The Implementation of a Versatile Pseudodynamic Hybrid Simulation for Seismic Evaluation of Structural Systems PDF Download
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Author: Chelsea Griffith
Publisher:
ISBN:
Category : Structural engineering
Languages : en
Pages : 144
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Book Description
Pseudodynamic hybrid simulation technique was developed to evaluate structural seismic performance by physically testing the critical portion with the remaining structure simulated using a numerical model in the computer. An incremental approach was adopted in developing the control scheme to suit multiple testing facilities and test specimens. First the small scale, predictable specimen was utilized to investigate techniques of improving stability, slowing down the loading rate and triggering the accurate force measurement in a series of at benchmark scale experiments in the Laboratory of Earthquake and Structural Simulation at Western Michigan University (WMU). A step/hold command scheme was developed and results matched well to those obtained from the purely numerical simulations of the analytical model setup based on the cyclic tests. Then a series of open and closed loop PSD hybrid simulations of increasing amplitude were conducted at large scale in the Structural Engineering Laboratory at University of Alabama. A ramp/hold displacement command scheme with flexible definition on the ramp phase were developed to the address the excessive vibrations due to the very high speed actuator. The final control scheme was applied the large scale PSD hybrid simulation of a two story wood frame building with a physical first story wood shear wall and numerical second story and reasonable seismic response were achieved. The results of this study serve as a basis for developing the simulation technique for the large scale hybrid simulation that that will be conducted at the NEES equipment site at the University of Buffalo.
Author: Chelsea Griffith
Publisher:
ISBN:
Category : Structural engineering
Languages : en
Pages : 144
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Book Description
Pseudodynamic hybrid simulation technique was developed to evaluate structural seismic performance by physically testing the critical portion with the remaining structure simulated using a numerical model in the computer. An incremental approach was adopted in developing the control scheme to suit multiple testing facilities and test specimens. First the small scale, predictable specimen was utilized to investigate techniques of improving stability, slowing down the loading rate and triggering the accurate force measurement in a series of at benchmark scale experiments in the Laboratory of Earthquake and Structural Simulation at Western Michigan University (WMU). A step/hold command scheme was developed and results matched well to those obtained from the purely numerical simulations of the analytical model setup based on the cyclic tests. Then a series of open and closed loop PSD hybrid simulations of increasing amplitude were conducted at large scale in the Structural Engineering Laboratory at University of Alabama. A ramp/hold displacement command scheme with flexible definition on the ramp phase were developed to the address the excessive vibrations due to the very high speed actuator. The final control scheme was applied the large scale PSD hybrid simulation of a two story wood frame building with a physical first story wood shear wall and numerical second story and reasonable seismic response were achieved. The results of this study serve as a basis for developing the simulation technique for the large scale hybrid simulation that that will be conducted at the NEES equipment site at the University of Buffalo.
Author: Gian Paolo Cimellaro
Publisher: Springer
ISBN: 3319063944
Category : Science
Languages : en
Pages : 329
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Book Description
The book is a tribute to the research contribution of Professor Andrei Reinhorn in the field of earthquake engineering. It covers all the aspects connected to earthquake engineering starting from computational methods, hybrid testing and control, resilience and seismic protection which have been the main research topics in the field of earthquake engineering in the last 30 years. These were all investigated by Prof. Reinhorn throughout his career. The book provides the most recent advancements in these four different fields, including contributions coming from six different countries giving an international outlook to the topics.
Author: Victor Saouma
Publisher: CRC Press
ISBN: 1482288613
Category : Computers
Languages : en
Pages : 242
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Book Description
Hybrid Simulation deals with a rapidly evolving technology combining computer simulation (typically finite element) and physical laboratory testing of two complementary substructures. It is a cost effective alternative to shaking table test, and allows for the improved understanding of complex coupled systems. Traditionally, numerical simulation an
Author: Griffin Enyart
Publisher:
ISBN:
Category : Earthquake engineering
Languages : en
Pages : 218
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Book Description
A hybrid testing system was developed to evaluate the seismic performance of a structural system by physically testing part of the structure, called a physical substructure, while numerically simulating the rest of the structure using a computer model. Instead of building a full sized structural specimen, hybrid testing allows researchers to build a complex substructure to be tested experimentally while the relatively simple part of the structure is numerically simulated. A versatile hybrid testing system was developed at Western Michigan University which includes a seismic simulator (often called a shake table), a reaction/loading system and an advanced hybrid testing controller. Such a testing system was used to simulate the seismic response of a three story structure whose top story was installed with motion mitigation devices (i.e.: dampers). The physical substructure is the top story with damper, which was installed on the shake table, and the numerical substructure is the lower two stories simulated in the computer. The boundry motions between the physical and numerical substructure were numerically simulated and applied to the top story using the shake table. Test results as well as the development of the test system were presented and discussed in this thesis.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 271
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Book Description
The increased need for experimental verification of the seismic performance of conventional and novel structural systems has resulted in highly sophisticated dynamic test procedures. Hybrid simulation, including pseudo-dynamic testing of experimental substructures, offers an efficient method for assessment of dynamic and rate-dependent behavior of large-scale structural systems subjected to earthquake excitation. Compared to earthquake simulations using shake tables, hybrid simulation may have significant advantages in terms of cost, scale, geometry, and required physical mass of structures and components that can be tested. However, recent hybrid simulations have been limited to simplified structural models with only a few degrees of freedom. This is primarily due to the fact that hybrid simulation is a relatively new test method that is still being improved through research. Currently, the major challenges for using hybrid simulation in large and complex structural systems are the lack of robust simulation algorithms, and the sensitivity of the results to experimental errors in the presence of high-frequency modes. The main motivation for this research is to develop reliable test procedures that can be easily applied to fast and real-time hybrid simulations of large and complex structural systems. It is also attempted to develop test procedures that are effective for geographically distributed hybrid simulations. In this dissertation, recent developments to improve the accuracy and stability of hybrid simulation are described using the state-of-the-art pseudo-dynamic hybrid simulation system at the Structural Engineering and Earthquake Simulation Laboratory, University at Buffalo. In particular, delay compensation procedures are examined, and new methods are proposed. These methods are based on the correction of tracking errors in force measurement signal, and using the numerical integration procedure for prediction and compensation of command displacement signal. A new online procedure is proposed for estimation of delay during the simulation, and is shown to have better performance compared to existing online delay estimation methods. Furthermore, two numerical integration procedures are introduced for hybrid simulation, which are shown to improve the stability and accuracy properties of the simulation. The proposed integration algorithms use experimental measurements to iterate within implicit scheme and also take advantage of a new approach to estimate the tangent stiffness matrix of experimental substructures. For assessment of the reliability of hybrid simulation results, energy-based error monitors are proposed to examine the severity of experimental and numerical errors. These measures are then used to demonstrate the improved accuracy offered by new algorithms proposed here through analytical and numerical studies, and numerical and experimental simulations.
Author: Georgios Giotis
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Hybrid simulation methods have attracted significant interest from researchers in structural engineering to accurately assess the seismic performance of structures. To implement hybrid simulations in a testing facility, it is necessary to properly control the boundary conditions of physically tested specimens. The objective of this study is to propose and implement a methodology for performing hybrid simulations when a limited number of actuators are available and the full control of the boundary conditions is not possible. The developed methodology is employed to evaluate the seismic performance of a RC structure where one of the first storey columns is experimentally tested with testing equipment which can control only two DOF instead of the three required for columns subjected to planar motions. The seismic assessment is performed for the cases of an intact, repaired and retrofitted structure, where externally applied Carbon Fiber Reinforced Polymer (CFRP) fabric is used for repairing and retrofitting.
Author: Saeid Mojiri
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
This study presents a 10-element hybrid (experimental-numerical) simulation platform, referred to as UT10, which was developed for running pseudo-dynamic hybrid simulations of braced frames with up to 10 large-capacity physical brace specimens. This study presents the details of the development of different components of UT10 including a network interface for actuator controller, NICON-10. An adjustable brace specimen, referred to as Adjustable Yielding Brace (AYB), was designed to simulate the hysteretic response of yielding braces such as buckling-restrained braces (BRBs) thus facilitating the seismic performance evaluation of multi-storey structures with hysteretic energy dissipative braces through hybrid simulations. Also, a buckling specimen was designed to simulate the hysteretic response of conventional buckling braces. Both AYB and buckling specimens were cyclically tested in UT10. The results indicated that these specimens are capable of producing hysteretic responses with characteristics similar to BRBs and conventional braces. A five-storey buckling-restrained braced frame (BRBF) and a special concentrically braced frame (SCBF) were designed and tested, respectively, with AYB specimens and buckling specimens representing the braces. Cyclic tests of the AYB and buckling specimens, 1- and 3-element hybrid simulations of the BRBF, and 2- and 4-element hybrid simulations of the SCBF inside UT10 confirmed the functionality of UT10 for running hybrid simulations on multiple specimens. Comparison of the results of the hybrid simulations of the BRBF and SCBF with their fully numerical models showed that the modelling inaccuracies of the yielding braces could affect the global response of the multi-storey braced frames further emphasizing the need for experimental calibration or hybrid simulation for achieving more accurate response predictions. UT10 provides a simple and reconfigurable platform that can be used to achieve a realistic understanding of the seismic response of multi-storey frames with yielding braces, distinguish their modelling limitations, and improve different modelling techniques available for their seismic response prediction.
Author: Catherine Alexandra Whyte
Publisher:
ISBN:
Category :
Languages : en
Pages : 442
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Book Description
Most industrial and nuclear facilities rely on reinforced concrete structural walls as their primary seismic lateral-force-resisting components. These walls commonly have an aspect ratio smaller than 0.5 and have a very high stiffness and strength. There is a significant uncertainty regarding the behavior of these walls under earthquake loading, their failure modes, and their expected strengths and deformation capacities. Hybrid simulation is an effective experimental method to examine these issues: it enables simulation of the seismic response of squat and thick shear walls without the need to recreate the, often very large, mass associated with the rest of the prototype structure. A new method for hybrid simulation of the earthquake response of stiff specimens using a high-precision displacement encoder was developed and verified in this study. This method was implemented for hybrid simulation of seismic response of two large-scale squat reinforced concrete shear walls. In order to examine the response of squat reinforced concrete walls to earthquake ground motion and to investigate the effect of ground motion sequence, two nominally identically 8 in thick models of a prototype 36 in thick structural wall, typically found in nuclear facility structures, were tested. Each wall experienced a different ground motion level loading sequence. After an initial combined shear and flexural response, a sliding shear failure occurred at the base of the walls. This response was quasi-brittle: the walls rapidly lost strength with small increments of post-peak strength deformation. A nominally identical specimen was tested at the State University of New York at Buffalo. Though the quasi-static cyclic test method has been shown to accurately predict the seismic failure modes of ductile, often flexure-dominated, specimens, there is considerable uncertainty associated with the predictive ability of the quasi-static cyclic test method when the tested specimens have brittle or quasi-brittle failure modes. In these cases, the effect of load magnitude history is so significant that it alters the deformation demand and the sequence of seismic failure modes. The quasi-static cyclic test at Buffalo was compared to the hybrid seismic response simulation experiments at Berkeley to evaluate its effectiveness with capturing the wall response to ground motion sequences. The findings from the hybrid simulation tests were that displacement control hybrid simulation using a high-precision encoder for displacement feedback is an effective way to perform large-scale hybrid tests of stiff specimens. This new method is useful to address the shortcomings with understanding the dynamic behavior of these types of specimens. The results of the two wall hybrid simulation tests indicate that different earthquake magnitude sequences do not have a significant effect on the force-deformation response and the failure mode sequence of squat walls. After comparing the hybrid simulation test results to the quasi-static cyclic test at Buffalo, the quasi-static cyclic test was determined to be adequate for testing the quasi-brittle wall specimens. It effectively captured the global response of the squat shear walls in earthquake ground motion sequences. Comparison of wall response to code based predictive equations showed that the code equations overpredict the peak shear strength of these squat rectangular walls by factors as large as 2. Modifications to code recommendations for the initial stiffness and peak shear strength of these walls are offered, and a definition for the "essentially elastic" region, used in nuclear facility design, is also suggested.
Author: Nigel Powers
Publisher: CRC Press
ISBN: 1351745972
Category : Technology & Engineering
Languages : en
Pages : 550
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Book Description
Maintenance, Safety, Risk, Management and Life-Cycle Performance of Bridges contains lectures and papers presented at the Ninth International Conference on Bridge Maintenance, Safety and Management (IABMAS 2018), held in Melbourne, Australia, 9-13 July 2018. This volume consists of a book of extended abstracts and a USB card containing the full papers of 393 contributions presented at IABMAS 2018, including the T.Y. Lin Lecture, 10 Keynote Lectures, and 382 technical papers from 40 countries. The contributions presented at IABMAS 2018 deal with the state of the art as well as emerging concepts and innovative applications related to the main aspects of bridge maintenance, safety, risk, management and life-cycle performance. Major topics include: new design methods, bridge codes, heavy vehicle and load models, bridge management systems, prediction of future traffic models, service life prediction, residual service life, sustainability and life-cycle assessments, maintenance strategies, bridge diagnostics, health monitoring, non-destructive testing, field testing, safety and serviceability, assessment and evaluation, damage identification, deterioration modelling, repair and retrofitting strategies, bridge reliability, fatigue and corrosion, extreme loads, advanced experimental simulations, and advanced computer simulations, among others. This volume provides both an up-to-date overview of the field of bridge engineering and significant contributions to the process of more rational decision-making on bridge maintenance, safety, risk, management and life-cycle performance of bridges for the purpose of enhancing the welfare of society. The Editors hope that these Proceedings will serve as a valuable reference to all concerned with bridge structure and infrastructure systems, including students, researchers and engineers from all areas of bridge engineering.
Author: Wei Song
Publisher: Frontiers Media SA
ISBN: 2889663809
Category : Technology & Engineering
Languages : en
Pages : 213
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Book Description
