Salah El-Metwally | Mansoura University (original) (raw)
Papers by Salah El-Metwally
The relevant detailing of joint reinforcement plays a major role in ensuring adequate performance... more The relevant detailing of joint reinforcement plays a major role in ensuring adequate performance of reinforced concrete frames in terms of strength and ductility. The reinforcement detailing of joints with U-shaped bars in most common codes is achieved by providing a minimum stirrups reinforcement ratio and a maximum spacing between them; however, the contribution of the cross ties configuration within the joint core in the shear resisting mechanism is not considered. The nonlinear finite element analysis using ABAQUS software has been employed in this study to numerically investigate the influence of different joint reinforcement configurations on joint performance. Four sets of beam-column connections with different joint stirrups configurations have been modeled for achieving this purpose, considering two validated experimentally tested beam-column connections as reference. This study reveals that achieving the codes minimum joint reinforcement ratio using both internal cross ties and outer stirrups instead of outer stirrups only is more efficient in terms of joint strength and deformation capacity which indicates that the contribution of the cross ties considering its shape and location in the shear strength resistance should be considered. It has been observed that both the joint strength and deformation capacity have been significantly improved with the use of two closed rectangular cross ties or one polygon cross tie within the joint region. Hence, those two layouts are considered as the most practical solutions in which the maximum spacing between the stirrups can be considerably increased without affecting the joint performance. The results also proved that the induced stress in the joint stirrups doesn't necessarily reach their yield strength even at the instant of joint failure. Hence, the yielding assumption for all layers of joint reinforcement in some analytical models and different international codes is unsafe and needs some revision.
Engineering Research Journal
Engineering Research Journal, Jun 1, 2019
Though they are naturally anisotropic and heterogeneous, the mechanical behavior of masonry walls... more Though they are naturally anisotropic and heterogeneous, the mechanical behavior of masonry walls in the micro modeling for the purpose of nonlinear analysis, can be simplified by adopting the homogenization technique. In this, the Cartesian coordinates coincide with the bed joint and in perpendicular (in the direction of the head joint); then, the wall is treated as an orthotropic material. In this paper, the development of a ten parameters failure criterion is presented; where the parameters are obtained from experimental tests. The tests of Page are used to show how the procedure of regression analysis can be performed for a better prediction of the wall strength. The obtained results show the effectiveness of the homogenization technique and the reliability of the proposed regression procedure in the development of the failure surface. The proposed failure criterion allows the use of continuum damage mechanics and the incremental approach for tension and compression regimes by inserting damage variables to the criterion. The proposed failure surface and preliminary results show the potential of modeling masonry under biaxial state of stress.
Journal of Structural Engineering & Applied Mechanics
The strut-and-tie method (STM) can serve as a tool for a safe design of concrete structures or me... more The strut-and-tie method (STM) can serve as a tool for a safe design of concrete structures or members. It aids to trace the flow of forces, appropriately lay-out the reinforcement, and safely predict the structure capacity. On the other hand, the linear elastic finite element can be utilized as an alternative in the development of the strut-and-tie models besides the load path method. In addition, the nonlinear finite element analysis assists in the optimization of the design results obtained from the STM. Hence, the two methods work well as companions in structural design. In order to demonstrate such understanding, different examples which include a deep beam with large opening and recess, continuous deep beams with and without openings, and beam ledges, have been utilized. In the STM solutions, the ACI 318-14 failure criteria have been adopted. In the nonlinear finite element analysis, material nonlinearity has been accounted for. The obtained solutions from the two methods, alo...
Journal of Structural Engineering & Applied Mechanics
For better strength prediction using strut-and-tie models (STM), it is essential to use reliable ... more For better strength prediction using strut-and-tie models (STM), it is essential to use reliable strength parameters of the model components; e.g., struts, ties, and nodes. Among all the elements of the STM, the strength of the bottle-shaped struts is not well quantified. The purpose of this study is to develop more accurate formulas for the calculation of the effectiveness factors for 2D bottle-shaped struts, that are unreinforced, reinforced with minimum reinforcement, and reinforced with sufficient transverse reinforcement. The nonlinear finite element analysis, with the aid of the software ABAQUS, has been utilized in this study, which has been verified against experimental tests. The study has been carried out for grades of concrete varying from 20 to 100MPa, and for bearing plate to width ratio varying from 0.1 to 0.9. The obtained formulas for the effectiveness factors of bottle-shaped struts are functions of the concrete strength, which is not the case with the ACI 318-19 pr...
Structural Concrete, 2004
Journal of Structural Engineering & Applied Mechanics
For better strength prediction using strut-and-tie models (STM), it is essential to use reliable ... more For better strength prediction using strut-and-tie models (STM), it is essential to use reliable strength parameters of the model components; e.g., struts, ties, and nodes. Among all the elements of the STM, the strength of the bottle-shaped struts is not well quantified. The purpose of this study is to develop more accurate formulas for the calculation of the effectiveness factors for 2D bottle-shaped struts, that are unreinforced, reinforced with minimum reinforcement, and reinforced with sufficient transverse reinforcement. The nonlinear finite element analysis, with the aid of the software ABAQUS, has been utilized in this study, which has been verified against experimental tests. The study has been carried out for grades of concrete varying from 20 to 100MPa, and for bearing plate to width ratio varying from 0.1 to 0.9. The obtained formulas for the effectiveness factors of bottle-shaped struts are functions of the concrete strength, which is not the case with the ACI 318-19 pr...
Proceedings of the 2015 International Conference on Mechatronics, Electronic, Industrial and Control Engineering, 2015
Reinforced concrete frames are one of most popular structures used in the world, but the research... more Reinforced concrete frames are one of most popular structures used in the world, but the research on their fire is at primary stage. In this thesis, the non-liner analysis of reinforced concrete frames at elevated temperature was analyzed by ANSYS, which included calculations and analysis of temperature field，structural deformation, and post-fire ultimate loadings, it was investigated in this paper with ANSYS ． The analysis results indicate that the reinforced concrete frame members undergo internal force redistribution under a fire, and the super position of constraint internal forces with external loads causes destroy in beams and columns. Finally, the fire-resistance design of concrete structures was also discussed.In this thesis, by IS0834 Standard temperature-time curve ． At the same time ， the temperature field, the deformation law at high temperatures are also put forward ． The temperature field is simulated using ANSYS,and the calculated results agree with test results ． In a one compartment fire, obvious deformation of structural occurs lead to internal forces changed during fire，and the thermal expansion of the heated beams and columns is the main agitator in a one compartment fire. The degree of redistribution of the moment of the end of column is larger than the end of beam. Fire location has more influences on the fire resistance of reinforced concrete frame because the part of the structure at ambient temperature exerts different restrictions on the heated part.In the end, several suggestions are presented on the applicable design method of reinforced concrete frame in the fire.
Structural Concrete, 2003
The beam–column joint is one of the important structural elements of reinforced concrete structur... more The beam–column joint is one of the important structural elements of reinforced concrete structures. It has been the subject of intensive research for the past four decades. To date, most of the design procedures of joints have been devoted to ordinary-strength concrete as implemented in the current international design codes. The use of high-strength concrete has become useful because of the advantages of member size limitation and higher structural capacity. However, its applicability is still limited because its behaviour, especially under combined stresses and shear, differs from ordinary-strength concrete in the presence of axial loading on the column. Consequently, the existing design guidelines are not completely applicable. In order to establish the salient features of the behaviour, namely modes of failure, deformational characteristics, strength parameters and strain development, an experimental programme was performed on beam–column joints under quasi-static monotonic loading. The influence of ...
Exploring the dual nature of computing education research.
Journal of Structural Engineering & Applied Mechanics, 2021
For better strength prediction using strut-and-tie models (STM), it is essential to use reliable ... more For better strength prediction using strut-and-tie models (STM), it is essential to use reliable strength parameters of the model components; e.g., struts, ties, and nodes. Among all the elements of the STM, the strength of the bottle-shaped struts is not well quantified. The purpose of this study is to develop more accurate formulas for the calculation of the effectiveness factors for 2D bottle-shaped struts, that are unreinforced, reinforced with minimum reinforcement, and reinforced with sufficient transverse reinforcement. The nonlinear finite element analysis, with the aid of the software ABAQUS, has been utilized in this study, which has been verified against experimental tests. The study has been carried out for grades of concrete varying from 20 to 100MPa, and for bearing plate to width ratio varying from 0.1 to 0.9. The obtained formulas for the effectiveness factors of bottle-shaped struts are functions of the concrete strength, which is not the case with the ACI 318-19 provisions. These formulas have been verified against experimental tests and have been compared with the ACI 318-19 provisions. The predictions based on these formulas are more accurate than those based on the ACI 318-19 provisions. Also, the results from these formulas are always on the safe side. On the other hand, the ACI 318-19 provisions lead to unsafe results in the case of high-strength concrete and very conservative results for the case of unreinforced struts from normal-strength concrete.
Performance based design has become essential in order to improve structure behavior and life cyc... more Performance based design has become essential in order to improve structure behavior and life cycle cost. The tool for achieving such a design in steel frames is the advanced analysis. With the advanced analysis the designer avoids the drawbacks of the K-factor design in addition to achieving more reliable and economic design. The only difficulty encountered in advanced analysis is the excessive computation effort; nevertheless, this problem has remarkably been eased in the practical advanced analysis. This presentation outlines the method of practical advanced analysis and it demonstrates the application of the method for the assessment of steel frame performance under fire and earthquakes. Under fire, the analysis results in predictions of the critical load factor, critical temperature, under which a frame may collapse, along with the fire duration and deformability of the frame. Under earthquakes the analysis achieves both "performance-based design" and "structure ...
Safety is the key objective in structural design; however, for economy design optimization become... more Safety is the key objective in structural design; however, for economy design optimization becomes an important issue. This paper looks at these two points which may seem to contradict, and tries to draw a line in order to help designers. The subject of this investigation is ledges in inverted-T beams. For safety, the strutand-tie model as a lower bound solution contributes to the development of safe design. The nonlinear finite element as an analytical tool helps to guide designers in deciding on the optimum performance of a given design. With two tools a designer can realize where a given design stands from safety and efficiency.
The relevant detailing of joint reinforcement plays a major role in ensuring adequate performance... more The relevant detailing of joint reinforcement plays a major role in ensuring adequate performance of reinforced concrete frames in terms of strength and ductility. The reinforcement detailing of joints with U-shaped bars in most common codes is achieved by providing a minimum stirrups reinforcement ratio and a maximum spacing between them; however, the contribution of the cross ties configuration within the joint core in the shear resisting mechanism is not considered. The nonlinear finite element analysis using ABAQUS software has been employed in this study to numerically investigate the influence of different joint reinforcement configurations on joint performance. Four sets of beam-column connections with different joint stirrups configurations have been modeled for achieving this purpose, considering two validated experimentally tested beam-column connections as reference. This study reveals that achieving the codes minimum joint reinforcement ratio using both internal cross ties and outer stirrups instead of outer stirrups only is more efficient in terms of joint strength and deformation capacity which indicates that the contribution of the cross ties considering its shape and location in the shear strength resistance should be considered. It has been observed that both the joint strength and deformation capacity have been significantly improved with the use of two closed rectangular cross ties or one polygon cross tie within the joint region. Hence, those two layouts are considered as the most practical solutions in which the maximum spacing between the stirrups can be considerably increased without affecting the joint performance. The results also proved that the induced stress in the joint stirrups doesn't necessarily reach their yield strength even at the instant of joint failure. Hence, the yielding assumption for all layers of joint reinforcement in some analytical models and different international codes is unsafe and needs some revision.
Engineering Research Journal
Engineering Research Journal, Jun 1, 2019
Though they are naturally anisotropic and heterogeneous, the mechanical behavior of masonry walls... more Though they are naturally anisotropic and heterogeneous, the mechanical behavior of masonry walls in the micro modeling for the purpose of nonlinear analysis, can be simplified by adopting the homogenization technique. In this, the Cartesian coordinates coincide with the bed joint and in perpendicular (in the direction of the head joint); then, the wall is treated as an orthotropic material. In this paper, the development of a ten parameters failure criterion is presented; where the parameters are obtained from experimental tests. The tests of Page are used to show how the procedure of regression analysis can be performed for a better prediction of the wall strength. The obtained results show the effectiveness of the homogenization technique and the reliability of the proposed regression procedure in the development of the failure surface. The proposed failure criterion allows the use of continuum damage mechanics and the incremental approach for tension and compression regimes by inserting damage variables to the criterion. The proposed failure surface and preliminary results show the potential of modeling masonry under biaxial state of stress.
Journal of Structural Engineering & Applied Mechanics
The strut-and-tie method (STM) can serve as a tool for a safe design of concrete structures or me... more The strut-and-tie method (STM) can serve as a tool for a safe design of concrete structures or members. It aids to trace the flow of forces, appropriately lay-out the reinforcement, and safely predict the structure capacity. On the other hand, the linear elastic finite element can be utilized as an alternative in the development of the strut-and-tie models besides the load path method. In addition, the nonlinear finite element analysis assists in the optimization of the design results obtained from the STM. Hence, the two methods work well as companions in structural design. In order to demonstrate such understanding, different examples which include a deep beam with large opening and recess, continuous deep beams with and without openings, and beam ledges, have been utilized. In the STM solutions, the ACI 318-14 failure criteria have been adopted. In the nonlinear finite element analysis, material nonlinearity has been accounted for. The obtained solutions from the two methods, alo...
Journal of Structural Engineering & Applied Mechanics
For better strength prediction using strut-and-tie models (STM), it is essential to use reliable ... more For better strength prediction using strut-and-tie models (STM), it is essential to use reliable strength parameters of the model components; e.g., struts, ties, and nodes. Among all the elements of the STM, the strength of the bottle-shaped struts is not well quantified. The purpose of this study is to develop more accurate formulas for the calculation of the effectiveness factors for 2D bottle-shaped struts, that are unreinforced, reinforced with minimum reinforcement, and reinforced with sufficient transverse reinforcement. The nonlinear finite element analysis, with the aid of the software ABAQUS, has been utilized in this study, which has been verified against experimental tests. The study has been carried out for grades of concrete varying from 20 to 100MPa, and for bearing plate to width ratio varying from 0.1 to 0.9. The obtained formulas for the effectiveness factors of bottle-shaped struts are functions of the concrete strength, which is not the case with the ACI 318-19 pr...
Structural Concrete, 2004
Journal of Structural Engineering & Applied Mechanics
For better strength prediction using strut-and-tie models (STM), it is essential to use reliable ... more For better strength prediction using strut-and-tie models (STM), it is essential to use reliable strength parameters of the model components; e.g., struts, ties, and nodes. Among all the elements of the STM, the strength of the bottle-shaped struts is not well quantified. The purpose of this study is to develop more accurate formulas for the calculation of the effectiveness factors for 2D bottle-shaped struts, that are unreinforced, reinforced with minimum reinforcement, and reinforced with sufficient transverse reinforcement. The nonlinear finite element analysis, with the aid of the software ABAQUS, has been utilized in this study, which has been verified against experimental tests. The study has been carried out for grades of concrete varying from 20 to 100MPa, and for bearing plate to width ratio varying from 0.1 to 0.9. The obtained formulas for the effectiveness factors of bottle-shaped struts are functions of the concrete strength, which is not the case with the ACI 318-19 pr...
Proceedings of the 2015 International Conference on Mechatronics, Electronic, Industrial and Control Engineering, 2015
Reinforced concrete frames are one of most popular structures used in the world, but the research... more Reinforced concrete frames are one of most popular structures used in the world, but the research on their fire is at primary stage. In this thesis, the non-liner analysis of reinforced concrete frames at elevated temperature was analyzed by ANSYS, which included calculations and analysis of temperature field，structural deformation, and post-fire ultimate loadings, it was investigated in this paper with ANSYS ． The analysis results indicate that the reinforced concrete frame members undergo internal force redistribution under a fire, and the super position of constraint internal forces with external loads causes destroy in beams and columns. Finally, the fire-resistance design of concrete structures was also discussed.In this thesis, by IS0834 Standard temperature-time curve ． At the same time ， the temperature field, the deformation law at high temperatures are also put forward ． The temperature field is simulated using ANSYS,and the calculated results agree with test results ． In a one compartment fire, obvious deformation of structural occurs lead to internal forces changed during fire，and the thermal expansion of the heated beams and columns is the main agitator in a one compartment fire. The degree of redistribution of the moment of the end of column is larger than the end of beam. Fire location has more influences on the fire resistance of reinforced concrete frame because the part of the structure at ambient temperature exerts different restrictions on the heated part.In the end, several suggestions are presented on the applicable design method of reinforced concrete frame in the fire.
Structural Concrete, 2003
The beam–column joint is one of the important structural elements of reinforced concrete structur... more The beam–column joint is one of the important structural elements of reinforced concrete structures. It has been the subject of intensive research for the past four decades. To date, most of the design procedures of joints have been devoted to ordinary-strength concrete as implemented in the current international design codes. The use of high-strength concrete has become useful because of the advantages of member size limitation and higher structural capacity. However, its applicability is still limited because its behaviour, especially under combined stresses and shear, differs from ordinary-strength concrete in the presence of axial loading on the column. Consequently, the existing design guidelines are not completely applicable. In order to establish the salient features of the behaviour, namely modes of failure, deformational characteristics, strength parameters and strain development, an experimental programme was performed on beam–column joints under quasi-static monotonic loading. The influence of ...
Exploring the dual nature of computing education research.
Journal of Structural Engineering & Applied Mechanics, 2021
For better strength prediction using strut-and-tie models (STM), it is essential to use reliable ... more For better strength prediction using strut-and-tie models (STM), it is essential to use reliable strength parameters of the model components; e.g., struts, ties, and nodes. Among all the elements of the STM, the strength of the bottle-shaped struts is not well quantified. The purpose of this study is to develop more accurate formulas for the calculation of the effectiveness factors for 2D bottle-shaped struts, that are unreinforced, reinforced with minimum reinforcement, and reinforced with sufficient transverse reinforcement. The nonlinear finite element analysis, with the aid of the software ABAQUS, has been utilized in this study, which has been verified against experimental tests. The study has been carried out for grades of concrete varying from 20 to 100MPa, and for bearing plate to width ratio varying from 0.1 to 0.9. The obtained formulas for the effectiveness factors of bottle-shaped struts are functions of the concrete strength, which is not the case with the ACI 318-19 provisions. These formulas have been verified against experimental tests and have been compared with the ACI 318-19 provisions. The predictions based on these formulas are more accurate than those based on the ACI 318-19 provisions. Also, the results from these formulas are always on the safe side. On the other hand, the ACI 318-19 provisions lead to unsafe results in the case of high-strength concrete and very conservative results for the case of unreinforced struts from normal-strength concrete.
Performance based design has become essential in order to improve structure behavior and life cyc... more Performance based design has become essential in order to improve structure behavior and life cycle cost. The tool for achieving such a design in steel frames is the advanced analysis. With the advanced analysis the designer avoids the drawbacks of the K-factor design in addition to achieving more reliable and economic design. The only difficulty encountered in advanced analysis is the excessive computation effort; nevertheless, this problem has remarkably been eased in the practical advanced analysis. This presentation outlines the method of practical advanced analysis and it demonstrates the application of the method for the assessment of steel frame performance under fire and earthquakes. Under fire, the analysis results in predictions of the critical load factor, critical temperature, under which a frame may collapse, along with the fire duration and deformability of the frame. Under earthquakes the analysis achieves both "performance-based design" and "structure ...
Safety is the key objective in structural design; however, for economy design optimization become... more Safety is the key objective in structural design; however, for economy design optimization becomes an important issue. This paper looks at these two points which may seem to contradict, and tries to draw a line in order to help designers. The subject of this investigation is ledges in inverted-T beams. For safety, the strutand-tie model as a lower bound solution contributes to the development of safe design. The nonlinear finite element as an analytical tool helps to guide designers in deciding on the optimum performance of a given design. With two tools a designer can realize where a given design stands from safety and efficiency.