Risk assessment and mitigation programs have been carried out over the last decades in the attempt to reduce transportation infrastructure downtime and post-disaster recovery costs.Recently,the concept of resilience g...Risk assessment and mitigation programs have been carried out over the last decades in the attempt to reduce transportation infrastructure downtime and post-disaster recovery costs.Recently,the concept of resilience gained increasing importance in design,assessment,maintenance,and rehabilitation structures and infrastructure systems,particularly bridges and transportation networks,exposed to natural and man-made hazards.In the field of disaster mitigation,frameworks have been proposed to provide a basis for development of qualitative and quantitative models quantifying the functionality and resilience at various scales,including components,groups and systems within infrastructure networks and communities.In these frameworks,the effects of aging and environmental aggressiveness must be explicitly considered,affecting the structural performance and functionality of civil infrastructure systems.Significant efforts have been made to incorporate risk and resilience assessment frameworks into informed decision making to decide how to best use resources to minimize the impact of hazards on civil infrastructure systems.This review paper is part of these efforts.It presents an overview of the main principles and concepts,methods and strategies,advances and accomplishments in the field of life-cycle reliability,risk and resilience of structures and infrastructure systems,with emphasis on seismic resilience of bridges and road networks.展开更多
This paper presents an experimental study of the seismic response of a 0.6-scale three-story seismicresistant building structure consisting of a moment resisting frame （MRF） with reduced beam sections （RBS）, and a...This paper presents an experimental study of the seismic response of a 0.6-scale three-story seismicresistant building structure consisting of a moment resisting frame （MRF） with reduced beam sections （RBS）, and a frame with nonlinear viscous dampers and associated bracing （called the DBF）. The emphasis is on assessing the seismic performance for the design basis earthquake （DBE） and maximum considered earthquake （MCE）. Three MRF designs were studied, with the MRF designed for 100%, 75%, and 60%, respectively, of the required base shear design strength determined according to ASCE 7-10. The DBF with nonlinear viscous dampers was designed to control the lateral drift demands. Earthquake simulations using ensembles of DBE and MCE ground motions were conducted using the real-time hybrid simulation method. The results show the drift demand and damage that occurs in the MRF under seismic loading. Overall, the results show that a high level of seismic performance can be achieved under DBE and MCE ground motions, even for a building structure designed for as little as 60% of the base shear design strength required by ASCE 7-10 for a structure without dampers.展开更多
Real-time testing provides a viable experimental technique to evaluate the performance of structural systems subjected to dynamic loading.Servo-hydraulic actuators are often utilized to apply calculated displacements ...Real-time testing provides a viable experimental technique to evaluate the performance of structural systems subjected to dynamic loading.Servo-hydraulic actuators are often utilized to apply calculated displacements from an integration algorithm to the experimental structures in a real-time manner.The compensation of actuator delay is therefore critical to achieve stable and reliable experimental results.The advances in compensation methods based on adaptive control theory enable researchers to accommodate variable actuator delay and achieve good actuator control for real-time tests.However,these adaptive methods all require time duration for actuator delay adaptation.Experiments show that a good actuator delay estimate can help optimize the performance of the adaptive compensation methods.The rate of adaptation also requires that a good actuator delay estimate be acquired especially for the tests where the peak structural response might occur at the beginning of the tests.This paper presents a model reference adaptive control based method to identify the parameter of a simplified discrete model for servo-hydraulic dynamics and the resulting compensation method.Simulations are conducted using both numerical analysis and experimental results to evaluate the effectiveness of the proposed estimation method.展开更多
文摘Risk assessment and mitigation programs have been carried out over the last decades in the attempt to reduce transportation infrastructure downtime and post-disaster recovery costs.Recently,the concept of resilience gained increasing importance in design,assessment,maintenance,and rehabilitation structures and infrastructure systems,particularly bridges and transportation networks,exposed to natural and man-made hazards.In the field of disaster mitigation,frameworks have been proposed to provide a basis for development of qualitative and quantitative models quantifying the functionality and resilience at various scales,including components,groups and systems within infrastructure networks and communities.In these frameworks,the effects of aging and environmental aggressiveness must be explicitly considered,affecting the structural performance and functionality of civil infrastructure systems.Significant efforts have been made to incorporate risk and resilience assessment frameworks into informed decision making to decide how to best use resources to minimize the impact of hazards on civil infrastructure systems.This review paper is part of these efforts.It presents an overview of the main principles and concepts,methods and strategies,advances and accomplishments in the field of life-cycle reliability,risk and resilience of structures and infrastructure systems,with emphasis on seismic resilience of bridges and road networks.
文摘This paper presents an experimental study of the seismic response of a 0.6-scale three-story seismicresistant building structure consisting of a moment resisting frame （MRF） with reduced beam sections （RBS）, and a frame with nonlinear viscous dampers and associated bracing （called the DBF）. The emphasis is on assessing the seismic performance for the design basis earthquake （DBE） and maximum considered earthquake （MCE）. Three MRF designs were studied, with the MRF designed for 100%, 75%, and 60%, respectively, of the required base shear design strength determined according to ASCE 7-10. The DBF with nonlinear viscous dampers was designed to control the lateral drift demands. Earthquake simulations using ensembles of DBE and MCE ground motions were conducted using the real-time hybrid simulation method. The results show the drift demand and damage that occurs in the MRF under seismic loading. Overall, the results show that a high level of seismic performance can be achieved under DBE and MCE ground motions, even for a building structure designed for as little as 60% of the base shear design strength required by ASCE 7-10 for a structure without dampers.
文摘Real-time testing provides a viable experimental technique to evaluate the performance of structural systems subjected to dynamic loading.Servo-hydraulic actuators are often utilized to apply calculated displacements from an integration algorithm to the experimental structures in a real-time manner.The compensation of actuator delay is therefore critical to achieve stable and reliable experimental results.The advances in compensation methods based on adaptive control theory enable researchers to accommodate variable actuator delay and achieve good actuator control for real-time tests.However,these adaptive methods all require time duration for actuator delay adaptation.Experiments show that a good actuator delay estimate can help optimize the performance of the adaptive compensation methods.The rate of adaptation also requires that a good actuator delay estimate be acquired especially for the tests where the peak structural response might occur at the beginning of the tests.This paper presents a model reference adaptive control based method to identify the parameter of a simplified discrete model for servo-hydraulic dynamics and the resulting compensation method.Simulations are conducted using both numerical analysis and experimental results to evaluate the effectiveness of the proposed estimation method.
