These fibers were added in order to improve the thermal stability and to prevent the concrete from splitting. The results show that a considerable loss of strength was noticed for all tested specimens. The relative compressive strengths of the concretes containing polypropylene fibers were higher than those of the concretes without fibers. Also, a greater loss of mass of the polypropylene fibers compared to those without fibers was noticed when increasing the temperature. The flexural tensile strength of the concrete was more sensitive to elevated temperatures than the compressive strength and a rapid increase in porosity was observed for the fiber-reinforced concrete compared to the reference concrete. Furthermore, water absorption by the fibers is proportional to the fiber content of the concrete.

The objective of the present manuscript is to describe the impact of polypropylene fibers on the behavior of heated concrete subjected to heating and cooling cycles at temperatures of 200, 450 and 600 °C respectively for six hours, through a series of experimental tests on mass loss, water absorption, porosity, compressive and tensile strength. For this purpose, mixes were prepared with a water/cement ratio with the incorporation of polypropylene fibers with a rate varying from 0.5 to 1.5%. These fibers were added in order to improve the thermal stability and to prevent the concrete from splitting. The results show that a considerable loss of strength was noticed for all tested specimens. The relative compressive strengths of the concretes containing polypropylene fibers were higher than those of the concretes without fibers. Also, a greater loss of mass of the polypropylene fibers compared to those without fibers was noticed when increasing the temperature. The flexural tensile strength of the concrete was more sensitive to elevated temperatures than the compressive strength and a rapid increase in porosity was observed for the fiber-reinforced concrete compared to the reference concrete. Furthermore, water absorption by the fibers is proportional to the fiber content of the concrete.

The stability and strength of slender Reinforced Concrete (RC) columns depend directly on the flexural stiffness EI, which is a major parameter in strain calculations including those with bending and axial load. Due to the non-linearity of the stress-strain curve of concrete, the effective bending stiffness EI always remains variable. Numerical simulations were performed for square and L-shaped reinforced concrete sections of slender columns subjected to an eccentric axial force to estimate the variation of El resulting from the actual behavior of the column, based on the moment-curvature relationship. Seventy thousand (70000) hypothetical slender columns, each with a different combination of variables, were used to investigate the main variables that affect the EI of RC slender columns. Using linear regression analysis, a new simple and linear expression of EI was developed. Slenderness, axial load level, and concrete strength have been identified as the most important factors affecting effective stiffness. Finally, the comparison between the results of the new equation and the methods proposed by ACI-318 and Euro Code-2 was carried out in connection with the experimental results of the literature. A good agreement of the results was found.

The stability and strength of slender Reinforced Concrete (RC) columns depend directly on the flexural stiffness EI, which is a major parameter in strain calculations including those with bending and axial load. Due to the non-linearity of the stress-strain curve of concrete, the effective bending stiffness EI always remains variable. Numerical simulations were performed for square and L-shaped reinforced concrete sections of slender columns subjected to an eccentric axial force to estimate the variation of El resulting from the actual behavior of the column, based on the moment-curvature relationship. Seventy thousand (70000) hypothetical slender columns, each with a different combination of variables, were used to investigate the main variables that affect the EI of RC slender columns. Using linear regression analysis, a new simple and linear expression of EI was developed. Slenderness, axial load level, and concrete strength have been identified as the most important factors affecting effective stiffness. Finally, the comparison between the results of the new equation and the methods proposed by ACI-318 and Euro Code-2 was carried out in connection with the experimental results of the literature. A good agreement of the results was found.

A steel frame with a semi-rigid connection is one of the most widely used structural systems in modern construction. These systems are cheap to make, require less time to construct and offer the highest quality and reliable construction quality without the need for highly skilled workers. However, these systems show greater natural periods compared to their perfectly rigid frame counterparts. This causes the building to attract low loads during earthquakes. In this research study, the seismic performance of steel frames with semi-rigid joints is evaluated. Three connections with capacities of 50, 70 and 100% of the beam’s plastic moment are studied and examined. The seismic performance of these frames is determined by a non-linear static pushover analysis and an incremental dynamic analysis leading finally to the fragility curves which are developed. The results show that a decrease in the connection capacity increases the probability of reaching or exceeding a particular damage limit state in the frames is found.

A steel frame with a semi-rigid connection is one of the most widely used structural systems in modern construction. These systems are cheap to make, require less time to construct and offer the highest quality and reliable construction quality without the need for highly skilled workers. However, these systems show greater natural periods compared to their perfectly rigid frame counterparts. This causes the building to attract low loads during earthquakes. In this research study, the seismic performance of steel frames with semi-rigid joints is evaluated. Three connections with capacities of 50, 70 and 100% of the beam’s plastic moment are studied and examined. The seismic performance of these frames is determined by a non-linear static pushover analysis and an incremental dynamic analysis leading finally to the fragility curves which are developed. The results show that a decrease in the connection capacity increases the probability of reaching or exceeding a particular damage limit state in the frames is found.

A steel frame with a semi-rigid connection is one of the most widely used structural systems in modern construction. These systems are cheap to make, require less time to construct and offer the highest quality and reliable construction quality without the need for highly skilled workers. However, these systems show greater natural periods compared to their perfectly rigid frame counterparts. This causes the building to attract low loads during earthquakes. In this research study, the seismic performance of steel frames with semi-rigid joints is evaluated. Three connections with capacities of 50, 70 and 100% of the beam’s plastic moment are studied and examined. The seismic performance of these frames is determined by a non-linear static pushover analysis and an incremental dynamic analysis leading finally to the fragility curves which are developed. The results show that a decrease in the connection capacity increases the probability of reaching or exceeding a particular damage limit state in the frames is found.

A steel frame with a semi-rigid connection is one of the most widely used structural systems in modern construction. These systems are cheap to make, require less time to construct and offer the highest quality and reliable construction quality without the need for highly skilled workers. However, these systems show greater natural periods compared to their perfectly rigid frame counterparts. This causes the building to attract low loads during earthquakes. In this research study, the seismic performance of steel frames with semi-rigid joints is evaluated. Three connections with capacities of 50, 70 and 100% of the beam’s plastic moment are studied and examined. The seismic performance of these frames is determined by a non-linear static pushover analysis and an incremental dynamic analysis leading finally to the fragility curves which are developed. The results show that a decrease in the connection capacity increases the probability of reaching or exceeding a particular damage limit state in the frames is found.

This work deals with the performance improvement study of the direct torque control (DTC) of induction Motor (IM) based on Fuzzy Second Order Sliding Mode Control (FSOSMC). Direct torque control using conventional Second Order Sliding Mode Control regulators has certain disadvantages such as significant flux, torque ripples and sensitivity to parametric variations. To overcome these drawbacks, we apply a new type with more robust regulators such as the fuzzy second order sliding mode control. In recent years, Ant Colony Optimization (ACO) algorithm have attracted considerable attention among various modern heuristic optimization techniques. This paper proposes the ant colony optimization algorithm with fuzzy second order sliding mode controller based direct torque control of induction motor to enhance the system performance and stability. Simulation results demonstrate the feasibility and validity of the proposed DTC-FSOSMC system by effectively accelerating system response, reducing torque and flux ripple and a very satisfactory performance has been achieved.

This work deals with the performance improvement study of the direct torque control (DTC) of induction Motor (IM) based on Fuzzy Second Order Sliding Mode Control (FSOSMC). Direct torque control using conventional Second Order Sliding Mode Control regulators has certain disadvantages such as significant flux, torque ripples and sensitivity to parametric variations. To overcome these drawbacks, we apply a new type with more robust regulators such as the fuzzy second order sliding mode control. In recent years, Ant Colony Optimization (ACO) algorithm have attracted considerable attention among various modern heuristic optimization techniques. This paper proposes the ant colony optimization algorithm with fuzzy second order sliding mode controller based direct torque control of induction motor to enhance the system performance and stability. Simulation results demonstrate the feasibility and validity of the proposed DTC-FSOSMC system by effectively accelerating system response, reducing torque and flux ripple and a very satisfactory performance has been achieved.

This work deals with the performance improvement study of the direct torque control (DTC) of induction Motor (IM) based on Fuzzy Second Order Sliding Mode Control (FSOSMC). Direct torque control using conventional Second Order Sliding Mode Control regulators has certain disadvantages such as significant flux, torque ripples and sensitivity to parametric variations. To overcome these drawbacks, we apply a new type with more robust regulators such as the fuzzy second order sliding mode control. In recent years, Ant Colony Optimization (ACO) algorithm have attracted considerable attention among various modern heuristic optimization techniques. This paper proposes the ant colony optimization algorithm with fuzzy second order sliding mode controller based direct torque control of induction motor to enhance the system performance and stability. Simulation results demonstrate the feasibility and validity of the proposed DTC-FSOSMC system by effectively accelerating system response, reducing torque and flux ripple and a very satisfactory performance has been achieved.

This work deals with the study and performance improvement of the direct power control of DFIG based on backstepping Controller. Direct power control using hysteresis regulator has certain disadvantages such as significant powers ripples, variable switching frequency and sensitivity to parametric variations. To surmount these disadvantages, we present a robust controller such as the backstepping-based direct power control using SVM. A comparison study was made between the classic direct power control and the backstepping controller. The simulation results show that the backstepping controller provides good results reduces powers ripples.

This work deals with the study and performance improvement of the direct power control of DFIG based on backstepping Controller. Direct power control using hysteresis regulator has certain disadvantages such as significant powers ripples, variable switching frequency and sensitivity to parametric variations. To surmount these disadvantages, we present a robust controller such as the backstepping-based direct power control using SVM. A comparison study was made between the classic direct power control and the backstepping controller. The simulation results show that the backstepping controller provides good results reduces powers ripples.

This work deals with the study and performance improvement of the direct power control of DFIG based on backstepping Controller. Direct power control using hysteresis regulator has certain disadvantages such as significant powers ripples, variable switching frequency and sensitivity to parametric variations. To surmount these disadvantages, we present a robust controller such as the backstepping-based direct power control using SVM. A comparison study was made between the classic direct power control and the backstepping controller. The simulation results show that the backstepping controller provides good results reduces powers ripples.