scholarly journals Evaluation of optimal FVDs for inter-storey isolation systems based on surrogate performance models

2021 ◽  
Author(s):  
Marco Donà ◽  
Enrico Bernardi ◽  
Alberto Zonta ◽  
Ping Tan ◽  
Fulin Zhou
Keyword(s):  
Seismic Performance ◽  
Seismic Isolation ◽  
Prediction Models ◽  
Relative Displacement ◽  
Isolation System ◽  
General Validity ◽  
Fluid Viscous Dampers ◽  
Wide Range ◽  
And Performance ◽  
Isolation Systems

AbstractInter-storey seismic isolation is increasingly gaining attention. One of the main related issues is the need to limit the relative displacement between substructure and superstructure, while maintaining a good seismic performance of the superstructure. As shown in some studies, fluid viscous dampers (FVDs) mounted in isolation systems are effective in reducing isolator deflection but can be harmful by amplifying inter-storey drifts and floor accelerations. Additionally, the effectiveness of FVDs for inter-storey applications was investigated only recently, and specific approaches for their optimisation and performance evaluation are missing. Therefore, this paper proposes a method for the optimal multi-objective design of FVDs, based on the definition of appropriate surrogate response models, which allows for rationally comparing the FVD effects for a wide range of dampers and structures. In particular, the optimal FVD parameters are provided in a dimensionless form, so that they can be predicted by design equations of general validity within the range of the structures analysed. This method is applied to a stock of regular structures with various vibration periods of superstructure, isolation and substructure, examining a linear and a non-linear isolation system and a set of natural records, in order to comprehensively assess the effects of FVDs and their non-linearity on the seismic performance of these structures. Finally, prediction models of optimal FVD parameters are provided based on the results obtained and are applied to three case studies as an example.

scholarly journals THE IMPACT OF APPLYING BASE ISOLATOR IN HOSPITAL BUILDING

2014 ◽  
Vol 10 (2) ◽  
pp. 9
Author(s):  
Predaricka Deastra ◽  
Jati Sunaryati ◽  
Riza Aryanti
Keyword(s):  
Seismic Performance ◽  
Seismic Isolation ◽  
Relative Displacement ◽  
Internal Force ◽  
Isolation System ◽  
Vibration Period ◽  
Final Project ◽  
The Difference ◽  
Earthquake Zone ◽  
The Impact

Due to Indonesia’s location in the earthquake zone, it is necessary for civil engineers in Indonesia to study seismic performance of a building, which is strongly related to the structure of the building itself. Buildings equipped with vibration damping structures, known as an isolation system, will have a different seismic behavior than if it did not have one. This is due to the impact of an earthquake dampening vibration isolator. This final project analyzes the difference between seismic performance of a building using a seismic isolation system and ones without. The conclusion of this final project shows that the isolation system will decrease the internal force of a structure element by about 57.71% for axial force, 84.10% for shear, and 85.75% for moment. The application of an isolation system will also decrease the relative displacement by about 74,28% and extended structure vibration period by about 171.17 %. Keywords: earthquake, seismic performance, isolation system.

Seismic Isolation Analysis on Long-Span Platform Bridge Connecting Twin-Tower Structures

2011 ◽  
Vol 255-260 ◽  
pp. 1225-1229
Author(s):  
Huang Sheng Sun ◽  
Li Nuo Cheng ◽  
Shi Hai Chen
Keyword(s):  
Seismic Isolation ◽  
Seismic Responses ◽  
One Pot ◽  
Isolation System ◽  
High Position ◽  
Long Span ◽  
Steel Truss ◽  
Story Drift ◽  
Isolation Systems ◽  
Rubber Bearings

In order to mitigate the seismic response of twin-tower structure linked by a steel truss platform bridge, as well as to reduce temperature force in the steel truss, eight groups of combined isolation system, each consisting of one pot-type bearing and four rubber bearings, were designed to connect the upper platform bridge to the lower supporting reinforced concrete towers. The features and working principles of the high-position isolation system were described. Then the seismic responses, including displacement, story drift and floor acceleration, of the structure with the isolation systems were calculated and compared with those of the structure with hinge joints in lieu of isolation. It is found that both the structural seismic responses and the temperature forces in the large-span mega-truss structure can be reduced by the high-position isolation system.

Analysis of Vibration Isolator’s Anti-Seismic Performance in Porcelain SF6 High Voltage Circuit Breaker

2013 ◽  
Vol 448-453 ◽  
pp. 2045-2048
Author(s):  
Yan Zhong Ju ◽  
Xin Lei Wu
Keyword(s):  
Seismic Performance ◽  
High Voltage ◽  
Seismic Isolation ◽  
Circuit Breaker ◽  
Isolation System ◽  
High Voltage Circuit Breaker ◽  
Rubber Bearing ◽  
Laminated Rubber Bearing ◽  
Sf6 Circuit Breaker ◽  
Isolation Device

Choosing LW15-550Y porcelain high voltage SF6 circuit breaker as the research subject, we designed the lead laminated rubber bearing (LRB) seismic isolation device for LW15-550Y circuit breaker. We finally gets the results that the LRB isolation system increases the flexibility of the breaker structure and improves the seismic performance of the high voltage circuit breaker structure.

Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities: Part 3 — Seismic Response of Crossover Piping for Seismic Isolation System

2014 ◽  
Author(s):  
Akihito Otani ◽  
Teruyoshi Otoyo ◽  
Hideo Hirai ◽  
Hirohide Iiizumi ◽  
Hiroshi Shimizu ◽  
...  
Keyword(s):  
Seismic Response ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Evaluation Method ◽  
Response Spectrum ◽  
Time History ◽  
Response Analysis ◽  
Isolation System ◽  
Isolation Systems ◽  
Seismic Isolation Systems

This paper, which is part of the series entitled “Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities”, shows the linear seismic response of crossover piping installed in a seismically isolated plant. The crossover piping, supported by both isolated and non-isolated buildings, deforms with large relative displacement between the two buildings and the seismic response of the crossover piping is caused by two different seismic excitations from the buildings. A flexible and robust structure is needed for the high-pressure crossover piping. In this study, shaking tests on a 1/10 scale piping model and FEM analyses were performed to investigate the seismic response of the crossover piping which was excited and deformed by two different seismic motions under isolated and non-isolated conditions. Specifically, as linear response analysis of the crossover piping, modal time-history analysis and response spectrum analysis with multiple excitations were carried out and the applicability of the analyses was confirmed. Moreover, the seismic response of actual crossover piping was estimated and the feasibility was evaluated.

Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities: Part 4 — Failure Behavior of Crossover Piping for Seismic Isolation System

2014 ◽  
Author(s):  
Teruyoshi Otoyo ◽  
Akihito Otani ◽  
Shunsuke Fukushima ◽  
Masakazu Jimbo ◽  
Tomofumi Yamamoto ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Seismic Isolation ◽  
Evaluation Method ◽  
Low Cycle Fatigue ◽  
Response Analysis ◽  
Failure Behavior ◽  
Isolation System ◽  
Isolation Systems ◽  
Seismic Isolation Systems ◽  
Failure Location

This paper provides a part of the series titled “Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities”. This part shows the failure behavior of crossover piping installed in a seismic isolated plant. The considered crossover piping is supported on one side by an isolated building and by a non-isolated building on the other side. During an earthquake, the piping structure is deformed due to the large relative displacements between the two buildings and at the same time excited by the different building seismic responses. Therefore, the high-pressure crossover piping structure requires both flexibility and strength. In this study, 1/10 scaled shaking tests and FEM analyses have been performed to investigate the failure behavior of the crossover piping, where both seismic motions and excitations have been taken into account. It was confirmed that the failure occurs at the piping elbow through low cycle fatigue. Moreover, the results of the elastic-plastic response analysis, which simulates an extreme level of excitation corresponding to more than three times the design level, are in good agreement with the test results. The simulation also succeeded in predicting the experimental failure location.

scholarly journals Innovative Structural Solutions for Prefab Reinforced Concrete Hall-Type Buildings

2019 ◽  
Vol 13 (1) ◽  
pp. 149-163 ◽  
Author(s):  
Stefano Sorace ◽  
Gloria Terenzi
Keyword(s):  
Reinforced Concrete ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Seismic Protection ◽  
Isolation System ◽  
Fluid Viscous Dampers ◽  
Protection Strategies ◽  
Additional Costs ◽  
Design Earthquake ◽  
Bracing System

Background:The anti-seismic design of prefab reinforced concrete buildings is usually carried out with a conventional ductility-based approach. This implies a remarkable plastic demand on columns, as well as damages to the connections of structural and non-structural members, for seismic events with comparable intensity to the basic design earthquake normative level.Objective:In view of this, a study was developed and aimed at extending to the field of new prefab reinforced concrete structures the application of advanced seismic protection strategies, capable of guaranteeing undamaged response up to the maximum considered earthquake normative level.Method:A benchmark building was designed as demonstrative case study for this purpose, in the three following hypotheses: (a) according to a traditional ductility-based approach; (b) by incorporating dissipative bracings, equipped with fluid viscous dampers; (c) by placing a seismic isolation system at the base, composed of a set of double curved surface sliders.Results:The results of the verification analyses show that the targeted performance for the design solutions b) and c) is obtained with sizes of columns and plinths notably smaller than those for the conventional design. This allows compensating the additional cost related to the incorporation of the protective devices, for the dissipative bracing system, and limiting additional costs below 25%, for the base isolation solution. At the same time, a supplemental benefit of the latter is represented by greater protection of contents and plants, as they are fully supported by the seismically isolated ground floor.Conclusion:The study highlights the advantages offered by the two advanced seismic protection technologies in an unusual field of application, guaranteeing an enhanced performance of structural and non-structural elements, as well as reduced member sizes, as compared to the traditional ductility-based design.

Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities: Part 5 — Fatigue Test of the Crossover Piping

2014 ◽  
Author(s):  
Kotoyo Mizuno ◽  
Hiroshi Shimizu ◽  
Masakazu Jimbo ◽  
Naohiko Oritani ◽  
Shigenobu Onishi
Keyword(s):  
Fatigue Life ◽  
Fatigue Test ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Evaluation Method ◽  
Failure Modes ◽  
Structural Integrity ◽  
Relative Displacement ◽  
Isolation Systems ◽  
Seismic Isolation Systems

This paper provides a part of the series of “Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities”. It is assumed the main steam crossover piping is damaged by the ratcheting deformation based on the relative displacement and the inertia load by the earthquake between the buildings and the internal pressure. This part shows a low cycle ratcheting fatigue test using the scaling model under the combined loadings based on the relative displacement and the inertia load by the earthquake between the buildings and analyses were performed to confirm the failure modes and the fatigue life of the pipe elbow for the fatigue damage of the long-period ground motion. As a result, the fatigue life under combined loads was sufficiently higher than the design criteria and analyses are good match with the test results. So, it confirmed the structural integrity of the crossover piping.

Resonance Characteristics of Unidirectional Viscous and Coulomb-Damped Vibration Isolation Systems

1967 ◽  
Vol 89 (4) ◽  
pp. 729-740 ◽  
Author(s):  
Jerome E. Ruzicka
Keyword(s):  
Resonant Frequency ◽  
Vibration Isolation ◽  
Elementary Theory ◽  
Rate Of Change ◽  
Design Data ◽  
Isolation System ◽  
Extensive Evaluation ◽  
Wide Range ◽  
Isolation Systems ◽  
Damped Systems

Elementary vibration theory based on transfer response analyses of single-degree-of-freedom systems indicates that an increase in isolation system damping causes a decrease in resonant transmissibility. This theory further specifies that, for viscous-damped systems, an increase in damping decreases the resonant frequency whereas, for Coulomb-damped systems, an increase in damping increases the resonant frequency. It is frequently found in practice that an increase in damping may increase the resonant transmissibility and cause a change in resonant frequency opposite to that predicted by elementary theory. This paper presents a more extensive evaluation of the resonance characteristics of unidirectional vibration isolation systems, including the effects of directly coupled and elastically coupled damping elements. Mathematical models and absolute transmissibility characteristics of viscous and Coulomb-damped vibration isolation systems are discussed and resonance characteristics are analyzed in terms of the resonant frequency ratio, the resonant transmissibility, and the rate of change of these parameters with damping. Design data are presented graphically for parametric variations of stiffness and damping which are sufficiently broad to encompass a wide range of practical engineering problems.

The Influence of Isolator Hysteresis on Equipment Performance in Seismic Isolated Buildings

2010 ◽  
Vol 26 (1) ◽  
pp. 275-293 ◽  
Author(s):  
T. Y. Yang ◽  
Dimitrios Konstantinidis ◽  
James M. Kelly
Keyword(s):  
United States ◽  
Seismic Isolation ◽  
The United States ◽  
Large Displacements ◽  
Isolation System ◽  
Seismic Input ◽  
Alternative Approach ◽  
Moderate Earthquake ◽  
Time Histories ◽  
Isolation Systems

The seismic isolation code which must be used for all seismic isolated buildings in the United States is conservative in many of its provisions. While seismic isolation is flourishing in other countries, it is underused in the United States. For static analysis and for the selection of time histories, the spectrum is constant-velocity for periods of one second and longer, leading to large displacements for long period systems and forcing the designer to use added damping to reduce these displacements. The damping systems used are hysteretic with the characteristic that damping decreases with increasing displacement. To achieve the damping needed to reduce these large displacements, expected from very rare seismic input, means that at smaller displacements, caused by realistic levels of seismic input, the damping will be very much higher, and there may be stiffening of the isolation system, meaning that the building may not act as isolated and there may be an impact on sensitive internal equipment. This paper shows how highly damped isolation systems are counterproductive to isolation and suggests an alternative approach that will conform to code requirements but ensure that, at moderate earthquake inputs, the equipment remains protected, and the large code-mandated displacements are kept to acceptable levels.

Sign in / Sign up

Export Citation Format

Share Document