Journal of Structural Engineering-asce, Dec 1, 2019
AbstractA considerable amount of research studies have demonstrated the capability of metallic sa... more AbstractA considerable amount of research studies have demonstrated the capability of metallic sandwich panels in dissipating blast loading energy. Metallic sandwich panels dissipate blast energy t...
Journal of Structural Engineering-asce, Dec 1, 2020
AbstractIn typical wall load-bearing reinforced-masonry (RM) buildings, the lateral and vertical ... more AbstractIn typical wall load-bearing reinforced-masonry (RM) buildings, the lateral and vertical forces are resisted by rectangular shear walls. Thus, the walls are subjected to high vertical force...
Journal of Structural Engineering-asce, Apr 1, 2020
AbstractReinforced masonry buildings typically have a load-bearing wall structural system. Thus, ... more AbstractReinforced masonry buildings typically have a load-bearing wall structural system. Thus, the reinforced masonry shear walls must be capable of resisting both vertical forces from gravity lo...
Shear wall system is a common seismic force resisting system that is used for both reinforced mas... more Shear wall system is a common seismic force resisting system that is used for both reinforced masonry (RM) and reinforced concrete (RC) buildings. RM shear walls can provide a considerable level of ductility like RC walls, especially for walls with boundary elements. The latest provisions of the Canadian Standard for Masonry allowed a higher level of ductility for RM shear walls based on their ductile response. This paper aims to estimate the quantities of construction materials required for RM shear walls compared to those of RC walls. Three multistorey RM shear wall buildings with different heights located in three different cities in Canada were selected. 5-, 10-, and 15-storey buildings were located in Toronto, Montreal, and Vancouver cities which represent three different levels of seismic hazard. For each building's height and location, the RM shear walls were designed with the level of ductility that results in the least construction material quantities. The analysis and design procedures were repeated for each case when RC material was used. The amount of construction materials used for the shear walls of each building was evaluated for both RM and RC cases and they were compared. Moreover, the cost of labour and temporary works for RM and RC shear walls was estimated and compared. The comparisons showed that RM shear wall construction can be as economic as the RC one for different walls' ductility levels.
Confining existing concrete and masonry columns by Carbon Fiber Reinforced Polymers (CFRP) is a b... more Confining existing concrete and masonry columns by Carbon Fiber Reinforced Polymers (CFRP) is a beneficial method for enhancing the column axial capacity and ductility. This paper presents an experimental investigation of the CFRP confinement influence on the uniaxial compression stress-strain behavior of concrete block masonry columns. Scaled fully grouted concrete block masonry columns, with a square cross section, were confined by continuous CFRP jackets and tested under concentric axial loading up to failure. The results indicate that CFRP enhances the ultimate axial strain and the axial load capacity by up to 281% and 79%, respectively compared to unreinforced columns. In this study, the effect of corner radius and the thickness of CFRP jackets are investigated. Special attention was also given to the effective tensile strain in the CFRP jackets. Finally, the CNR-DT 200 R1 confinement model, the only guide addressing strengthening masonry columns with external FRP composites, was assessed and refined equation is proposed.
Fiber optic sensors have been increasingly utilized in structural health monitoring of large-scal... more Fiber optic sensors have been increasingly utilized in structural health monitoring of large-scale civil structures. Bare fiber sensors are quite brittle, and therefore, their installation and embedment in reinforced concrete elements can be challenging, particularly when using uncommon materials as internal reinforcements in concrete. In the present study, a fiber optic strain sensor is preinstalled on a supplemental bar of adequate length and appropriate diameter. The sensor is attached to a glass fiber-reinforced polymer (GFRP) reinforcing bar in concrete flexural element. Performance under static-loading conditions has been evaluated, and the results have shown potential toward applying the technique to large-scale structures. Another objective of the present study is to develop a numerical model that represents the interaction between the concrete, the reinforcement steel, and the supplemental GFRP rebar, which has the sensor mounted on. The model is calibrated using experimental results. The model can be used to investigate varying parameters including material properties (e.g., compressive strength of concrete), geometrical data (e.g., the length of the supplemental rebar), and loading and boundary conditions, consequently eliminating the need to perform a large number of full-scale costly experiments. The developed model exhibited nearly identical behavior to the experiments after calibration. The study shows that the performance of the present sensing system is primarily affected by the relative sizes of the main and supplemental bars.
Abstract The concept of resilience is gaining increased attention in disaster management due to t... more Abstract The concept of resilience is gaining increased attention in disaster management due to the recent awareness of the need to reduce the detrimental post-event effects of natural disasters, e.g., earthquakes. Resilience is a practical concept that includes pre-event (preparedness and mitigation) and post-event (response and recovery) activities. Quantitative resilience assessment approaches are needed to compare the available mitigation strategies to decide on the most suitable strategy and provide better support for decision-making procedures. In this study, a methodology for quantifying the seismic resilience of reinforced masonry shear wall (RMSW) buildings with end-confined masonry boundary elements is implemented. The uncertainties associated with structural and non-structural losses and estimated recovery time uncertainties are considered while quantifying the resilience index of RMSW buildings. The archetype buildings studied have 8-, 10-, and 12-storey heights and are located in Vancouver, representing a high seismic zone in Canada. First, a numerical model was developed using OpenSees to derive the fragility surface for the studied archetypes subjected to bi-directional horizontal excitation. Second, a Monte Carlo simulation was performed to quantify the resilience index of each archetype considering the above-mentioned uncertainties. The results prove the robustness of ductile RMSW buildings having end-confined MBEs in mitigating the losses associated with disaster events. Additionally, the findings provide comprehensive and valuable information for earthquake mitigation measures and disaster risk reduction programmes.
The concept of seismic resilience plays an important role in seismic assessment of structures as ... more The concept of seismic resilience plays an important role in seismic assessment of structures as it assesses the capability of a system to withstand an unwanted event, such as earthquakes, by estimating the losses and determining the system's functionality and sustainability during and after such event. In this study, a framework was utilized to assess the seismic resilience of Reinforced Masonry Shear Wall (RMSW) buildings as well as studying the impact of incorporating Masonry Boundary Elements (MBEs) at the ends of RMSW. To achieve this goal, a ten-story RMSW building was numerically modelled in OpenSees to assess the seismic performance and resilience of the system when adding confined MBEs. The selected building is located in Montreal, Canada, and initially designed to be built having rectangular walls. Subsequently, the walls were redesigned to integrate MBEs at their outermost fibre to help increase the ductility and strength of the RMSWs. A full 3D wide-column macro-modelling approach was used to simulate the dynamic response of the archetype building. Validation of the modelling approach was done against available experimental tests as an initial step to ensure the robustness of the model in predicting the inelastic response of the building. Subsequently, the models were analyzed against multiple ground motion records using Incremental Dynamic Analysis to identify the initiation of collapse alongside developing the fragility curves of the building. The system-level seismic performance of the building was assessed after incorporating MBEs. The resilience of the building was assessed using the developed fragility functions, and a comparison was made to highlight the effect of using MBEs on the response of the studied RMSW building. The results showed a significant enhancement in the seismic resilience of the building by using confined MBEs at the shear walls' extreme.
Journal of Performance of Constructed Facilities, 2020
AbstractSeveral experimental and analytical studies have evaluated the seismic response of reinfo... more AbstractSeveral experimental and analytical studies have evaluated the seismic response of reinforced masonry (RM) shear walls either as a component (i.e., planar rectangular walls) or as a system ...
Journal of Performance of Constructed Facilities, 2017
AbstractMitigation of blast effects caused by accidental explosions is one of the major challenge... more AbstractMitigation of blast effects caused by accidental explosions is one of the major challenges in structural engineering. Fiber-reinforced polymer (FRP) sandwich panels offer promising systems for blast mitigation applications due to their considerable energy absorption compared to other materials with similar density. The FRP sandwich panels can have different inner core configurations that can be filled with other materials whenever needed. This paper numerically evaluates the effectiveness of new FRP honeycomb sandwich panels in resisting blast loads. A numerical model has been created using nonlinear explicit finite element simulation. Then, the model has been validated using the experimental field tests in the literature. Twelve FRP panels with different inner core configurations have been proposed to enhance the panels’ performance by reducing their peak deformation and increasing their energy dissipation. The paper also investigates the effect of filling the FRP sandwich panels with sand on the...
Journal of Wind Engineering and Industrial Aerodynamics, 2012
Wind-induced instantaneous pressures on low building envelopes continuously vary in temporal and ... more Wind-induced instantaneous pressures on low building envelopes continuously vary in temporal and spatial dimensions and this may lead to significant torsional moments on the building's lateral load resisting system. Studies on wind-induced torsional loads on low buildings are very limited. Wind-induced torsion provisions in the American Society of Civil Engineers Standard (ASCE 7-10), the National Building Code of Canada (NBCC 2010), and the European Code (EN 1991-1-4) were reviewed and compared for three gabled-roof (18.4 o ) low buildings. Significant discrepancies were found among the provisions of these wind standards in evaluating torsional wind loads on low buildings. In addition, wind-induced torsional loads on low buildings have been measured in a boundary layer wind tunnel. Three low buildings, with the same plan dimensions but different gabled-roof angles (0 o , 18.4 o , 45 o ) and two different heights (i.e. full, and half eave building height) were tested in simulated open and urban terrain exposures for different wind directions (from 0 o to 180 o every 15 o ). The experimental results were compared with current wind-induced torsional load provisions. It was found that NBCC 2010 underestimates the torsional moments on low buildings significantly.
Over the past few decades there has been a substantial increase in the number of multi-story buil... more Over the past few decades there has been a substantial increase in the number of multi-story buildings constructed with reinforced masonry (RM). Similar to reinforced concrete (RC) buildings, shear walls are a popular lateral load resisting system in regions of high seismic activity due to its capability to provide lateral stiffness, strength and energy dissipation. One of the parameters that affects the inelastic behaviour and ductility of RM shear walls is the shear span to depth ratio, M/Vdv. This paper experimentally investigates the effect of M/Vdv on the seismic performance of RM shear walls that are dominated by diagonal shear failure. The experimental work involves two identical full-scale fully grouted rectangular RM shear walls, W-M/Vdv1.2 and W-M/Vdv1.8, tested under in-plane axial compressive stress and cyclic lateral excitations. Wall W-M/Vdv1.8 was subjected to a top moment so that M/Vdv was equal to 1.875, as compared to a value of 1.25 for wall W-M/Vdv1.2 that was tested without a top moment. Most of the existing design equations for nominal in-plane shear strength, Vn, for RM shear walls, including the current provisions of the Canadian Standards CSA S304-14, the Masonry Standards Joint Committee MSJC (2013), and the New Zealand code (2004) for masonry structures, limit the effect of the M/Vdv to an upper value of 1.0. The test results show a significant reduction of 25% in the shear strength when M/Vdv is increased, which means that limiting the effect of M/Vdv to an upper value of 1.0 is overestimating the Vn of RM shear walls at high values of M/Vdv. However, W-M/Vdv1.8 was able to achieve higher levels of displacement ductility. More results were analyzed and are presented in this paper according to force-based, displacement-based, and performance-based seismic design considerations.
Journal of Structural Engineering-asce, Dec 1, 2019
AbstractA considerable amount of research studies have demonstrated the capability of metallic sa... more AbstractA considerable amount of research studies have demonstrated the capability of metallic sandwich panels in dissipating blast loading energy. Metallic sandwich panels dissipate blast energy t...
Journal of Structural Engineering-asce, Dec 1, 2020
AbstractIn typical wall load-bearing reinforced-masonry (RM) buildings, the lateral and vertical ... more AbstractIn typical wall load-bearing reinforced-masonry (RM) buildings, the lateral and vertical forces are resisted by rectangular shear walls. Thus, the walls are subjected to high vertical force...
Journal of Structural Engineering-asce, Apr 1, 2020
AbstractReinforced masonry buildings typically have a load-bearing wall structural system. Thus, ... more AbstractReinforced masonry buildings typically have a load-bearing wall structural system. Thus, the reinforced masonry shear walls must be capable of resisting both vertical forces from gravity lo...
Shear wall system is a common seismic force resisting system that is used for both reinforced mas... more Shear wall system is a common seismic force resisting system that is used for both reinforced masonry (RM) and reinforced concrete (RC) buildings. RM shear walls can provide a considerable level of ductility like RC walls, especially for walls with boundary elements. The latest provisions of the Canadian Standard for Masonry allowed a higher level of ductility for RM shear walls based on their ductile response. This paper aims to estimate the quantities of construction materials required for RM shear walls compared to those of RC walls. Three multistorey RM shear wall buildings with different heights located in three different cities in Canada were selected. 5-, 10-, and 15-storey buildings were located in Toronto, Montreal, and Vancouver cities which represent three different levels of seismic hazard. For each building's height and location, the RM shear walls were designed with the level of ductility that results in the least construction material quantities. The analysis and design procedures were repeated for each case when RC material was used. The amount of construction materials used for the shear walls of each building was evaluated for both RM and RC cases and they were compared. Moreover, the cost of labour and temporary works for RM and RC shear walls was estimated and compared. The comparisons showed that RM shear wall construction can be as economic as the RC one for different walls' ductility levels.
Confining existing concrete and masonry columns by Carbon Fiber Reinforced Polymers (CFRP) is a b... more Confining existing concrete and masonry columns by Carbon Fiber Reinforced Polymers (CFRP) is a beneficial method for enhancing the column axial capacity and ductility. This paper presents an experimental investigation of the CFRP confinement influence on the uniaxial compression stress-strain behavior of concrete block masonry columns. Scaled fully grouted concrete block masonry columns, with a square cross section, were confined by continuous CFRP jackets and tested under concentric axial loading up to failure. The results indicate that CFRP enhances the ultimate axial strain and the axial load capacity by up to 281% and 79%, respectively compared to unreinforced columns. In this study, the effect of corner radius and the thickness of CFRP jackets are investigated. Special attention was also given to the effective tensile strain in the CFRP jackets. Finally, the CNR-DT 200 R1 confinement model, the only guide addressing strengthening masonry columns with external FRP composites, was assessed and refined equation is proposed.
Fiber optic sensors have been increasingly utilized in structural health monitoring of large-scal... more Fiber optic sensors have been increasingly utilized in structural health monitoring of large-scale civil structures. Bare fiber sensors are quite brittle, and therefore, their installation and embedment in reinforced concrete elements can be challenging, particularly when using uncommon materials as internal reinforcements in concrete. In the present study, a fiber optic strain sensor is preinstalled on a supplemental bar of adequate length and appropriate diameter. The sensor is attached to a glass fiber-reinforced polymer (GFRP) reinforcing bar in concrete flexural element. Performance under static-loading conditions has been evaluated, and the results have shown potential toward applying the technique to large-scale structures. Another objective of the present study is to develop a numerical model that represents the interaction between the concrete, the reinforcement steel, and the supplemental GFRP rebar, which has the sensor mounted on. The model is calibrated using experimental results. The model can be used to investigate varying parameters including material properties (e.g., compressive strength of concrete), geometrical data (e.g., the length of the supplemental rebar), and loading and boundary conditions, consequently eliminating the need to perform a large number of full-scale costly experiments. The developed model exhibited nearly identical behavior to the experiments after calibration. The study shows that the performance of the present sensing system is primarily affected by the relative sizes of the main and supplemental bars.
Abstract The concept of resilience is gaining increased attention in disaster management due to t... more Abstract The concept of resilience is gaining increased attention in disaster management due to the recent awareness of the need to reduce the detrimental post-event effects of natural disasters, e.g., earthquakes. Resilience is a practical concept that includes pre-event (preparedness and mitigation) and post-event (response and recovery) activities. Quantitative resilience assessment approaches are needed to compare the available mitigation strategies to decide on the most suitable strategy and provide better support for decision-making procedures. In this study, a methodology for quantifying the seismic resilience of reinforced masonry shear wall (RMSW) buildings with end-confined masonry boundary elements is implemented. The uncertainties associated with structural and non-structural losses and estimated recovery time uncertainties are considered while quantifying the resilience index of RMSW buildings. The archetype buildings studied have 8-, 10-, and 12-storey heights and are located in Vancouver, representing a high seismic zone in Canada. First, a numerical model was developed using OpenSees to derive the fragility surface for the studied archetypes subjected to bi-directional horizontal excitation. Second, a Monte Carlo simulation was performed to quantify the resilience index of each archetype considering the above-mentioned uncertainties. The results prove the robustness of ductile RMSW buildings having end-confined MBEs in mitigating the losses associated with disaster events. Additionally, the findings provide comprehensive and valuable information for earthquake mitigation measures and disaster risk reduction programmes.
The concept of seismic resilience plays an important role in seismic assessment of structures as ... more The concept of seismic resilience plays an important role in seismic assessment of structures as it assesses the capability of a system to withstand an unwanted event, such as earthquakes, by estimating the losses and determining the system's functionality and sustainability during and after such event. In this study, a framework was utilized to assess the seismic resilience of Reinforced Masonry Shear Wall (RMSW) buildings as well as studying the impact of incorporating Masonry Boundary Elements (MBEs) at the ends of RMSW. To achieve this goal, a ten-story RMSW building was numerically modelled in OpenSees to assess the seismic performance and resilience of the system when adding confined MBEs. The selected building is located in Montreal, Canada, and initially designed to be built having rectangular walls. Subsequently, the walls were redesigned to integrate MBEs at their outermost fibre to help increase the ductility and strength of the RMSWs. A full 3D wide-column macro-modelling approach was used to simulate the dynamic response of the archetype building. Validation of the modelling approach was done against available experimental tests as an initial step to ensure the robustness of the model in predicting the inelastic response of the building. Subsequently, the models were analyzed against multiple ground motion records using Incremental Dynamic Analysis to identify the initiation of collapse alongside developing the fragility curves of the building. The system-level seismic performance of the building was assessed after incorporating MBEs. The resilience of the building was assessed using the developed fragility functions, and a comparison was made to highlight the effect of using MBEs on the response of the studied RMSW building. The results showed a significant enhancement in the seismic resilience of the building by using confined MBEs at the shear walls' extreme.
Journal of Performance of Constructed Facilities, 2020
AbstractSeveral experimental and analytical studies have evaluated the seismic response of reinfo... more AbstractSeveral experimental and analytical studies have evaluated the seismic response of reinforced masonry (RM) shear walls either as a component (i.e., planar rectangular walls) or as a system ...
Journal of Performance of Constructed Facilities, 2017
AbstractMitigation of blast effects caused by accidental explosions is one of the major challenge... more AbstractMitigation of blast effects caused by accidental explosions is one of the major challenges in structural engineering. Fiber-reinforced polymer (FRP) sandwich panels offer promising systems for blast mitigation applications due to their considerable energy absorption compared to other materials with similar density. The FRP sandwich panels can have different inner core configurations that can be filled with other materials whenever needed. This paper numerically evaluates the effectiveness of new FRP honeycomb sandwich panels in resisting blast loads. A numerical model has been created using nonlinear explicit finite element simulation. Then, the model has been validated using the experimental field tests in the literature. Twelve FRP panels with different inner core configurations have been proposed to enhance the panels’ performance by reducing their peak deformation and increasing their energy dissipation. The paper also investigates the effect of filling the FRP sandwich panels with sand on the...
Journal of Wind Engineering and Industrial Aerodynamics, 2012
Wind-induced instantaneous pressures on low building envelopes continuously vary in temporal and ... more Wind-induced instantaneous pressures on low building envelopes continuously vary in temporal and spatial dimensions and this may lead to significant torsional moments on the building's lateral load resisting system. Studies on wind-induced torsional loads on low buildings are very limited. Wind-induced torsion provisions in the American Society of Civil Engineers Standard (ASCE 7-10), the National Building Code of Canada (NBCC 2010), and the European Code (EN 1991-1-4) were reviewed and compared for three gabled-roof (18.4 o ) low buildings. Significant discrepancies were found among the provisions of these wind standards in evaluating torsional wind loads on low buildings. In addition, wind-induced torsional loads on low buildings have been measured in a boundary layer wind tunnel. Three low buildings, with the same plan dimensions but different gabled-roof angles (0 o , 18.4 o , 45 o ) and two different heights (i.e. full, and half eave building height) were tested in simulated open and urban terrain exposures for different wind directions (from 0 o to 180 o every 15 o ). The experimental results were compared with current wind-induced torsional load provisions. It was found that NBCC 2010 underestimates the torsional moments on low buildings significantly.
Over the past few decades there has been a substantial increase in the number of multi-story buil... more Over the past few decades there has been a substantial increase in the number of multi-story buildings constructed with reinforced masonry (RM). Similar to reinforced concrete (RC) buildings, shear walls are a popular lateral load resisting system in regions of high seismic activity due to its capability to provide lateral stiffness, strength and energy dissipation. One of the parameters that affects the inelastic behaviour and ductility of RM shear walls is the shear span to depth ratio, M/Vdv. This paper experimentally investigates the effect of M/Vdv on the seismic performance of RM shear walls that are dominated by diagonal shear failure. The experimental work involves two identical full-scale fully grouted rectangular RM shear walls, W-M/Vdv1.2 and W-M/Vdv1.8, tested under in-plane axial compressive stress and cyclic lateral excitations. Wall W-M/Vdv1.8 was subjected to a top moment so that M/Vdv was equal to 1.875, as compared to a value of 1.25 for wall W-M/Vdv1.2 that was tested without a top moment. Most of the existing design equations for nominal in-plane shear strength, Vn, for RM shear walls, including the current provisions of the Canadian Standards CSA S304-14, the Masonry Standards Joint Committee MSJC (2013), and the New Zealand code (2004) for masonry structures, limit the effect of the M/Vdv to an upper value of 1.0. The test results show a significant reduction of 25% in the shear strength when M/Vdv is increased, which means that limiting the effect of M/Vdv to an upper value of 1.0 is overestimating the Vn of RM shear walls at high values of M/Vdv. However, W-M/Vdv1.8 was able to achieve higher levels of displacement ductility. More results were analyzed and are presented in this paper according to force-based, displacement-based, and performance-based seismic design considerations.
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Papers by Khaled Galal