The Oxford Handbook of Non-Synoptic Wind Storms, 2020
The mechanics associated with thunderstorm outflows differ significantly from traditional turbule... more The mechanics associated with thunderstorm outflows differ significantly from traditional turbulence in boundary layer winds both in its kinematics and dynamics. The key distinguishing attributes are the contrasting velocity profile with height, a rapid increase in speed, and the statistical features of the energetic gusts in the wind field, exhibiting a strong non-stationarity. This raises serious questions regarding the applicability of conventional stationary process-based theories, thus calling for a paradigm shift. This chapter reviews popular approaches concerning the structural analysis of non-stationary thunderstorm outflows, such as evolutionary power spectrum-based analysis, wavelet-based analysis, thunderstorm response spectrum technique involving the equivalent wind spectrum, and hybrid simulation-based analysis in the time domain. Finally, some preliminary comparisons between the results obtained using these different methods are presented.
최근 각광받고 있는 정보 기술은 급속도로 발달하고 있는 인터넷을 기반으로 컴퓨터 분야뿐만 아니라 여러 다른분야에서도 점차 확산되어가고 있다. 인터넷은 네트워크가 지원되는 곳이... more 최근 각광받고 있는 정보 기술은 급속도로 발달하고 있는 인터넷을 기반으로 컴퓨터 분야뿐만 아니라 여러 다른분야에서도 점차 확산되어가고 있다. 인터넷은 네트워크가 지원되는 곳이라면 시간 및 장소에 구애받지 않고 전세계를 하나로 묶을 수 있는 빠르고 간편한 수단이며 공학분야에서도 이를 이용한 새로운 연구방안이 모색되고 있는 실정이다. 본 연구에서는 이러한 인터넷 기술 응용의 일환으로 토목/건축분야에서 최근 널리 사용되는 실제 구조물의 감시/측정을 통해 얻어지는 수많은 데이터를 온라인상으로 처리 하는 방안에 대하여 논의하고자 한다. 이를 위하여 웹서버, 로그인 시스템, 사용자 웹 인터페이스 및 온라인 처리 인터페이스 등을 구축하였으며 현재 실제로 운영중에 있다. 본 연구에서 제안된 온라인 데이터 처리 시스템은 인터넷 기술을 이용하여 전 세계의 연구자들을 대상으로 시간적, 공간적 제약에 비교적 자유롭게 온라인 상으로 데이터를 처리하는 것을 목적으로 하므로 새로운 또는 기존 설계방법의 문제점들을 해결할 수 있는 건설기술들이 발달하는데 여러 면에서 도움을 줄 수 있을 것이다. 또한 이 분야에 관심있는 연구자가 앞으로 각각의 연구목적 및 응용체 적합한 온라인 시스템을 구성을 하는데 있어 본 연구자료가 도움이 될 수 있을 것으로 기대한다.
The frequency domain analysis concerning the response of cascade-nested multiple input/output sys... more The frequency domain analysis concerning the response of cascade-nested multiple input/output systems requires computation of the cross-spectral density matrix involving the input, intermediate and output vectors. This feature lessens the attractiveness of the frequency domain analysis. In this study, a stochastic decomposition technique has been developed which eliminates the need for estimating the cross-spectral density matrix. Central to this technique is the decomposition of a set of correlated random processes into a number of component random sub-processes. Statistically any two decomposed processes are either fully coherent or noncoherent. A random sub-process is expressed in terms of a decomposed spectrum or bi-spectrum. This paper presents a theoretical basis for this approach by utilizing examples.
The DesignSafe cyberinfrastructure (www.designsafe-ci.org) is part of the NSF-funded Natural Haza... more The DesignSafe cyberinfrastructure (www.designsafe-ci.org) is part of the NSF-funded Natural Hazard Engineering Research Infrastructure (NHERI) and provides cloud-based tools to manage, analyze, understand, and publish critical data for research to understand the impacts of natural hazards. The DesignSafe Data Depot provides private and public disk space to support research collaboration and data publishing through a web interface. The DesignSafe Reconnaissance Portal uses a map interface to provide easy access to data collected to investigate the effects of natural hazards, and the DesignSafe Workspace provides cloud-based tools for simulation, data analytics, and visualization; as well as access to high performance computing (HPC). This paper provides an overview of the DesignSafe cyberinfrastructure and describes specific examples of the use of DesignSafe in research for natural hazards. These examples include electronic data reports that use Jupyter notebooks to allow researcher...
AbstractPinnacles on top of tall buildings are vulnerable to vortex-induced vibrations (VIVs). Th... more AbstractPinnacles on top of tall buildings are vulnerable to vortex-induced vibrations (VIVs). These structures may undergo large-amplitude vibrations that can lead to fatigue damage accumulation. ...
The Structural Design of Tall and Special Buildings, 2020
SummaryThis study presents an advanced experimental system, hardware‐in‐the‐loop (HIL), recently ... more SummaryThis study presents an advanced experimental system, hardware‐in‐the‐loop (HIL), recently referred to as hybrid testing, to validate the effectiveness of a double‐decker tuned sloshing damper (TSD) system with screens applied to a recently constructed tall building. The HIL simulation facilitates a performance analysis of a combined structure‐damper system in which the nonlinear behavior of liquid motion in a TSD is physically modeled, whereas a building system under wind loads that behaves linearly is embedded virtually utilizing a computer model. The scaled model of the TSD is composed of a computer‐controlled system with a shaking table, sensors, and a real‐time communication link. The virtual building system on the computer communicates in real time with the hardware, that is, the physical model of TSD to evaluate on‐the‐fly the performance of a combined building‐TSD system. External excitation including random loading characteristics of winds, waves, or earthquakes can b...
Frontiers of Structural and Civil Engineering, 2012
A brief overview of vortex-induced vibration (VIV) of circular cylinders is first given as most o... more A brief overview of vortex-induced vibration (VIV) of circular cylinders is first given as most of VIV studies have been focused on this particular bluff cross-section. A critical literature review of VIV of bridge decks that highlights physical mechanisms central to VIV from a renewed perspective is provided. The discussion focuses on VIV of bridge decks from wind-tunnel experiments, full-scale observations, semi-empirical models and computational fluids dynamics (CFD) perspectives. Finally, a recently developed reduced order model (ROM) based on truncated Volterra series is introduced to model VIV of long-span bridges. This model captures successfully salient features of VIVat “lockin” and unlike most phenomenological models offers physical significance of the model kernels.
AbstractThis paper investigates statistical errors in the simulation of spatially varying seismic... more AbstractThis paper investigates statistical errors in the simulation of spatially varying seismic ground motions modeled by evolutionary Gaussian vector processes and simulated by the spectral repr...
Geotechnical and Structural Engineering Congress 2016, 2016
The current prescriptive design philosophy that relies simply on meeting requirements stipulated ... more The current prescriptive design philosophy that relies simply on meeting requirements stipulated in standards is shifting towards a performance-based design (PBD) approach for achieving designs that rationally meet society\u2019s need for a truly safe built environment. Extensive research has facilitated the successful adoption of PBD in earthquake engineering, but the same cannot be said for wind engineering. Therefore, the need exists to initiate a similar effort by defining a framework that fully embraces the concepts of PBD during the design of building systems to resist severe wind events. This paper illustrates the development of such a PBD framework. In particular, a method is proposed specifically for multi-story wind excited buildings in order to mitigate structural and non-structural damage and loss. In particular, the post-yield behavior of the structural system is modeled using the theory of dynamic shakedown, therefore providing a full portrait of the post-yield behavior without the need for computationally expensive non-linear finite element models. A case study is presented illustrating the practicality of the proposed PBD framework
The Oxford Handbook of Non-Synoptic Wind Storms, 2020
The mechanics associated with thunderstorm outflows differ significantly from traditional turbule... more The mechanics associated with thunderstorm outflows differ significantly from traditional turbulence in boundary layer winds both in its kinematics and dynamics. The key distinguishing attributes are the contrasting velocity profile with height, a rapid increase in speed, and the statistical features of the energetic gusts in the wind field, exhibiting a strong non-stationarity. This raises serious questions regarding the applicability of conventional stationary process-based theories, thus calling for a paradigm shift. This chapter reviews popular approaches concerning the structural analysis of non-stationary thunderstorm outflows, such as evolutionary power spectrum-based analysis, wavelet-based analysis, thunderstorm response spectrum technique involving the equivalent wind spectrum, and hybrid simulation-based analysis in the time domain. Finally, some preliminary comparisons between the results obtained using these different methods are presented.
최근 각광받고 있는 정보 기술은 급속도로 발달하고 있는 인터넷을 기반으로 컴퓨터 분야뿐만 아니라 여러 다른분야에서도 점차 확산되어가고 있다. 인터넷은 네트워크가 지원되는 곳이... more 최근 각광받고 있는 정보 기술은 급속도로 발달하고 있는 인터넷을 기반으로 컴퓨터 분야뿐만 아니라 여러 다른분야에서도 점차 확산되어가고 있다. 인터넷은 네트워크가 지원되는 곳이라면 시간 및 장소에 구애받지 않고 전세계를 하나로 묶을 수 있는 빠르고 간편한 수단이며 공학분야에서도 이를 이용한 새로운 연구방안이 모색되고 있는 실정이다. 본 연구에서는 이러한 인터넷 기술 응용의 일환으로 토목/건축분야에서 최근 널리 사용되는 실제 구조물의 감시/측정을 통해 얻어지는 수많은 데이터를 온라인상으로 처리 하는 방안에 대하여 논의하고자 한다. 이를 위하여 웹서버, 로그인 시스템, 사용자 웹 인터페이스 및 온라인 처리 인터페이스 등을 구축하였으며 현재 실제로 운영중에 있다. 본 연구에서 제안된 온라인 데이터 처리 시스템은 인터넷 기술을 이용하여 전 세계의 연구자들을 대상으로 시간적, 공간적 제약에 비교적 자유롭게 온라인 상으로 데이터를 처리하는 것을 목적으로 하므로 새로운 또는 기존 설계방법의 문제점들을 해결할 수 있는 건설기술들이 발달하는데 여러 면에서 도움을 줄 수 있을 것이다. 또한 이 분야에 관심있는 연구자가 앞으로 각각의 연구목적 및 응용체 적합한 온라인 시스템을 구성을 하는데 있어 본 연구자료가 도움이 될 수 있을 것으로 기대한다.
The frequency domain analysis concerning the response of cascade-nested multiple input/output sys... more The frequency domain analysis concerning the response of cascade-nested multiple input/output systems requires computation of the cross-spectral density matrix involving the input, intermediate and output vectors. This feature lessens the attractiveness of the frequency domain analysis. In this study, a stochastic decomposition technique has been developed which eliminates the need for estimating the cross-spectral density matrix. Central to this technique is the decomposition of a set of correlated random processes into a number of component random sub-processes. Statistically any two decomposed processes are either fully coherent or noncoherent. A random sub-process is expressed in terms of a decomposed spectrum or bi-spectrum. This paper presents a theoretical basis for this approach by utilizing examples.
The DesignSafe cyberinfrastructure (www.designsafe-ci.org) is part of the NSF-funded Natural Haza... more The DesignSafe cyberinfrastructure (www.designsafe-ci.org) is part of the NSF-funded Natural Hazard Engineering Research Infrastructure (NHERI) and provides cloud-based tools to manage, analyze, understand, and publish critical data for research to understand the impacts of natural hazards. The DesignSafe Data Depot provides private and public disk space to support research collaboration and data publishing through a web interface. The DesignSafe Reconnaissance Portal uses a map interface to provide easy access to data collected to investigate the effects of natural hazards, and the DesignSafe Workspace provides cloud-based tools for simulation, data analytics, and visualization; as well as access to high performance computing (HPC). This paper provides an overview of the DesignSafe cyberinfrastructure and describes specific examples of the use of DesignSafe in research for natural hazards. These examples include electronic data reports that use Jupyter notebooks to allow researcher...
AbstractPinnacles on top of tall buildings are vulnerable to vortex-induced vibrations (VIVs). Th... more AbstractPinnacles on top of tall buildings are vulnerable to vortex-induced vibrations (VIVs). These structures may undergo large-amplitude vibrations that can lead to fatigue damage accumulation. ...
The Structural Design of Tall and Special Buildings, 2020
SummaryThis study presents an advanced experimental system, hardware‐in‐the‐loop (HIL), recently ... more SummaryThis study presents an advanced experimental system, hardware‐in‐the‐loop (HIL), recently referred to as hybrid testing, to validate the effectiveness of a double‐decker tuned sloshing damper (TSD) system with screens applied to a recently constructed tall building. The HIL simulation facilitates a performance analysis of a combined structure‐damper system in which the nonlinear behavior of liquid motion in a TSD is physically modeled, whereas a building system under wind loads that behaves linearly is embedded virtually utilizing a computer model. The scaled model of the TSD is composed of a computer‐controlled system with a shaking table, sensors, and a real‐time communication link. The virtual building system on the computer communicates in real time with the hardware, that is, the physical model of TSD to evaluate on‐the‐fly the performance of a combined building‐TSD system. External excitation including random loading characteristics of winds, waves, or earthquakes can b...
Frontiers of Structural and Civil Engineering, 2012
A brief overview of vortex-induced vibration (VIV) of circular cylinders is first given as most o... more A brief overview of vortex-induced vibration (VIV) of circular cylinders is first given as most of VIV studies have been focused on this particular bluff cross-section. A critical literature review of VIV of bridge decks that highlights physical mechanisms central to VIV from a renewed perspective is provided. The discussion focuses on VIV of bridge decks from wind-tunnel experiments, full-scale observations, semi-empirical models and computational fluids dynamics (CFD) perspectives. Finally, a recently developed reduced order model (ROM) based on truncated Volterra series is introduced to model VIV of long-span bridges. This model captures successfully salient features of VIVat “lockin” and unlike most phenomenological models offers physical significance of the model kernels.
AbstractThis paper investigates statistical errors in the simulation of spatially varying seismic... more AbstractThis paper investigates statistical errors in the simulation of spatially varying seismic ground motions modeled by evolutionary Gaussian vector processes and simulated by the spectral repr...
Geotechnical and Structural Engineering Congress 2016, 2016
The current prescriptive design philosophy that relies simply on meeting requirements stipulated ... more The current prescriptive design philosophy that relies simply on meeting requirements stipulated in standards is shifting towards a performance-based design (PBD) approach for achieving designs that rationally meet society\u2019s need for a truly safe built environment. Extensive research has facilitated the successful adoption of PBD in earthquake engineering, but the same cannot be said for wind engineering. Therefore, the need exists to initiate a similar effort by defining a framework that fully embraces the concepts of PBD during the design of building systems to resist severe wind events. This paper illustrates the development of such a PBD framework. In particular, a method is proposed specifically for multi-story wind excited buildings in order to mitigate structural and non-structural damage and loss. In particular, the post-yield behavior of the structural system is modeled using the theory of dynamic shakedown, therefore providing a full portrait of the post-yield behavior without the need for computationally expensive non-linear finite element models. A case study is presented illustrating the practicality of the proposed PBD framework
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