Periodical vision-based inspection is a principal form of structural health monitoring (SHM) tech... more Periodical vision-based inspection is a principal form of structural health monitoring (SHM) technique. Over the last decades, vision-based artificial intelligence (AI) has successfully facilitated an effortless inspection system owing to its exceptional ability of accuracy of defects’ pattern recognition. However, most deep learning (DL)-based methods detect one specific type of defect, whereas DL has a high proficiency in multiple object detection. This study developed a dataset of two types of defects, i.e., concrete crack and spalling, and applied various pre-built convolutional neural network (CNN) models, i.e., VGG-19, ResNet-50, InceptionV3, Xception, and MobileNetV2 to classify these concrete defects. The dataset developed for this study has one of the largest collections of original images of concrete crack and spalling and avoided the augmentation process to replicate a more real-world condition, which makes the dataset one of a kind. Moreover, a detailed sensitivity analy...
Proceedings of International Structural Engineering and Construction, 2021
This comparative study probabilistically assesses the relative safety margins of code-compliant a... more This comparative study probabilistically assesses the relative safety margins of code-compliant and pre-seismic code RC buildings with different heights in a region of medium seismicity. Detailed structural design and fiber-based modeling of six benchmark structures, namely two code-compliant buildings and two pre-code structures before and after retrofit, are undertaken to develop fragility functions using several earthquake records representing the most critical seismic scenario in the study area. Several inelastic dynamic analyses are performed to assess the seismic response and derive a range of fragility functions for the six benchmark buildings. Compared with contemporary structures, the study highlights the vulnerability of pre-code buildings due to the insufficient stiffness, strength, and ductility provided by their lateral force resisting systems. A practical retrofit solution for pre-code structures is subsequently assessed using the methodology adopted for other modern a...
AbstractConcentric braced frames (CBFs) are commonly used all over the world to resist seismic fo... more AbstractConcentric braced frames (CBFs) are commonly used all over the world to resist seismic forces in buildings. Buckling, however, is a major concern for CBFs, in which they lose their strength...
High levels of investments and population densities are represented in the building inventory in ... more High levels of investments and population densities are represented in the building inventory in the UAE. The number of buildings in the existing inventory that may be at risk because of the inefficient seismic design provisions at the time they were constructed cannot be underestimated. Moreover, a crucial role in the recovery period following an earthquake is played by emergency facilities. Hence, this study focuses on the seismic fragility assessment of buildings representing substandard and emergency structures when subjected to potential earthquake scenarios in the UAE. Nine reference buildings representing the building inventory in a highly populated seismically active area in the UAE are selected based on an on-ground survey. Detailed structural design and fibre-based modelling are carried out for the reference structures, and forty earthquake records are selected to represent potential earthquake scenarios in the study area. A wide range of local and global response paramete...
Concentric Braced Frames (CBFs) are commonly used all over the world to resist seismic forces in ... more Concentric Braced Frames (CBFs) are commonly used all over the world to resist seismic forces in buildings. Buckling, however, is a major concern for CBFs where they lose their strength and stiffness when subjected to load reversals during earthquakes. To tackle this problem, a novel easy-to-fabricate lowcost Spring Based Piston Bracing (SBPB) system is developed with single and double friction spring configurations. In this system, a brace member can carry a large magnitude of tension and compression forces where a special spring is employed in the piston cylinder. Stable and self-centering hysteresis behavior is achieved when the system is subjected to qualifying quasi-static loading. Strain rate effect is assessed, and comparable results are achieved without any performance degradation. Numerical simulation shows excellent matching with the test results. Two four-story braced steel buildings are designed: a) utilizing Buckling Restrained Braces (BRBs) and b) SBPB and their perfor...
Due to the increasing demand for renewable energy resources, there is an increase in the demand f... more Due to the increasing demand for renewable energy resources, there is an increase in the demand for dam construction for the purpose of producing hydropower. India plans to produce 175GW of its power from renewable resources by 2022, including several new dams that are located in highly seismic zones. The seismic performance evaluation of concrete dams has been an extensive area of research specifically after the Koyna Dam incident in India, and various numerical evaluation approaches have been proposed to evaluate the seismic performance of dams such as discrete and smeared crack approach, and the extended and discrete finite element methods. In this study, the performance of the Koyna Dam was evaluated utilizing a scaled finite element model and performing nonlinear time history analysis. The concrete damage plasticity (CDP) model was used to represent the structural behavior as well as the tensile damage development during earthquake loading. Loma Prieta’s time history record, sc...
Earthquakes are considered as one of the most devastating phenomena that cause huge human and eco... more Earthquakes are considered as one of the most devastating phenomena that cause huge human and economic losses. Concentric Braced Frames (CBFs) have been developed and used in many places all over the world to resist these forces. Buckling, however, is a major concern for CBFs where they lose their strength and stiffness when subjected to severe earthquakes. To solve this issue, many bracing systems have been developed by researchers in the past few decades. These systems exhibit fat hysteresis loops which contribute to the higher amount of damping and thus can reduce velocity and acceleration of the system but they do not have the self-centering property. To solve this issue, a novel Spring Based Piston Bracing (SBPB) system is developed. In this system, a brace member can carry a large magnitude of tension and compression forces where a special spring is employed in the piston cylinder. Stable and self-centering hysteresis behavior is achieved when the system is subjected to qualif...
A systematic seismic vulnerability assessment of a benchmark 8-story structure representing pre-s... more A systematic seismic vulnerability assessment of a benchmark 8-story structure representing pre-seismic code frame buildings in a highly populated and seismically active area is conducted in this study. Detailed structural design and fiber-based modeling are carried out for the reference structure. Forty earthquake records are selected to represent potential earthquake scenarios in the study area. Al large number of inelastic pushover analyses (IPAs) and incremental dynamic analyses (IDAs) are performed to select the performance criteria and to derive fragility relationships for the reference building. It is concluded that this category of pre-code structures is substantially vulnerable to seismic loads. The derived fragility curves for the retrofitted reference structure using Buckling Restrained Braces (BRBs) proved that such technique is efficient in reducing the seismic losses of pre-code frame structures and increasing public safety.
Proceedings of International Structural Engineering and Construction
The number of existing buildings that may be at risk because of insufficient seismic design provi... more The number of existing buildings that may be at risk because of insufficient seismic design provisions cannot be underestimated. Recent studies have confirmed the pressing need for the seismic retrofit of pre-code structures to reduce their probability of collapse. A number of retrofit approaches are therefore assessed in this study, namely reinforced concrete jacketing, fiber reinforced polymers wrapping, and installing externally unbonded steel plates. Detailed structural design and fiber-based modeling are carried out for five reference structures representing frame and shear wall multi-story buildings before and after retrofit. Forty earthquake records are selected to represent potential earthquake scenarios in a region of medium seismicity that was selected as a reference study area. A large number of inelastic pushover and dynamic analyses are performed to assess the lateral capacity and to derive a wide range of fragility relationships for the reference structures. The highes...
Periodical vision-based inspection is a principal form of structural health monitoring (SHM) tech... more Periodical vision-based inspection is a principal form of structural health monitoring (SHM) technique. Over the last decades, vision-based artificial intelligence (AI) has successfully facilitated an effortless inspection system owing to its exceptional ability of accuracy of defects’ pattern recognition. However, most deep learning (DL)-based methods detect one specific type of defect, whereas DL has a high proficiency in multiple object detection. This study developed a dataset of two types of defects, i.e., concrete crack and spalling, and applied various pre-built convolutional neural network (CNN) models, i.e., VGG-19, ResNet-50, InceptionV3, Xception, and MobileNetV2 to classify these concrete defects. The dataset developed for this study has one of the largest collections of original images of concrete crack and spalling and avoided the augmentation process to replicate a more real-world condition, which makes the dataset one of a kind. Moreover, a detailed sensitivity analy...
Proceedings of International Structural Engineering and Construction, 2021
This comparative study probabilistically assesses the relative safety margins of code-compliant a... more This comparative study probabilistically assesses the relative safety margins of code-compliant and pre-seismic code RC buildings with different heights in a region of medium seismicity. Detailed structural design and fiber-based modeling of six benchmark structures, namely two code-compliant buildings and two pre-code structures before and after retrofit, are undertaken to develop fragility functions using several earthquake records representing the most critical seismic scenario in the study area. Several inelastic dynamic analyses are performed to assess the seismic response and derive a range of fragility functions for the six benchmark buildings. Compared with contemporary structures, the study highlights the vulnerability of pre-code buildings due to the insufficient stiffness, strength, and ductility provided by their lateral force resisting systems. A practical retrofit solution for pre-code structures is subsequently assessed using the methodology adopted for other modern a...
AbstractConcentric braced frames (CBFs) are commonly used all over the world to resist seismic fo... more AbstractConcentric braced frames (CBFs) are commonly used all over the world to resist seismic forces in buildings. Buckling, however, is a major concern for CBFs, in which they lose their strength...
High levels of investments and population densities are represented in the building inventory in ... more High levels of investments and population densities are represented in the building inventory in the UAE. The number of buildings in the existing inventory that may be at risk because of the inefficient seismic design provisions at the time they were constructed cannot be underestimated. Moreover, a crucial role in the recovery period following an earthquake is played by emergency facilities. Hence, this study focuses on the seismic fragility assessment of buildings representing substandard and emergency structures when subjected to potential earthquake scenarios in the UAE. Nine reference buildings representing the building inventory in a highly populated seismically active area in the UAE are selected based on an on-ground survey. Detailed structural design and fibre-based modelling are carried out for the reference structures, and forty earthquake records are selected to represent potential earthquake scenarios in the study area. A wide range of local and global response paramete...
Concentric Braced Frames (CBFs) are commonly used all over the world to resist seismic forces in ... more Concentric Braced Frames (CBFs) are commonly used all over the world to resist seismic forces in buildings. Buckling, however, is a major concern for CBFs where they lose their strength and stiffness when subjected to load reversals during earthquakes. To tackle this problem, a novel easy-to-fabricate lowcost Spring Based Piston Bracing (SBPB) system is developed with single and double friction spring configurations. In this system, a brace member can carry a large magnitude of tension and compression forces where a special spring is employed in the piston cylinder. Stable and self-centering hysteresis behavior is achieved when the system is subjected to qualifying quasi-static loading. Strain rate effect is assessed, and comparable results are achieved without any performance degradation. Numerical simulation shows excellent matching with the test results. Two four-story braced steel buildings are designed: a) utilizing Buckling Restrained Braces (BRBs) and b) SBPB and their perfor...
Due to the increasing demand for renewable energy resources, there is an increase in the demand f... more Due to the increasing demand for renewable energy resources, there is an increase in the demand for dam construction for the purpose of producing hydropower. India plans to produce 175GW of its power from renewable resources by 2022, including several new dams that are located in highly seismic zones. The seismic performance evaluation of concrete dams has been an extensive area of research specifically after the Koyna Dam incident in India, and various numerical evaluation approaches have been proposed to evaluate the seismic performance of dams such as discrete and smeared crack approach, and the extended and discrete finite element methods. In this study, the performance of the Koyna Dam was evaluated utilizing a scaled finite element model and performing nonlinear time history analysis. The concrete damage plasticity (CDP) model was used to represent the structural behavior as well as the tensile damage development during earthquake loading. Loma Prieta’s time history record, sc...
Earthquakes are considered as one of the most devastating phenomena that cause huge human and eco... more Earthquakes are considered as one of the most devastating phenomena that cause huge human and economic losses. Concentric Braced Frames (CBFs) have been developed and used in many places all over the world to resist these forces. Buckling, however, is a major concern for CBFs where they lose their strength and stiffness when subjected to severe earthquakes. To solve this issue, many bracing systems have been developed by researchers in the past few decades. These systems exhibit fat hysteresis loops which contribute to the higher amount of damping and thus can reduce velocity and acceleration of the system but they do not have the self-centering property. To solve this issue, a novel Spring Based Piston Bracing (SBPB) system is developed. In this system, a brace member can carry a large magnitude of tension and compression forces where a special spring is employed in the piston cylinder. Stable and self-centering hysteresis behavior is achieved when the system is subjected to qualif...
A systematic seismic vulnerability assessment of a benchmark 8-story structure representing pre-s... more A systematic seismic vulnerability assessment of a benchmark 8-story structure representing pre-seismic code frame buildings in a highly populated and seismically active area is conducted in this study. Detailed structural design and fiber-based modeling are carried out for the reference structure. Forty earthquake records are selected to represent potential earthquake scenarios in the study area. Al large number of inelastic pushover analyses (IPAs) and incremental dynamic analyses (IDAs) are performed to select the performance criteria and to derive fragility relationships for the reference building. It is concluded that this category of pre-code structures is substantially vulnerable to seismic loads. The derived fragility curves for the retrofitted reference structure using Buckling Restrained Braces (BRBs) proved that such technique is efficient in reducing the seismic losses of pre-code frame structures and increasing public safety.
Proceedings of International Structural Engineering and Construction
The number of existing buildings that may be at risk because of insufficient seismic design provi... more The number of existing buildings that may be at risk because of insufficient seismic design provisions cannot be underestimated. Recent studies have confirmed the pressing need for the seismic retrofit of pre-code structures to reduce their probability of collapse. A number of retrofit approaches are therefore assessed in this study, namely reinforced concrete jacketing, fiber reinforced polymers wrapping, and installing externally unbonded steel plates. Detailed structural design and fiber-based modeling are carried out for five reference structures representing frame and shear wall multi-story buildings before and after retrofit. Forty earthquake records are selected to represent potential earthquake scenarios in a region of medium seismicity that was selected as a reference study area. A large number of inelastic pushover and dynamic analyses are performed to assess the lateral capacity and to derive a wide range of fragility relationships for the reference structures. The highes...
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