Ting-Yu Hsu | Bb - Academia.edu (original) (raw)
Papers by Ting-Yu Hsu
Natural Hazards Review, 2019
The method of on-site earthquake early warning was proposed in the past decade to enhance seismic... more The method of on-site earthquake early warning was proposed in the past decade to enhance seismic preparedness and safety measures for areas close to the earthquake epicenter. The method leverages critical information contained in the initial 3 s of a P wave that arrives early to predict possibly intense ground shaking at a site. In this study, two types of empirical relationships are developed: (1) Pd 3-PGV relationship for predicting the horizontal peak ground velocity (PGV) based on the peak displacement in the first 3 s of the vertical motion (Pd 3); and (2) τ c − M w relationship for estimating the moment magnitude (Mw) of an earthquake based on a groundmotion period parameter (τ c). Performance of these empirical relationships in on-site earthquake early warning framework is examined using global earthquake records from the most updated Next Generation Attenuation (NGA-West2) strong-motion database. Region-specific empirical predictive equations for California and Japan are proposed based on the state of the art mixed-effect regression to separate ground-motion variability between different earthquakes and that within an earthquake. Applicability and inapplicability of the empirical models in the near-fault condition are investigated using ground motions with strong velocity pulses. The overarching goal of study is to leverage the comprehensive database and state of the art regression techniques to facilitate understanding and engineering practice of on-site earthquake early warning in a variety of regions and in the near-fault condition.
Journal of Engineering Mechanics-asce, 2008
A modified modal strain energy change (M-MSEC) method and its corresponding iteration process are... more A modified modal strain energy change (M-MSEC) method and its corresponding iteration process are presented to detect damage of frame structures. It improves that the damage quantification obtained by using different kind of modes in M-MSEC can be identified correctly. The effectiveness of the proposed algorithm is demonstrated via numerical study of a 3-D frame structure. A full scale experimental study is also performed to evaluate the robustness of the M-MSEC method on damage detection. Satisfactory results are shown in relating to the modeling error, noise effect and limited measurements.
Smart Materials & Structures, 2011
In this paper, a wireless sensing system is designed to realize on-line damage localization and q... more In this paper, a wireless sensing system is designed to realize on-line damage localization and quantification of a structure using a frequency response function change method (FRFCM). Data interrogation algorithms are embedded in the computational core of the wireless sensing units to extract the necessary structural features, i.e. the frequency spectrum segments around eigenfrequencies, automatically from measured structural response for the FRFCM. Instead of the raw time history of the structural response, the extracted compact structural features are transmitted to the host computer. As a result, with less data transmitted from the wireless sensors, the energy consumed by the wireless transmission is reduced. To validate the performance of the proposed wireless sensing system, a six-story steel building with replaceable bracings in each story is instrumented with the wireless sensors for on-line damage detection during shaking table tests. The accuracy of the damage detection results using the wireless sensing system is verified through comparison with the results calculated from data recorded of a traditional wired monitoring system. The results demonstrate that, by taking advantage of collocated computing resources in wireless sensors, the proposed wireless sensing system can locate and quantify damage with acceptable accuracy and moderate energy efficiency.
Structural Control & Health Monitoring, 2009
Damage detection in structural health monitoring should accommodate the variation caused by varyi... more Damage detection in structural health monitoring should accommodate the variation caused by varying environmental conditions such as temperature, humidity, loading, and boundary conditions. A structural damage detection technique is proposed to deal with the continuous monitoring data of a structural system subjected to the complex nonlinear behavior caused by varying environmental conditions. Based on the identified or measured target features of the structural system under varying environmental conditions, e.g. stiffness of the structural components, the nonlinear principal component analysis (NLPCA) using auto-associative neural network is performed to extract the underlying environmental factors. Then a prediction model for NLPCA is proposed to estimate the damage extent. This proposed technique is capable of dealing with not only the non-increasing features, e.g. stiffness, but also the non-decreasing features, e.g. damage index, after damage is introduced without measuring the environmental factors directly. A numerical study is performed to demonstrate the advantages of the proposed technique over the technique using principal component analysis. A synthetic bridge model is simulated with the consideration of a specific element stiffness reduction together with the change due to environmental conditions including temperature, gradient of temperature, humidity, and frozen supports. Results show that the extent of stiffness loss can be quantified accurately and promptly after the damage is introduced. Copyright © 2009 John Wiley & Sons, Ltd.
This paper deals with the problem of damage localization and quantification using the Frequency R... more This paper deals with the problem of damage localization and quantification using the Frequency Response Function (FRF) subjected to earthquake ground excitation. The damage identification equation is derived from the motion equation of the system before and after damage. The FRFs of the intact and damaged system as well as the system matrices of the intact system are required to solve the damage identification equation. The system matrices can be obtained from the state matrices identified by subspace identification technique. According to the numerical study of a frame structure, only a few discrete frequencies from the FRFs which are close to the system natural frequencies are sufficient to achieve a satisfactory precision of damage extent. The proposed technique was applied to an experimental data of a 6-story steel frame structure and its efficiency was confirmed.
Journal of Structural Engineering-asce, 2000
Unilateral, bilateral, and triaxial shaking table tests are conducted to study the seismic respon... more Unilateral, bilateral, and triaxial shaking table tests are conducted to study the seismic response of a three-story base-isolated steel structure. The lateral force distribution formulas specified in the Uniform Building Code are evaluated experimentally. A method to calculate the ...
Natural Hazards Review, 2019
The method of on-site earthquake early warning was proposed in the past decade to enhance seismic... more The method of on-site earthquake early warning was proposed in the past decade to enhance seismic preparedness and safety measures for areas close to the earthquake epicenter. The method leverages critical information contained in the initial 3 s of a P wave that arrives early to predict possibly intense ground shaking at a site. In this study, two types of empirical relationships are developed: (1) Pd 3-PGV relationship for predicting the horizontal peak ground velocity (PGV) based on the peak displacement in the first 3 s of the vertical motion (Pd 3); and (2) τ c − M w relationship for estimating the moment magnitude (Mw) of an earthquake based on a groundmotion period parameter (τ c). Performance of these empirical relationships in on-site earthquake early warning framework is examined using global earthquake records from the most updated Next Generation Attenuation (NGA-West2) strong-motion database. Region-specific empirical predictive equations for California and Japan are proposed based on the state of the art mixed-effect regression to separate ground-motion variability between different earthquakes and that within an earthquake. Applicability and inapplicability of the empirical models in the near-fault condition are investigated using ground motions with strong velocity pulses. The overarching goal of study is to leverage the comprehensive database and state of the art regression techniques to facilitate understanding and engineering practice of on-site earthquake early warning in a variety of regions and in the near-fault condition.
Journal of Engineering Mechanics-asce, 2008
A modified modal strain energy change (M-MSEC) method and its corresponding iteration process are... more A modified modal strain energy change (M-MSEC) method and its corresponding iteration process are presented to detect damage of frame structures. It improves that the damage quantification obtained by using different kind of modes in M-MSEC can be identified correctly. The effectiveness of the proposed algorithm is demonstrated via numerical study of a 3-D frame structure. A full scale experimental study is also performed to evaluate the robustness of the M-MSEC method on damage detection. Satisfactory results are shown in relating to the modeling error, noise effect and limited measurements.
Smart Materials & Structures, 2011
In this paper, a wireless sensing system is designed to realize on-line damage localization and q... more In this paper, a wireless sensing system is designed to realize on-line damage localization and quantification of a structure using a frequency response function change method (FRFCM). Data interrogation algorithms are embedded in the computational core of the wireless sensing units to extract the necessary structural features, i.e. the frequency spectrum segments around eigenfrequencies, automatically from measured structural response for the FRFCM. Instead of the raw time history of the structural response, the extracted compact structural features are transmitted to the host computer. As a result, with less data transmitted from the wireless sensors, the energy consumed by the wireless transmission is reduced. To validate the performance of the proposed wireless sensing system, a six-story steel building with replaceable bracings in each story is instrumented with the wireless sensors for on-line damage detection during shaking table tests. The accuracy of the damage detection results using the wireless sensing system is verified through comparison with the results calculated from data recorded of a traditional wired monitoring system. The results demonstrate that, by taking advantage of collocated computing resources in wireless sensors, the proposed wireless sensing system can locate and quantify damage with acceptable accuracy and moderate energy efficiency.
Structural Control & Health Monitoring, 2009
Damage detection in structural health monitoring should accommodate the variation caused by varyi... more Damage detection in structural health monitoring should accommodate the variation caused by varying environmental conditions such as temperature, humidity, loading, and boundary conditions. A structural damage detection technique is proposed to deal with the continuous monitoring data of a structural system subjected to the complex nonlinear behavior caused by varying environmental conditions. Based on the identified or measured target features of the structural system under varying environmental conditions, e.g. stiffness of the structural components, the nonlinear principal component analysis (NLPCA) using auto-associative neural network is performed to extract the underlying environmental factors. Then a prediction model for NLPCA is proposed to estimate the damage extent. This proposed technique is capable of dealing with not only the non-increasing features, e.g. stiffness, but also the non-decreasing features, e.g. damage index, after damage is introduced without measuring the environmental factors directly. A numerical study is performed to demonstrate the advantages of the proposed technique over the technique using principal component analysis. A synthetic bridge model is simulated with the consideration of a specific element stiffness reduction together with the change due to environmental conditions including temperature, gradient of temperature, humidity, and frozen supports. Results show that the extent of stiffness loss can be quantified accurately and promptly after the damage is introduced. Copyright © 2009 John Wiley & Sons, Ltd.
This paper deals with the problem of damage localization and quantification using the Frequency R... more This paper deals with the problem of damage localization and quantification using the Frequency Response Function (FRF) subjected to earthquake ground excitation. The damage identification equation is derived from the motion equation of the system before and after damage. The FRFs of the intact and damaged system as well as the system matrices of the intact system are required to solve the damage identification equation. The system matrices can be obtained from the state matrices identified by subspace identification technique. According to the numerical study of a frame structure, only a few discrete frequencies from the FRFs which are close to the system natural frequencies are sufficient to achieve a satisfactory precision of damage extent. The proposed technique was applied to an experimental data of a 6-story steel frame structure and its efficiency was confirmed.
Journal of Structural Engineering-asce, 2000
Unilateral, bilateral, and triaxial shaking table tests are conducted to study the seismic respon... more Unilateral, bilateral, and triaxial shaking table tests are conducted to study the seismic response of a three-story base-isolated steel structure. The lateral force distribution formulas specified in the Uniform Building Code are evaluated experimentally. A method to calculate the ...