Comparison of Seismic Response of Ordinary and Base-isolated Structures PDF Download
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 8
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Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 8
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Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 8
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Book Description
Seismic isolation is growing rapidly worldwide as a cost-effective and reliable design strategy for a wide range of critical and important facilities (e.g., hospitals, computer centers, etc.) Shimizu Corporation of Japan has a test facility at Tohoku University in Sendai, Japan. The test facility was constructed in 1986 and has two buildings: one is base isolated and the other is conventionally founded. The buildings are full-size, three-story reinforced concrete structures. The dimensions and construction of the superstructures are identical. For the past several years, Shimizu Corporation has installed a number of different isolation systems in the isolated building at the test facility to study the response of base isolation systems to actual earthquake motions. Argonne National Laboratory (ANL) has been deeply involved in the development of seismic isolation for use in nuclear facilities for the past decade. Using the funding and direction of the US Department of Energy (USDOE), ANL has been developing methodology needed to evaluate the usefulness and effectiveness of seismic isolation for advanced liquid metal-cooled reactors (LMRs). This paper compares the seismic responses of ordinary and base-isolated buildings. Earthquake records of significant importance from April 1989 to September 1991, after the installation of bearings have been analyzed. Numerical simulations of the building responses have been performed and correlated with earthquake observation data. It is hoped that the results of this study will provide guidelines for the future use of isolator bearings for mitigation of earthquake damages.
Author: Prayag J. Sayani
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 168
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Book Description
Current design codes generally use an equivalent linear approach for preliminary design of a seismic isolation system. The equivalent linear approach is based on effective parameters, rather than physical parameters of the system, and may not accurately account for the nonlinearity of the isolation system. The second chapter evaluates an alternative normalized strength characterization against the equivalent linear characterization. Following considerations for evaluation are included: (1) ability to effectively account for variations in ground motion intensity, (2) ability to effectively describe the energy dissipation capacity of the isolation system, and (3) conducive to developing design equations that can be implemented within a code framework. Although current code guidelines specify different seismic performance objectives for fixed-base and isolated buildings, the future of performance-based design will allow user-selected performance objectives, motivating the need for a consistent performance comparison of the two systems. Based on response history analysis to a suite of motions, constant ductility spectra are generated for fixed-base and isolated buildings in chapter three. Both superstructure force (base shear) and deformation demands in base-isolated buildings are lower than in fixed-base buildings responding with identical deformation ductility. To compare the relative performance of many systems or to predict the best system to achieve a given performance objective, a response index is developed and used for rapid prototyping of response as a function of system characteristics. When evaluated for a life safety performance objective, the superstructure design base shear of an isolated building is competitive with that of a fixed-base building with identical ductility, and the isolated building generally has improved response. Isolated buildings can meet a moderate ductility immediate-occupancy objective at low design strengths whereas comparable ductility fixed-base buildings fail to meet the objective. In chapter four and five, the life cycle performance of code-designed conventional and base-isolated steel frame buildings is evaluated using loss estimation methodologies. The results of hazard and structural response analysis for three-story moment resisting frame buildings are presented in this paper. Three-dimensional models for both buildings are created and seismic response is assessed for three scenario earthquakes. The response history analysis results indicate that the performance of the isolated building is superior to the conventional building in the design event. However, for the Maximum Considered Earthquake, the presence of outliers in the response data reduces confidence that the isolated building provides superior performance to its conventional counterpart. The outliers observed in the response of the isolated building are disconcerting and need careful evaluation in future studies.
Author: Azer A. Kasimzade
Publisher: Springer
ISBN: 3319931571
Category : Technology & Engineering
Languages : en
Pages : 361
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Book Description
This book features chapters based on selected presentations from the International Congress on Advanced Earthquake Resistance of Structures, AERS2016, held in Samsun, Turkey, from 24 to 28 October 2016. It covers the latest advances in three widely popular research areas in Earthquake Engineering: Performance-Based Seismic Design, Seismic Isolation Systems, and Structural Health Monitoring. The book shows the vulnerability of high-rise and seismically isolated buildings to long periods of strong ground motions, and proposes new passive and semi-active structural seismic isolation systems to protect against such effects. These systems are validated through real-time hybrid tests on shaking tables. Structural health monitoring systems provide rapid assessment of structural safety after an earthquake and allow preventive measures to be taken, such as shutting down the elevators and gas lines, before damage occurs. Using the vibration data from instrumented tall buildings, the book demonstrates that large, distant earthquakes and surface waves, which are not accounted for in most attenuation equations, can cause long-duration shaking and damage in tall buildings. The overview of the current performance-based design methodologies includes discussions on the design of tall buildings and the reasons common prescriptive code provisions are not sufficient to address the requirements of tall-building design. In addition, the book explains the modelling and acceptance criteria associated with various performance-based design guidelines, and discusses issues such as selection and scaling of ground motion records, soil-foundation-structure interaction, and seismic instrumentation and peer review needs. The book is of interest to a wide range of professionals in earthquake engineering, including designers, researchers, and graduate students.
Author: Armin Masroor Shalmani
Publisher:
ISBN:
Category :
Languages : en
Pages : 254
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Book Description
Seismic isolation offers a simple and direct opportunity to control or even eliminate damage to structures subjected to ground shaking by simultaneously reducing deformations and acceleration demands. A base isolation system decouples the superstructure from the ground resulting in elongation of fundamental period of the structure and reducing the accelerations transferred to superstructure during ground shaking. However, increasing the fundamental period of the structure is mostly accompanied by increased displacement demands. In base isolated structures, this large displacement is concentrated at base level where seismic isolation devices are installed and designed to handle these large deformations without damage. A typical base isolated basement design requires a space in which the building is free to move sideways without hitting the surrounding structure. This space is commonly referred to as the "moat". Structural design codes such as ASCE 7-05 that regulate the design of buildings incorporating seismic base isolation systems require the minimum moat wall clearance distance equal to the maximum displacement at the base of the structure under the Maximum Considered Earthquake (MCE), although the superstructure is designed for design basis earthquake (DBE) level. Despite the cautious regulation for moat wall gap distance, pounding of base isolated buildings to moat walls has been reported in previous earthquakes. In conventional structures, the pounding problem between adjacent structures of buildings and highway bridges has been a major cause of seismic damage, even collapse, during earthquakes in the past several decades. Current design specifications may not adequately account for the large forces generated during impact in base isolated buildings. This study investigates the pounding phenomenon in base isolated buildings from both experimental and analytical perspectives by conducting shake table pounding experiments, developing effective models for impact to moat walls and evaluating the adequacy of code specifications for the gap distance of moat walls. A series of prototype base isolated moment and braced buildings designed by professional engineers for the purpose of this project is presented and one of the models was selected for a quarter scale shake table test with moat walls. The pounding experiments indicate that the contact forces generated during pounding can induce yielding in the superstructure and amplify the response acceleration at all stories of the building. The response amplification and damage depends on the gap distance, moat wall properties, and impact velocity. A detailed finite element model of the test setup is developed in OpenSees. An analytical study on the dynamic behavior of the moat walls resulted in proposing a new impact element. Numerical simulation using the proposed impact element compares well with experimental results. A series of collapse studies using the Methodology in FEMA P695 was conducted for both prototype models at various gap distances. The collapse probability of base isolated models used in this study and the effect of moat wall gap distance on the probability of collapse for base isolated structures is investigated. These studies verify that pounding to moat walls at the required gap distance by ASCE7-05 result in acceptable probability of collapse for the flexible and ductile moment frame models examined. However, the braced frame shows a notable drop in collapse margin ratio because of pounding to moat wall at the required gap distance and requires increasing the gap distance by 17%. to have an acceptable collapse probability.
Author: Masahiko Higashino
Publisher: Routledge
ISBN: 113422480X
Category : Business & Economics
Languages : en
Pages : 414
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Book Description
This state of the art report from an international task group (TG44) of CIB, the International Council of Building Research Organizations, presents a highly authoritative guide to the application of innovative technologies on response control and seismic isolation of buildings to practice worldwide. Many countries and cities are located in earthquake-prone areas making effective seismic design a major issue in structural engineering. Reassuringly, structural response control and seismic isolation have advanced remarkably in recent years following numerous studies internationally. Several major conferences have been held and reports have been written but little has been issued on the application of the technologies to good structural engineering practice. Plugging that gap, Response Control and Seismic Isolation of Buildings presents researchers in structural engineering (dynamics) and construction management with up-to-date applications of the latest technologies.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 7
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Book Description
Seismic isolation is gaining attention worldwide for use in a wide spectrum of structures and critical facilities, including bridges, office buildings, hospitals, computing and telecommunication centers, as well as nuclear facilities. Today there are over 125 structures worldwide which are isolated and the numbers have been increasing steadily in the past few years. Also, substantial research efforts have been devoted to the designs, testing of isolation bearings, as well as development of analytical methods for predicting the responses of isolated structures. At Argonne National Laboratory (ANL), a 3-D computer program SISEC (Seismic Isolation System Evaluation Code) is being developed for simulating the system response of isolated and ordinary structures (Wang et al. 1991). This paper describes comparison of SISEC code simulations with building response data of actual earthquakes. To ensure the accuracy of analytical simulations, recorded data of full-size reinforced concrete structures located in Sendai, Japan are used in this benchmark comparison. The test structures consist of two three-story buildings, one base-isolated and the other one ordinary founded. They were constructed side by side to investigate the effect of base isolation on the acceleration response. Among 20 earthquakes observed since April 1989, complete records of three representative earthquakes, Nos. 2, 6, and 17, are used for the code validation presented in this paper. Correlations of observed and calculated accelerations at all instrument locations are made. Also, relative response characteristics of ordinary and isolated building structures are investigated. 3 refs., 5 figs., 1 tab.
Author: Faming Huang
Publisher: Frontiers Media SA
ISBN: 2832531024
Category : Science
Languages : en
Pages : 527
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Book Description
Author: Constantin Christopoulos
Publisher:
ISBN: 9788885701106
Category : Technology & Engineering
Languages : en
Pages :
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Author: Manish Shrikhande
Publisher: Springer Nature
ISBN: 9819916089
Category : Science
Languages : en
Pages : 769
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Book Description
This book presents select proceedings of the 17th Symposium on Earthquake Engineering organized by the Department of Earthquake Engineering, Indian Institute of Technology Roorkee. The topics covered in the proceedings include engineering seismology and seismotectonics, earthquake hazard assessment, seismic microzonation and urban planning, dynamic properties of soils and ground response, ground improvement techniques for seismic hazards, computational soil dynamics, dynamic soil–structure interaction, codal provisions on earthquake-resistant design, seismic evaluation and retrofitting of structures, earthquake disaster mitigation and management, and many more. This book also discusses relevant issues related to earthquakes, such as human response and socioeconomic matters, post-earthquake rehabilitation, earthquake engineering education, public awareness, participation and enforcement of building safety laws, and earthquake prediction and early warning system. This book is a valuable reference for researchers and professionals working in the area of earthquake engineering.
