This report presents structural-engineering information on three medical facilities: two
located ... more This report presents structural-engineering information on three medical facilities: two located on the West Coast of the United States and one located on the East Coast. The three facilities have the same plan and vertical geometry: a geometry that is based on an existing facility in San Fernando Valley, in Southern California. The structural-engineering information was prepared using as-built data from the existing facility in the San Fernando Valley. This facility was constructed in the early 1970s to meet the seismic requirements of the 1970 Uniform Building Code (ICBO, 1970). For the intended purpose of the demonstration hospitals, the framing system of the existing facility was modified slightly to a rectangular plan profile and the penthouse atop the existing facility was eliminated. The vertical shafts in the building for mechanical and vertical transportation systems were replaced by typical floor framing. The resulting building is termed West Coast 1970s (or WC70) in this report. The Uniform Building Code was used for seismic design in California from the late 1920s through to the time of the introduction of the 2000 International Building Code in 2001. In the late 1960s, the Uniform Building Code was substantially revised. Limits on allowable displacements in buildings were introduced in the 1976 edition of the Uniform Building Code (ICBO, 1976). This change led to substantial increases in the required elastic lateral stiffness, and subsequently the lateral strength, of moment-frame buildings such as the existing facility. As such, the stiffness and strength of mid-to-late 1970s moment-frame construction are significantly greater than those of 1960s construction.
ABSTRACT In recent years, the concepts of resilience and sustainability have become very topical ... more ABSTRACT In recent years, the concepts of resilience and sustainability have become very topical and popular. The concept of sustainability rose to prominence in the late 1980s and became a central issue in world politics, when the construction industry began to generate the first sustainable building assessment systems with more or less equally weighted environmental, economic, and social aspects for office buildings over their life cycles. On the other hand, resilience is usually connected to the occurrence of extreme events during the life cycle of structures and infrastructures. In the last decade, it has been used to minimize specifically direct and indirect losses from hazards through enhanced resistance and robustness to extreme events, as well as more effective recovery strategies. A detailed comparison of the studies dealing with either infrastructure sustainability or resilience presented in this paper leads to the conclusion that they have a vast number of similarities and common characteristics. For instance, they both combine structural analyses with social and economic aspects; they both rely on techniques for the life-cycle analysis and decision making; they both are in an early stage, where the academic world is trying to find the best way to promote the application of the scientific results among professional engineers and the industry. Indeed, both approaches try to optimize a system, such as a civil infrastructure system, with respect to structural design, utilized material, maintenance plans, management strategies, and impacts on the society. However, for the most part, researchers and practitioners focusing on either resilience or sustainability operate without a mutual consideration of the findings, which leads to a severe inefficiency. Therefore, this paper suggests that resilience and sustainability are complementary and should be used in an integrated perspective. In particular, the proposed approach is rooted in the well-established framework of risk assessment. The impact of the infrastructure and its service states on the society in normal operational conditions (assessed by sustainability analysis) and after exceptional events (assessed by resilience analysis) should be weighted by the associated probabilities of occurrence and combined in a global impact assessment. The proposed perspective and assessment technique is applicable to various types of civil infrastructure systems, but the case of transportation networks and bridge systems is emphasized herein. A numerical application dealing with the comparative analysis of two possible bridge layouts is presented to exemplify the approach. The results show that both resilience and sustainability analyses assess a relevant amount of the impact of the bridge on the community where it is built, so neither one can be neglected. (C) 2014 American Society of Civil Engineers.
Dynamic analysis of structures subjected to earthquake excitation is a time-consuming process, pa... more Dynamic analysis of structures subjected to earthquake excitation is a time-consuming process, particularly in the case of extremely small time step required, or in the presence of high geometric and material nonlinearity. Performing parametric studies in such cases is even more tedious. The advancement of computer graphics hardware in recent years enables efficient training of artificial neural networks that are well-known to be capable of learning highly nonlinear mappings. Traditional artificial neural networks are usually built on fixed architecture which consists of a fixed number of nodes and hidden layers, and consequently is more likely to get stuck in local minima during training. In this study, artificial neural networks are developed with adaptive training algorithms, which enables automatic nodes generation and layers addition. The hyperbolic tangent function is selected as the activation function. Stochastic Gradient Descent and Back Propagation algorithms are adopted to train the networks. The neural networks initiate with a small number of hidden layers and nodes. During training, the performance of the network is continuously tracked, and new nodes or layers are added to the hidden layers if the neural network reaches its capacity. At the end of the training process, the network with appropriate architecture is automatically formed. The performance of the networks has been validated for inelastic shear frames, as well as rocking structures, of which both are first built in finite element program for dynamic analysis to generate training data. Energy dissipation is considered during rocking motion using a Hilber-Hughes-Taylor numerically dissipative time step integration scheme. Results have shown the developed networks can successfully predict the time-history response of the shear frame systems subjected to real ground motion records. The response of rocking structures can be mostly well predicted although there exist small discrepancies at some instants. Furthermore, the efficiency of the proposed neural networks is also examined, which shows the computational time can be reduced by 43% than FE models, when the Graphical Processing Units acceleration is enabled. This indicates the trained networks can be utilized to generate rocking spectrums of structures more efficiently which demands a large number of time-history analyses.
The special issue entitled ‘‘Resilience and Sustainability of Civil Infrastructures under Extreme... more The special issue entitled ‘‘Resilience and Sustainability of Civil Infrastructures under Extreme Loads’’ updates the state of the art and perspectives focused on cutting-edge approaches to enhance structures’ resilience and sustainability under extreme loading events, including theoretical investigation, numerical simulation, and experimental study, keeping an eye on the seismic performance of civil structures. Notably, some innovative energy dissipative devices and resilient structural forms, which are encompassed in this special issue, would provide valuable references for the engineering application of resilient and sustainable civil infrastructures in the near future.
Earthquake-induced building collapses have been effectively mitigated in recent years. However, e... more Earthquake-induced building collapses have been effectively mitigated in recent years. However, earthquake-induced economic losses have continued to rise. Following the objective and procedure of next-generation performance-based seismic design, the economic loss prediction method proposed by FEMA P-58 (referred to as “the FEMA P-58 method” hereafter) is introduced for regional earthquake loss prediction in this study. The engineering demand parameters (EDPs) for a large number of buildings within a region are efficiently obtained through nonlinear time history analysis (THA) using multi-story concentrated-mass shear (MCS) models. The building data, including structural and nonstructural components, is obtained through field investigation, structural and architectural drawings, and default database published from the FEMA P-58 document. The proposed FEMA P-58 method is implemented for a region located in China to demonstrate the implementation and advantage of using the FEMA P-58 me...
Journal of Structural Integrity and Maintenance, 2022
In this paper, a novel deterioration and damage identification procedure (DIP) is presented and a... more In this paper, a novel deterioration and damage identification procedure (DIP) is presented and applied to building models. The challenge associated with applications on these types of structures is related to the strong correlation of responses, which gets further complicated when coping with real ambient vibrations with high levels of noise. Thus, a DIP is designed utilizing low-cost ambient vibrations to analyze the acceleration responses using the Stockwell transform (ST) to generate spectrograms. Subsequently, the ST outputs become the input of two series of Convolutional Neural Networks (CNNs) established for identifying deterioration and damage to the building models. To the best of our knowledge, this is the first time that both damage and deterioration are evaluated on building models through a combination of ST and CNN with high accuracy.
Concentrically braced frame (CBF) is an effective and prevalent seismic force resisting system wh... more Concentrically braced frame (CBF) is an effective and prevalent seismic force resisting system which is commonly used in low-rise buildings. This type of structural system utilizes steel braces to provide the stiffness and strength needed to dissipate earthquake energy. Several bracing configurations have been proposed in different building codes worldwide. These codes provide detailed design requirements for the structural members and connections, but no guidance is provided in selecting the best bracing configuration for the design. In this study, the impact of the bracing configuration on the seismic response of a five-story prototype office building located in Vancouver, Canada, is systematically examined. Five different bracing configurations were designed according to the National Building Code of Canada and CSA S16 standard. Detailed structural responses, initial costs, and life cycle costs of the prototype building with five different bracing configurations were systematically compared. The results show that the different bracing configurations play an important role in sizing the structural members, which impacts the initial material usage and the overall life cycle cost of the building.
Computer-Aided Civil and Infrastructure Engineering, 2020
Reinforced concrete buildings are commonly used around the world. With recent earthquakes worldwi... more Reinforced concrete buildings are commonly used around the world. With recent earthquakes worldwide, rapid structural damage inspection and repair cost evaluation are crucial for building owners and policy makers to make informed risk management decisions. To improve the efficiency of such inspection, advanced computer vision techniques based on convolution neural networks have been adopted in recent research to rapidly quantify the damage state of structures. In this paper, an advanced object detection neural network, named YOLO-v2, is implemented which achieves 98.2% and 84.5% average precision in training and testing, respectively. The proposed YOLO-v2 is used in combination with the classification neural network, which improves the identification accuracy for critical damage state of reinforced concrete structures by 7.5%. The improved classification procedures allow engineers to rapidly and more accurately quantify the damage states of the structure, and also localize the critical damage features. The identified damage state can then be integrated with the state-of-the-art performance evaluation framework to quantify the financial losses of critical reinforced concrete buildings. The results can be used by the building owners and decision makers to make informed risk management decisions immediately after the strong earthquake shaking. Hence, resources can be allocated rapidly to improve the resiliency of the community.
Traditional base isolation systems focus on isolating the seismic response of a structure in the ... more Traditional base isolation systems focus on isolating the seismic response of a structure in the horizontal direction. However, in regions where the vertical earthquake excitation is significant (such as near-fault region), a traditional base-isolated building exhibits a significant vertical vibration. To eliminate this shortcoming, a rocking-isolated system named Telescopic Column (TC) is proposed in this paper. Detailed rocking and isolation mechanism of the TC system is presented. The seismic performance of the TC is compared with the traditional elastomeric bearing (EB) and friction pendulum (FP) baseisolated systems. A 4-storey reinforced concrete moment-resisting frame (RC-MRF) is selected as the reference superstructure. The seismic response of the reference superstructure in terms of column axial forces, base shears, floor accelerations, interstory drift ratios (IDR) and collapse margin ratios (CMRs) are evaluated using OpenSees. The results of the nonlinear dynamic analysis subjected to multidirectional earthquake excitations show that the superstructure equipped with the newly proposed TC exhibits a superior response with higher margin of safety against collapse when compared with the same superstructure with the traditional base-isolation (BI) system.
Computer-Aided Civil and Infrastructure Engineering, 2021
Structural bolts are critical components used in different structural elements, such as beam-colu... more Structural bolts are critical components used in different structural elements, such as beam-column connections and friction damping devices. The clamping force in structural bolts is highly influenced by the bolt rotation. Much of the existing visionbased research about bolt rotation estimation relies on traditional computer vision algorithms such as Hough Transform to assess static images of bolts. This requires careful image preprocessing, and it may not perform well in the situation of complicated bolt assemblies, or in the presence of surrounding objects and background noise, thus hindering their real-world applications. In this study, an integrated real-time detect-track method, namely RTDT-Bolt, is proposed to monitor the bolt rotation angle. First, a real-time convolutionalneural-networks-based object detector, named YOLOv3-tiny, is established and trained to localize structural bolts. Then, the targetfree object tracking algorithm based on optical flow is implemented, to continuously monitor and quantify the rotation of structural bolts. In order to enhance the tracking performance against background noise and potential illumination changes during tracking, the YOLOv3-tiny is integrated with the optical flow tracking algorithm to re-detect the bolts when the tracking gets lost. Extensive parameter studies were conducted to identify optimal tracking performance and examine the potential limitations. The results indicate the RTDT-Bolt method can greatly enhance the tracking performance of bolt rotation, which can achieve over 90% accuracy using the recommended range for the parameters.
Buckling restrained knee brace truss moment frame (BRKBTMF) is a novel and innovative structural ... more Buckling restrained knee brace truss moment frame (BRKBTMF) is a novel and innovative structural system that utilizes the advantages of open web steel trusses and dedicated structural fuses for seismic applications. Open web steel truss are very economical and effective to span large distance. However, the conventional open web steel trusses (OWST) are not suitable for seismic application due to the lack of ductility and poor energy dissipation capacity. The introduction of buckling restrained knee braces as the dedicated structural fuses can overcome these disadvantages and allow the truss girders to be used efficiently in seismic application. In this paper, a detailed parameter study was conducted to study the performance of the BRKBTMF system with different spans. A prototype building located in Berkley, California, USA, was designed using two truss spans. Nonlinear dynamic analyses were conducted to exam the performance of the structure under the expected maximum credible earthq...
This report presents structural-engineering information on three medical facilities: two
located ... more This report presents structural-engineering information on three medical facilities: two located on the West Coast of the United States and one located on the East Coast. The three facilities have the same plan and vertical geometry: a geometry that is based on an existing facility in San Fernando Valley, in Southern California. The structural-engineering information was prepared using as-built data from the existing facility in the San Fernando Valley. This facility was constructed in the early 1970s to meet the seismic requirements of the 1970 Uniform Building Code (ICBO, 1970). For the intended purpose of the demonstration hospitals, the framing system of the existing facility was modified slightly to a rectangular plan profile and the penthouse atop the existing facility was eliminated. The vertical shafts in the building for mechanical and vertical transportation systems were replaced by typical floor framing. The resulting building is termed West Coast 1970s (or WC70) in this report. The Uniform Building Code was used for seismic design in California from the late 1920s through to the time of the introduction of the 2000 International Building Code in 2001. In the late 1960s, the Uniform Building Code was substantially revised. Limits on allowable displacements in buildings were introduced in the 1976 edition of the Uniform Building Code (ICBO, 1976). This change led to substantial increases in the required elastic lateral stiffness, and subsequently the lateral strength, of moment-frame buildings such as the existing facility. As such, the stiffness and strength of mid-to-late 1970s moment-frame construction are significantly greater than those of 1960s construction.
ABSTRACT In recent years, the concepts of resilience and sustainability have become very topical ... more ABSTRACT In recent years, the concepts of resilience and sustainability have become very topical and popular. The concept of sustainability rose to prominence in the late 1980s and became a central issue in world politics, when the construction industry began to generate the first sustainable building assessment systems with more or less equally weighted environmental, economic, and social aspects for office buildings over their life cycles. On the other hand, resilience is usually connected to the occurrence of extreme events during the life cycle of structures and infrastructures. In the last decade, it has been used to minimize specifically direct and indirect losses from hazards through enhanced resistance and robustness to extreme events, as well as more effective recovery strategies. A detailed comparison of the studies dealing with either infrastructure sustainability or resilience presented in this paper leads to the conclusion that they have a vast number of similarities and common characteristics. For instance, they both combine structural analyses with social and economic aspects; they both rely on techniques for the life-cycle analysis and decision making; they both are in an early stage, where the academic world is trying to find the best way to promote the application of the scientific results among professional engineers and the industry. Indeed, both approaches try to optimize a system, such as a civil infrastructure system, with respect to structural design, utilized material, maintenance plans, management strategies, and impacts on the society. However, for the most part, researchers and practitioners focusing on either resilience or sustainability operate without a mutual consideration of the findings, which leads to a severe inefficiency. Therefore, this paper suggests that resilience and sustainability are complementary and should be used in an integrated perspective. In particular, the proposed approach is rooted in the well-established framework of risk assessment. The impact of the infrastructure and its service states on the society in normal operational conditions (assessed by sustainability analysis) and after exceptional events (assessed by resilience analysis) should be weighted by the associated probabilities of occurrence and combined in a global impact assessment. The proposed perspective and assessment technique is applicable to various types of civil infrastructure systems, but the case of transportation networks and bridge systems is emphasized herein. A numerical application dealing with the comparative analysis of two possible bridge layouts is presented to exemplify the approach. The results show that both resilience and sustainability analyses assess a relevant amount of the impact of the bridge on the community where it is built, so neither one can be neglected. (C) 2014 American Society of Civil Engineers.
Dynamic analysis of structures subjected to earthquake excitation is a time-consuming process, pa... more Dynamic analysis of structures subjected to earthquake excitation is a time-consuming process, particularly in the case of extremely small time step required, or in the presence of high geometric and material nonlinearity. Performing parametric studies in such cases is even more tedious. The advancement of computer graphics hardware in recent years enables efficient training of artificial neural networks that are well-known to be capable of learning highly nonlinear mappings. Traditional artificial neural networks are usually built on fixed architecture which consists of a fixed number of nodes and hidden layers, and consequently is more likely to get stuck in local minima during training. In this study, artificial neural networks are developed with adaptive training algorithms, which enables automatic nodes generation and layers addition. The hyperbolic tangent function is selected as the activation function. Stochastic Gradient Descent and Back Propagation algorithms are adopted to train the networks. The neural networks initiate with a small number of hidden layers and nodes. During training, the performance of the network is continuously tracked, and new nodes or layers are added to the hidden layers if the neural network reaches its capacity. At the end of the training process, the network with appropriate architecture is automatically formed. The performance of the networks has been validated for inelastic shear frames, as well as rocking structures, of which both are first built in finite element program for dynamic analysis to generate training data. Energy dissipation is considered during rocking motion using a Hilber-Hughes-Taylor numerically dissipative time step integration scheme. Results have shown the developed networks can successfully predict the time-history response of the shear frame systems subjected to real ground motion records. The response of rocking structures can be mostly well predicted although there exist small discrepancies at some instants. Furthermore, the efficiency of the proposed neural networks is also examined, which shows the computational time can be reduced by 43% than FE models, when the Graphical Processing Units acceleration is enabled. This indicates the trained networks can be utilized to generate rocking spectrums of structures more efficiently which demands a large number of time-history analyses.
The special issue entitled ‘‘Resilience and Sustainability of Civil Infrastructures under Extreme... more The special issue entitled ‘‘Resilience and Sustainability of Civil Infrastructures under Extreme Loads’’ updates the state of the art and perspectives focused on cutting-edge approaches to enhance structures’ resilience and sustainability under extreme loading events, including theoretical investigation, numerical simulation, and experimental study, keeping an eye on the seismic performance of civil structures. Notably, some innovative energy dissipative devices and resilient structural forms, which are encompassed in this special issue, would provide valuable references for the engineering application of resilient and sustainable civil infrastructures in the near future.
Earthquake-induced building collapses have been effectively mitigated in recent years. However, e... more Earthquake-induced building collapses have been effectively mitigated in recent years. However, earthquake-induced economic losses have continued to rise. Following the objective and procedure of next-generation performance-based seismic design, the economic loss prediction method proposed by FEMA P-58 (referred to as “the FEMA P-58 method” hereafter) is introduced for regional earthquake loss prediction in this study. The engineering demand parameters (EDPs) for a large number of buildings within a region are efficiently obtained through nonlinear time history analysis (THA) using multi-story concentrated-mass shear (MCS) models. The building data, including structural and nonstructural components, is obtained through field investigation, structural and architectural drawings, and default database published from the FEMA P-58 document. The proposed FEMA P-58 method is implemented for a region located in China to demonstrate the implementation and advantage of using the FEMA P-58 me...
Journal of Structural Integrity and Maintenance, 2022
In this paper, a novel deterioration and damage identification procedure (DIP) is presented and a... more In this paper, a novel deterioration and damage identification procedure (DIP) is presented and applied to building models. The challenge associated with applications on these types of structures is related to the strong correlation of responses, which gets further complicated when coping with real ambient vibrations with high levels of noise. Thus, a DIP is designed utilizing low-cost ambient vibrations to analyze the acceleration responses using the Stockwell transform (ST) to generate spectrograms. Subsequently, the ST outputs become the input of two series of Convolutional Neural Networks (CNNs) established for identifying deterioration and damage to the building models. To the best of our knowledge, this is the first time that both damage and deterioration are evaluated on building models through a combination of ST and CNN with high accuracy.
Concentrically braced frame (CBF) is an effective and prevalent seismic force resisting system wh... more Concentrically braced frame (CBF) is an effective and prevalent seismic force resisting system which is commonly used in low-rise buildings. This type of structural system utilizes steel braces to provide the stiffness and strength needed to dissipate earthquake energy. Several bracing configurations have been proposed in different building codes worldwide. These codes provide detailed design requirements for the structural members and connections, but no guidance is provided in selecting the best bracing configuration for the design. In this study, the impact of the bracing configuration on the seismic response of a five-story prototype office building located in Vancouver, Canada, is systematically examined. Five different bracing configurations were designed according to the National Building Code of Canada and CSA S16 standard. Detailed structural responses, initial costs, and life cycle costs of the prototype building with five different bracing configurations were systematically compared. The results show that the different bracing configurations play an important role in sizing the structural members, which impacts the initial material usage and the overall life cycle cost of the building.
Computer-Aided Civil and Infrastructure Engineering, 2020
Reinforced concrete buildings are commonly used around the world. With recent earthquakes worldwi... more Reinforced concrete buildings are commonly used around the world. With recent earthquakes worldwide, rapid structural damage inspection and repair cost evaluation are crucial for building owners and policy makers to make informed risk management decisions. To improve the efficiency of such inspection, advanced computer vision techniques based on convolution neural networks have been adopted in recent research to rapidly quantify the damage state of structures. In this paper, an advanced object detection neural network, named YOLO-v2, is implemented which achieves 98.2% and 84.5% average precision in training and testing, respectively. The proposed YOLO-v2 is used in combination with the classification neural network, which improves the identification accuracy for critical damage state of reinforced concrete structures by 7.5%. The improved classification procedures allow engineers to rapidly and more accurately quantify the damage states of the structure, and also localize the critical damage features. The identified damage state can then be integrated with the state-of-the-art performance evaluation framework to quantify the financial losses of critical reinforced concrete buildings. The results can be used by the building owners and decision makers to make informed risk management decisions immediately after the strong earthquake shaking. Hence, resources can be allocated rapidly to improve the resiliency of the community.
Traditional base isolation systems focus on isolating the seismic response of a structure in the ... more Traditional base isolation systems focus on isolating the seismic response of a structure in the horizontal direction. However, in regions where the vertical earthquake excitation is significant (such as near-fault region), a traditional base-isolated building exhibits a significant vertical vibration. To eliminate this shortcoming, a rocking-isolated system named Telescopic Column (TC) is proposed in this paper. Detailed rocking and isolation mechanism of the TC system is presented. The seismic performance of the TC is compared with the traditional elastomeric bearing (EB) and friction pendulum (FP) baseisolated systems. A 4-storey reinforced concrete moment-resisting frame (RC-MRF) is selected as the reference superstructure. The seismic response of the reference superstructure in terms of column axial forces, base shears, floor accelerations, interstory drift ratios (IDR) and collapse margin ratios (CMRs) are evaluated using OpenSees. The results of the nonlinear dynamic analysis subjected to multidirectional earthquake excitations show that the superstructure equipped with the newly proposed TC exhibits a superior response with higher margin of safety against collapse when compared with the same superstructure with the traditional base-isolation (BI) system.
Computer-Aided Civil and Infrastructure Engineering, 2021
Structural bolts are critical components used in different structural elements, such as beam-colu... more Structural bolts are critical components used in different structural elements, such as beam-column connections and friction damping devices. The clamping force in structural bolts is highly influenced by the bolt rotation. Much of the existing visionbased research about bolt rotation estimation relies on traditional computer vision algorithms such as Hough Transform to assess static images of bolts. This requires careful image preprocessing, and it may not perform well in the situation of complicated bolt assemblies, or in the presence of surrounding objects and background noise, thus hindering their real-world applications. In this study, an integrated real-time detect-track method, namely RTDT-Bolt, is proposed to monitor the bolt rotation angle. First, a real-time convolutionalneural-networks-based object detector, named YOLOv3-tiny, is established and trained to localize structural bolts. Then, the targetfree object tracking algorithm based on optical flow is implemented, to continuously monitor and quantify the rotation of structural bolts. In order to enhance the tracking performance against background noise and potential illumination changes during tracking, the YOLOv3-tiny is integrated with the optical flow tracking algorithm to re-detect the bolts when the tracking gets lost. Extensive parameter studies were conducted to identify optimal tracking performance and examine the potential limitations. The results indicate the RTDT-Bolt method can greatly enhance the tracking performance of bolt rotation, which can achieve over 90% accuracy using the recommended range for the parameters.
Buckling restrained knee brace truss moment frame (BRKBTMF) is a novel and innovative structural ... more Buckling restrained knee brace truss moment frame (BRKBTMF) is a novel and innovative structural system that utilizes the advantages of open web steel trusses and dedicated structural fuses for seismic applications. Open web steel truss are very economical and effective to span large distance. However, the conventional open web steel trusses (OWST) are not suitable for seismic application due to the lack of ductility and poor energy dissipation capacity. The introduction of buckling restrained knee braces as the dedicated structural fuses can overcome these disadvantages and allow the truss girders to be used efficiently in seismic application. In this paper, a detailed parameter study was conducted to study the performance of the BRKBTMF system with different spans. A prototype building located in Berkley, California, USA, was designed using two truss spans. Nonlinear dynamic analyses were conducted to exam the performance of the structure under the expected maximum credible earthq...
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located on the West Coast of the United States and one located on the East Coast. The
three facilities have the same plan and vertical geometry: a geometry that is based on an
existing facility in San Fernando Valley, in Southern California.
The structural-engineering information was prepared using as-built data from the existing
facility in the San Fernando Valley. This facility was constructed in the early 1970s to
meet the seismic requirements of the 1970 Uniform Building Code (ICBO, 1970). For the
intended purpose of the demonstration hospitals, the framing system of the existing
facility was modified slightly to a rectangular plan profile and the penthouse atop the
existing facility was eliminated. The vertical shafts in the building for mechanical and
vertical transportation systems were replaced by typical floor framing. The resulting
building is termed West Coast 1970s (or WC70) in this report.
The Uniform Building Code was used for seismic design in California from the late
1920s through to the time of the introduction of the 2000 International Building Code in
2001. In the late 1960s, the Uniform Building Code was substantially revised. Limits on
allowable displacements in buildings were introduced in the 1976 edition of the Uniform
Building Code (ICBO, 1976). This change led to substantial increases in the required
elastic lateral stiffness, and subsequently the lateral strength, of moment-frame buildings
such as the existing facility. As such, the stiffness and strength of mid-to-late 1970s
moment-frame construction are significantly greater than those of 1960s construction.
Papers by Tony Yang
located on the West Coast of the United States and one located on the East Coast. The
three facilities have the same plan and vertical geometry: a geometry that is based on an
existing facility in San Fernando Valley, in Southern California.
The structural-engineering information was prepared using as-built data from the existing
facility in the San Fernando Valley. This facility was constructed in the early 1970s to
meet the seismic requirements of the 1970 Uniform Building Code (ICBO, 1970). For the
intended purpose of the demonstration hospitals, the framing system of the existing
facility was modified slightly to a rectangular plan profile and the penthouse atop the
existing facility was eliminated. The vertical shafts in the building for mechanical and
vertical transportation systems were replaced by typical floor framing. The resulting
building is termed West Coast 1970s (or WC70) in this report.
The Uniform Building Code was used for seismic design in California from the late
1920s through to the time of the introduction of the 2000 International Building Code in
2001. In the late 1960s, the Uniform Building Code was substantially revised. Limits on
allowable displacements in buildings were introduced in the 1976 edition of the Uniform
Building Code (ICBO, 1976). This change led to substantial increases in the required
elastic lateral stiffness, and subsequently the lateral strength, of moment-frame buildings
such as the existing facility. As such, the stiffness and strength of mid-to-late 1970s
moment-frame construction are significantly greater than those of 1960s construction.