This paper presents an experimental and numerical investigation on the behavior and failure mecha... more This paper presents an experimental and numerical investigation on the behavior and failure mechanisms of unreinforced multi-leaf masonry walls. The main objective of this study is to explore the propagation of cracking, ultimate load, and deformation characteristics of different typologies of three-leaf walls commonly found in historic masonry. Axial compression tests on scaled three-leaf wallettes built of limestone units and lime-based mortar, as well as experiments on constituent materials for each leaf, were carried out. The main results obtained from the experimental tests are the mechanical characteristics, stress–strain curves, stress distributions in multi-leaf masonry walls. The research findings elucidate a strong correlation between the bearing capacity of multi-leaf walls and the thickness ratio of the inner-core layer to the external layers. This relationship underscores the critical significance of the inner-core layer in efficiently carrying the applied vertical loads. Furthermore, the extent to which the inner-core layer actively contributes to load-bearing is contingent upon the interconnectivity among the three layers. Walls with keyed collar joints have a higher strength and stiffness than the walls without transverse tying, with the strength being comparatively higher by about 9–13 %. This clarifies the contribution of the inner core layer and that of the two outer layers in resisting vertical loads and enhancing the overall composite behavior of the wall. Finally, these results allow for validating non-linear numerical procedures based on two-dimensional plane strain modelling along wall thickness and a simplified micro-modelling approach, which prove to be adequate tools for detailed modelling of masonry components of similar nature.
In order to correctly define the pathology of multiple-leaf stonemasonry walls and determine the ... more In order to correctly define the pathology of multiple-leaf stonemasonry walls and determine the appropriate interventions for its conservation and preservation, comprehensive studies on its building materials should be carried out since the overall behaviour of masonry structures is highly dependent on the characterization of its construction materials. Consequently, an interdisciplinary procedure for construction material characterization used in multiple-leaf stone-masonry walls in Egypt has been implemented to enrich documentation, conservation and restoration issues of this type of wall. The research methodology integrates experimental data obtained through on-site sampling, conducted tests and analyses, historical information, and field survey observations. The fundamental physical and mechanical properties of the masonry elements were examined by incorporating stone blocks, mortars and core-infill materials. The mineralogical composition and interlocking textures of the colle...
Roller compacted concrete is widely known for its relatively low cost and short construction time... more Roller compacted concrete is widely known for its relatively low cost and short construction time. RCC gravity dams require high foundation (rock) bearing capacity. Research has been carried out which proposes to rationalise the amount of material in the dam by creating inner voids, in the shape of bubbles. As a key requirement, the introduced bubbles should not affect the dam stability and safety. The bubbles will reduce the self-weight of the dam and minimise the required rock bearing capacity. A system of pipes connecting the bubbles ensures drainage of the bubbles. The proposed dam would save about 12% of the required concrete volume. Different construction methods were studied and the best alternative is the use of precast hollow boxes. This decreases RCC placement in the dam by 32.5%. The objective is to speed the construction process and minimise the risk of the heat of hydration.
In order to correctly define the pathology of multiple-leaf stonemasonry walls and determine the ... more In order to correctly define the pathology of multiple-leaf stonemasonry walls and determine the appropriate interventions for its conservation and preservation, comprehensive studies on its building materials should be carried out since the overall behaviour of masonry structures is highly dependent on the characterization of its construction materials. Consequently, an interdisciplinary procedure for construction material characterization used in multiple-leaf stone-masonry walls in Egypt has been implemented to enrich documentation, conservation and restoration issues of this type of wall. The research methodology integrates experimental data obtained through on-site sampling, conducted tests and analyses, historical information, and field survey observations. The fundamental physical and mechanical properties of the masonry elements were examined by incorporating stone blocks, mortars and core-infill materials. The mineralogical composition and interlocking textures of the colle...
Multi-leaf stone masonry walls are a typical construction technique in architectural heritage in ... more Multi-leaf stone masonry walls are a typical construction technique in architectural heritage in Egypt. The assessment, modeling, and strengthening of historic masonry walls of multi-leaf systems essentially require suitable knowledge of their construction technology, typology, geometrical characteristics, and the properties of their components. Within the current research project, a comprehensive structural survey of multiple-leaf walls of medieval historic buildings in Cairo was performed. The observation and statistical analyses allowed characterization of the transversal section of the surveyed walls, as well as examination and identification of the construction materials and techniques. The slenderness ratios of this type of wall, its blocks’ dimensions, the utilized connectivity between the inner and outer leaves, and leaves ratio were also investigated. Three construction hypotheses of multiple-leaf stone masonry walls are presented considering weak, thick, and monolithic cor...
In order to correctly define the pathology of multiple-leaf stonemasonry walls and determine the ... more In order to correctly define the pathology of multiple-leaf stonemasonry walls and determine the appropriate interventions for its conservation and preservation, comprehensive studies on its building materials should be carried out since the overall behaviour of masonry structures is highly dependent on the characterization of its construction materials. Consequently, an interdisciplinary procedure for construction material characterization used in multiple-leaf stone-masonry walls in Egypt has been implemented to enrich documentation, conservation and restoration issues of this type of wall. The research methodology integrates experimental data obtained through on-site sampling, conducted tests and analyses, historical information, and field survey observations. The fundamental physical and mechanical properties of the masonry elements were examined by incorporating stone blocks, mortars and core-infill materials. The mineralogical composition and interlocking textures of the collected samples were investigated utilizing a large range of complementary investigation and analysis techniques, including polarizing microscopy, X-ray diffraction (XRD), thermal analysis (TG/DTA), and environmental scanning electron microscope (ESEM) attached to an EDX unit. Through the results thus obtained, a complete characterization of the mineralogical composition; physical–mechanical, chemical, and thermal properties; and the interlocking textures of the construction materials of both the outer and inner-core layers was performed. The outer leaves of the majority of the multiple-leaf stone-masonry walls in medieval architectural heritage were mainly built of well-dressed limestone blocks with nearly uniform dimensions, while the inner-core layer was usually built of stone-rubble infill with bending lime-based mortar. The uniaxial compressive strengths of core infill (corresponding to the inner core layer) and lime-based mortar of the embedded joints are shown to be 85 and 92.5% lower than the limestone units of the outer layer, respectively. Moreover, experimental observations indicate that the inner core layer exhibits the highest porosity values; consequently, deteriorated, loose and cohesionless core infill could greatly affect the durability and thermal resistivity of this kind of wall. The results provide scientific support for investigating the overall structural behaviour of this type of walls and for decision-making in future conservation and restoration strategies.
The old irrigation hydraulic structures along the Nile and its main branches face the problems of... more The old irrigation hydraulic structures along the Nile and its main branches face the problems of operation, aging, ill maintenance and the desire to extend its lifetime. Economically, building a new one is not feasible. Furthermore, the operation of the irrigation system changed dramatically after building the High Aswan Dam and new design codes replaced the old design methods. Upgrading and enhancing old masonry hydraulic structures in Egypt is an extreme necessity and traditional solutions are not compatible with the operational requirements. For a reason or another, several structures such as Assuit and Zefta barrages have been remodeled. Upgrading and renovating constitute several studies and structural solutions that are not commonly available and has to be taken as a case by case matter, and the literature does not support such cases well.
This paper presents several upgrading solutions for an old regulator, where not all methods are convenient. A study of the different methods is presented and analyzed.
The major load acting on long span bridges is aerodynamic forces; the major part of aerodynamic f... more The major load acting on long span bridges is aerodynamic forces; the major part of aerodynamic forces generated by bridge deck. The present study discusses minimizing aerodynamic forces by modifying deck shape. Six deck cross sections were proposed. The criteria of proposing deck cross section were to smooth deck edges and choose a most streamlined shape. Three Elliptical shapes and three streamlined box section were proposed. Computational Fluid Dynamic (CFD), an effective numerical tool used for simulating air flow around wings and bridge decks, used for the analysis of proposed deck; CFD was verified in literature. The generated aerodynamic forces were compared with Sutong Bridge. The elliptical shape generated lower aerodynamic forces than others deck sections that prove, as deck shape get smoother aerodynamic forces generated by the deck reduce.
Suspension bridges are longest span structures, however, the major problem of those structures ar... more Suspension bridges are longest span structures, however, the major problem of those structures are its low lateral stiffness. The suspension cable is the major element of such bridges; moreover, it is the key of the analysis. The challenge in suspension cable analysis is the material and geometrical
Live Load Distribution Factors (LLDF) method is widely used to simplify bridge deck analysis. In ... more Live Load Distribution Factors (LLDF) method is widely used to simplify bridge deck analysis. In this method, the superstructure is modeled as a single spine. The straining actions obtained are then distributed among the different girders using the LLDFs. Finite element modeling is used for the analysis of several concrete bridges of slab-on-girder and box-girder types. The modeling details are verified by comparing deflections with site measurements. Over 6000 cases were analyzed to calculate LLDF for truck loading specified by the Euro Code EN 1991 and Egyptian Code ECP 201. Non-linear regression analysis is applied on the obtained results to calibrate the parameters of LLDF equations. LLDF equations suitable for use with ECP 201 and EN 1991 truck loading for straight and skew concrete bridges of slab-on-girder and box-girder types are proposed. [Ahmed M. Saleh, Mohamed Rabie and Ezz-El-Din Kamel.
Suspension bridges are longest span structures, however, the major problem of those structures ar... more Suspension bridges are longest span structures, however, the major problem of those structures are its stability under wind loads. The stability of those bridges depends majorly on aerodynamic forces and structural supporting system; this study worked on those two major axes. Aerodynamic axis was to minimize aerodynamic forces by optimizing deck shape. Computational fluid dynamic (CFD) is an effective numerical tool for simulating flow around bridge deck, which was verified in the literature. six deck cross sections were studied – three elliptical deck shapes and three closed trusses-; their generated aerodynamic forces were compared with forces acting on Sutong Bridge and the best one was modelled as unsteady- state model for calculating flutter derivatives. The elliptical deck shape is found to generate the least static pressure and aerodynamic forces relative to the box and closed truss shapes; that proves, as deck shape get smoother aerodynamic forces generated by the deck reduces Structural axis was to improve the stability of cable supporting system. A combination of three-dimensional suspension cable and cable-stay systems studied. Catenary theory was improved for determining three-dimensional suspension cable profile. Three models suspension bridge and eight models cable-stayed suspension cable were studied. The use of three-dimensional suspension cable improved critical wind speed..
This paper presents an experimental and numerical investigation on the behavior and failure mecha... more This paper presents an experimental and numerical investigation on the behavior and failure mechanisms of unreinforced multi-leaf masonry walls. The main objective of this study is to explore the propagation of cracking, ultimate load, and deformation characteristics of different typologies of three-leaf walls commonly found in historic masonry. Axial compression tests on scaled three-leaf wallettes built of limestone units and lime-based mortar, as well as experiments on constituent materials for each leaf, were carried out. The main results obtained from the experimental tests are the mechanical characteristics, stress–strain curves, stress distributions in multi-leaf masonry walls. The research findings elucidate a strong correlation between the bearing capacity of multi-leaf walls and the thickness ratio of the inner-core layer to the external layers. This relationship underscores the critical significance of the inner-core layer in efficiently carrying the applied vertical loads. Furthermore, the extent to which the inner-core layer actively contributes to load-bearing is contingent upon the interconnectivity among the three layers. Walls with keyed collar joints have a higher strength and stiffness than the walls without transverse tying, with the strength being comparatively higher by about 9–13 %. This clarifies the contribution of the inner core layer and that of the two outer layers in resisting vertical loads and enhancing the overall composite behavior of the wall. Finally, these results allow for validating non-linear numerical procedures based on two-dimensional plane strain modelling along wall thickness and a simplified micro-modelling approach, which prove to be adequate tools for detailed modelling of masonry components of similar nature.
In order to correctly define the pathology of multiple-leaf stonemasonry walls and determine the ... more In order to correctly define the pathology of multiple-leaf stonemasonry walls and determine the appropriate interventions for its conservation and preservation, comprehensive studies on its building materials should be carried out since the overall behaviour of masonry structures is highly dependent on the characterization of its construction materials. Consequently, an interdisciplinary procedure for construction material characterization used in multiple-leaf stone-masonry walls in Egypt has been implemented to enrich documentation, conservation and restoration issues of this type of wall. The research methodology integrates experimental data obtained through on-site sampling, conducted tests and analyses, historical information, and field survey observations. The fundamental physical and mechanical properties of the masonry elements were examined by incorporating stone blocks, mortars and core-infill materials. The mineralogical composition and interlocking textures of the colle...
Roller compacted concrete is widely known for its relatively low cost and short construction time... more Roller compacted concrete is widely known for its relatively low cost and short construction time. RCC gravity dams require high foundation (rock) bearing capacity. Research has been carried out which proposes to rationalise the amount of material in the dam by creating inner voids, in the shape of bubbles. As a key requirement, the introduced bubbles should not affect the dam stability and safety. The bubbles will reduce the self-weight of the dam and minimise the required rock bearing capacity. A system of pipes connecting the bubbles ensures drainage of the bubbles. The proposed dam would save about 12% of the required concrete volume. Different construction methods were studied and the best alternative is the use of precast hollow boxes. This decreases RCC placement in the dam by 32.5%. The objective is to speed the construction process and minimise the risk of the heat of hydration.
In order to correctly define the pathology of multiple-leaf stonemasonry walls and determine the ... more In order to correctly define the pathology of multiple-leaf stonemasonry walls and determine the appropriate interventions for its conservation and preservation, comprehensive studies on its building materials should be carried out since the overall behaviour of masonry structures is highly dependent on the characterization of its construction materials. Consequently, an interdisciplinary procedure for construction material characterization used in multiple-leaf stone-masonry walls in Egypt has been implemented to enrich documentation, conservation and restoration issues of this type of wall. The research methodology integrates experimental data obtained through on-site sampling, conducted tests and analyses, historical information, and field survey observations. The fundamental physical and mechanical properties of the masonry elements were examined by incorporating stone blocks, mortars and core-infill materials. The mineralogical composition and interlocking textures of the colle...
Multi-leaf stone masonry walls are a typical construction technique in architectural heritage in ... more Multi-leaf stone masonry walls are a typical construction technique in architectural heritage in Egypt. The assessment, modeling, and strengthening of historic masonry walls of multi-leaf systems essentially require suitable knowledge of their construction technology, typology, geometrical characteristics, and the properties of their components. Within the current research project, a comprehensive structural survey of multiple-leaf walls of medieval historic buildings in Cairo was performed. The observation and statistical analyses allowed characterization of the transversal section of the surveyed walls, as well as examination and identification of the construction materials and techniques. The slenderness ratios of this type of wall, its blocks’ dimensions, the utilized connectivity between the inner and outer leaves, and leaves ratio were also investigated. Three construction hypotheses of multiple-leaf stone masonry walls are presented considering weak, thick, and monolithic cor...
In order to correctly define the pathology of multiple-leaf stonemasonry walls and determine the ... more In order to correctly define the pathology of multiple-leaf stonemasonry walls and determine the appropriate interventions for its conservation and preservation, comprehensive studies on its building materials should be carried out since the overall behaviour of masonry structures is highly dependent on the characterization of its construction materials. Consequently, an interdisciplinary procedure for construction material characterization used in multiple-leaf stone-masonry walls in Egypt has been implemented to enrich documentation, conservation and restoration issues of this type of wall. The research methodology integrates experimental data obtained through on-site sampling, conducted tests and analyses, historical information, and field survey observations. The fundamental physical and mechanical properties of the masonry elements were examined by incorporating stone blocks, mortars and core-infill materials. The mineralogical composition and interlocking textures of the collected samples were investigated utilizing a large range of complementary investigation and analysis techniques, including polarizing microscopy, X-ray diffraction (XRD), thermal analysis (TG/DTA), and environmental scanning electron microscope (ESEM) attached to an EDX unit. Through the results thus obtained, a complete characterization of the mineralogical composition; physical–mechanical, chemical, and thermal properties; and the interlocking textures of the construction materials of both the outer and inner-core layers was performed. The outer leaves of the majority of the multiple-leaf stone-masonry walls in medieval architectural heritage were mainly built of well-dressed limestone blocks with nearly uniform dimensions, while the inner-core layer was usually built of stone-rubble infill with bending lime-based mortar. The uniaxial compressive strengths of core infill (corresponding to the inner core layer) and lime-based mortar of the embedded joints are shown to be 85 and 92.5% lower than the limestone units of the outer layer, respectively. Moreover, experimental observations indicate that the inner core layer exhibits the highest porosity values; consequently, deteriorated, loose and cohesionless core infill could greatly affect the durability and thermal resistivity of this kind of wall. The results provide scientific support for investigating the overall structural behaviour of this type of walls and for decision-making in future conservation and restoration strategies.
The old irrigation hydraulic structures along the Nile and its main branches face the problems of... more The old irrigation hydraulic structures along the Nile and its main branches face the problems of operation, aging, ill maintenance and the desire to extend its lifetime. Economically, building a new one is not feasible. Furthermore, the operation of the irrigation system changed dramatically after building the High Aswan Dam and new design codes replaced the old design methods. Upgrading and enhancing old masonry hydraulic structures in Egypt is an extreme necessity and traditional solutions are not compatible with the operational requirements. For a reason or another, several structures such as Assuit and Zefta barrages have been remodeled. Upgrading and renovating constitute several studies and structural solutions that are not commonly available and has to be taken as a case by case matter, and the literature does not support such cases well.
This paper presents several upgrading solutions for an old regulator, where not all methods are convenient. A study of the different methods is presented and analyzed.
The major load acting on long span bridges is aerodynamic forces; the major part of aerodynamic f... more The major load acting on long span bridges is aerodynamic forces; the major part of aerodynamic forces generated by bridge deck. The present study discusses minimizing aerodynamic forces by modifying deck shape. Six deck cross sections were proposed. The criteria of proposing deck cross section were to smooth deck edges and choose a most streamlined shape. Three Elliptical shapes and three streamlined box section were proposed. Computational Fluid Dynamic (CFD), an effective numerical tool used for simulating air flow around wings and bridge decks, used for the analysis of proposed deck; CFD was verified in literature. The generated aerodynamic forces were compared with Sutong Bridge. The elliptical shape generated lower aerodynamic forces than others deck sections that prove, as deck shape get smoother aerodynamic forces generated by the deck reduce.
Suspension bridges are longest span structures, however, the major problem of those structures ar... more Suspension bridges are longest span structures, however, the major problem of those structures are its low lateral stiffness. The suspension cable is the major element of such bridges; moreover, it is the key of the analysis. The challenge in suspension cable analysis is the material and geometrical
Live Load Distribution Factors (LLDF) method is widely used to simplify bridge deck analysis. In ... more Live Load Distribution Factors (LLDF) method is widely used to simplify bridge deck analysis. In this method, the superstructure is modeled as a single spine. The straining actions obtained are then distributed among the different girders using the LLDFs. Finite element modeling is used for the analysis of several concrete bridges of slab-on-girder and box-girder types. The modeling details are verified by comparing deflections with site measurements. Over 6000 cases were analyzed to calculate LLDF for truck loading specified by the Euro Code EN 1991 and Egyptian Code ECP 201. Non-linear regression analysis is applied on the obtained results to calibrate the parameters of LLDF equations. LLDF equations suitable for use with ECP 201 and EN 1991 truck loading for straight and skew concrete bridges of slab-on-girder and box-girder types are proposed. [Ahmed M. Saleh, Mohamed Rabie and Ezz-El-Din Kamel.
Suspension bridges are longest span structures, however, the major problem of those structures ar... more Suspension bridges are longest span structures, however, the major problem of those structures are its stability under wind loads. The stability of those bridges depends majorly on aerodynamic forces and structural supporting system; this study worked on those two major axes. Aerodynamic axis was to minimize aerodynamic forces by optimizing deck shape. Computational fluid dynamic (CFD) is an effective numerical tool for simulating flow around bridge deck, which was verified in the literature. six deck cross sections were studied – three elliptical deck shapes and three closed trusses-; their generated aerodynamic forces were compared with forces acting on Sutong Bridge and the best one was modelled as unsteady- state model for calculating flutter derivatives. The elliptical deck shape is found to generate the least static pressure and aerodynamic forces relative to the box and closed truss shapes; that proves, as deck shape get smoother aerodynamic forces generated by the deck reduces Structural axis was to improve the stability of cable supporting system. A combination of three-dimensional suspension cable and cable-stay systems studied. Catenary theory was improved for determining three-dimensional suspension cable profile. Three models suspension bridge and eight models cable-stayed suspension cable were studied. The use of three-dimensional suspension cable improved critical wind speed..
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This paper presents several upgrading solutions for an old regulator, where not all methods are convenient. A study of the different methods is presented and analyzed.
method, the superstructure is modeled as a single spine. The straining actions obtained are then distributed among
the different girders using the LLDFs. Finite element modeling is used for the analysis of several concrete bridges of
slab-on-girder and box-girder types. The modeling details are verified by comparing deflections with site
measurements. Over 6000 cases were analyzed to calculate LLDF for truck loading specified by the Euro Code EN
1991 and Egyptian Code ECP 201. Non-linear regression analysis is applied on the obtained results to calibrate the
parameters of LLDF equations. LLDF equations suitable for use with ECP 201 and EN 1991 truck loading for
straight and skew concrete bridges of slab-on-girder and box-girder types are proposed.
[Ahmed M. Saleh, Mohamed Rabie and Ezz-El-Din Kamel.
Aerodynamic axis was to minimize aerodynamic forces by optimizing deck shape. Computational fluid dynamic (CFD) is an effective numerical tool for simulating flow around bridge deck, which was verified in the literature. six deck cross sections were studied – three elliptical deck shapes and three closed trusses-; their generated aerodynamic forces were compared with forces acting on Sutong Bridge and the best one was modelled as unsteady- state model for calculating flutter derivatives. The elliptical deck shape is found to generate the least static pressure and aerodynamic forces relative to the box and closed truss shapes; that proves, as deck shape get smoother aerodynamic forces generated by the deck reduces
Structural axis was to improve the stability of cable supporting system. A combination of three-dimensional suspension cable and cable-stay systems studied. Catenary theory was improved for determining three-dimensional suspension cable profile. Three models suspension bridge and eight models cable-stayed suspension cable were studied. The use of three-dimensional suspension cable improved critical wind speed..
This paper presents several upgrading solutions for an old regulator, where not all methods are convenient. A study of the different methods is presented and analyzed.
method, the superstructure is modeled as a single spine. The straining actions obtained are then distributed among
the different girders using the LLDFs. Finite element modeling is used for the analysis of several concrete bridges of
slab-on-girder and box-girder types. The modeling details are verified by comparing deflections with site
measurements. Over 6000 cases were analyzed to calculate LLDF for truck loading specified by the Euro Code EN
1991 and Egyptian Code ECP 201. Non-linear regression analysis is applied on the obtained results to calibrate the
parameters of LLDF equations. LLDF equations suitable for use with ECP 201 and EN 1991 truck loading for
straight and skew concrete bridges of slab-on-girder and box-girder types are proposed.
[Ahmed M. Saleh, Mohamed Rabie and Ezz-El-Din Kamel.
Aerodynamic axis was to minimize aerodynamic forces by optimizing deck shape. Computational fluid dynamic (CFD) is an effective numerical tool for simulating flow around bridge deck, which was verified in the literature. six deck cross sections were studied – three elliptical deck shapes and three closed trusses-; their generated aerodynamic forces were compared with forces acting on Sutong Bridge and the best one was modelled as unsteady- state model for calculating flutter derivatives. The elliptical deck shape is found to generate the least static pressure and aerodynamic forces relative to the box and closed truss shapes; that proves, as deck shape get smoother aerodynamic forces generated by the deck reduces
Structural axis was to improve the stability of cable supporting system. A combination of three-dimensional suspension cable and cable-stay systems studied. Catenary theory was improved for determining three-dimensional suspension cable profile. Three models suspension bridge and eight models cable-stayed suspension cable were studied. The use of three-dimensional suspension cable improved critical wind speed..