Base Isolation: Linear Theory and Design

1990 ◽  
Vol 6 (2) ◽  
pp. 223-244 ◽  
Author(s):  
James M. Kelly
Keyword(s):  
Linear Theory ◽  
Seismic Isolation ◽  
Large Scale ◽  
Base Isolation ◽  
Ground Movement ◽  
Engineering Profession ◽  
Shake Table Testing ◽  
Static Testing ◽  
Degree Of Acceptance ◽  
Isolation Systems

The idea that a building can be uncoupled from the damaging effects of the ground movement produced by a strong earthquake has appealed to inventors and engineers for more than a century. Many ingenious devices have been proposed to achieve this result, but very few have been implemented and the concept now referred to as base isolation or seismic isolation has yet to be generally accepted by the engineering profession. Although most of the proposed systems are unacceptably complicated, in recent years a few practical systems have been developed and implemented. While some of these systems have been tested on large-scale shaking tables, none have to date been tested as-built by a strong earth tremor. The shake table testing and related static testing of full-scale components such as isolation bearings, however, has led to a certain degree of acceptance by the profession and it is possible that the number of practical implementations of base isolation will increase quite dramatically in the next few years. This paper describes recent implementations of base isolation and describes an approximate linear theory of isolation which can be used for the design of base isolation systems that use multilayer elastomeric isolators.

Effects of Damper Force Ranges and Ground Motion Pulse Periods on the Performance of Semi-Active Isolation Systems

2003 ◽  
Author(s):  
Henri Gavin ◽  
Julie Thurston ◽  
Chicahiro Minowa ◽  
Hideo Fujitani
Keyword(s):  
Ground Motion ◽  
Large Scale ◽  
Base Isolation ◽  
Near Field ◽  
Shaking Table ◽  
Isolation System ◽  
Active Isolation ◽  
Isolation Systems ◽  
Fail Safe ◽  
Strong Ground

A large-scale base-isolated steel structural frame was tested at the shaking table laboratory of the National Research Institute for Earth Sciences and Disaster Prevention. These collaborative experiments featured auto-adaptive media and devices to enhance the performance of passive base isolation systems. The planning of these experiments involved determining appropriate device control methods, the development of a controllable damping device with fail-safe characteristics, and the evaluation of the performance of the controlled isolation system subjected to strong ground motion with pronounced near-field effects. The results of the planning study and their large-scale experimental confirmation provide guidelines for the development and implementation of auto-adaptive damping devices for full scale structures.

Response Analysis of a Seismic Isolated Structure Considering a Probabilistic Approach

2014 ◽  
Author(s):  
Naoki Akamatsu ◽  
Satoshi Fujita ◽  
Keisuke Minagawa
Keyword(s):  
Sensitivity Analysis ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Large Scale ◽  
Probabilistic Approach ◽  
Nonlinear Behavior ◽  
Response Analysis ◽  
Isolation Systems

Japan is one of the most advanced countries in earthquake technology. Isolation systems are widely used in large-scale structures such as hospitals and communication centers. For example, an isolated office building has been used as a hub of recovery from accident by Great East Japan Earthquake in Fukushima nuclear power plant. In the meantime, application of probabilistic risk assessment is used for structure of nuclear power plants. In 2006, Regulatory Guide for Reviewing Seismic Design was revised and according to guideline, it is necessary to consider the residual risk1. In addition, seismic isolation systems are expected to be used for nuclear power plants. Recently, the risk of isolation system’s failure needs to be assessed in case of large ground motion. This paper deals with probabilistic approach on seismic response of an isolated structure. Consequently, sensitivity analysis is carried out. Then, as nonlinear behavior in rubber bearings occurs during huge earthquake, it has to be considered in the sensitivity analysis.

Comparative Studies of Base Isolation Systems Featured with Lead Rubber Bearings and Friction Pendulum Bearings

2016 ◽  
Vol 846 ◽  
pp. 114-119
Author(s):  
Arati Pokhrel ◽  
Jian Chun Li ◽  
Yan Cheng Li ◽  
Nicos Maksis ◽  
Yang Yu
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Time History ◽  
Elastic Base ◽  
Base Shear ◽  
Isolation Technique ◽  
Rubber Bearing ◽  
Lead Rubber Bearing ◽  
Isolation Systems ◽  
Friction Pendulum

Due to the fact that safety is the major concern for civil structures in a seismic active zone, it has always been a challenge for structural engineers to protect structures from earthquake. During past several decades base isolation technique has become more and more popular in the field of seismic protection which can be adopted for new structures as well as the retrofit of existing structures. The objective of this study is to evaluate the behaviours of the building with different seismic isolation systems in terms of roof acceleration, elastic base shear and inter-storey drift under four benchmark earthquakes, namely, El Centro, Northridge, Hachinohe and Kobe earthquakes. Firstly, the design of base isolation systems, i.e. lead rubber bearing (LRB) and friction pendulum bearing (FPB) for five storey RC building was introduced in detail. The non-linear time history analysis was performed in order to determine the structural responses whereas Bouc-Wen Model of hysteresis was adopted for modelling the bilinear behaviour of the bearings. Both isolation systems increase the fundamental period of structures and reduces the spectral acceleration, and hence reduces the lateral force cause by earthquake in the structures, resulting in significant improvement in building performance; however the Lead Rubber Bearing provided the best reduction in elastic base shear and inter-storey drift (at first floor) for most of the benchmark earthquakes. For the adopted bearing characteristics, FPB provided the low isolator displacement.

Energy Harvesting From Building Seismic Isolation With Multi-Mode Resonant Shunt Circuits

2014 ◽  
Author(s):  
Mincan Cao ◽  
Lei Zuo
Keyword(s):  
Energy Harvesting ◽  
Vibration Control ◽  
Seismic Isolation ◽  
Large Scale ◽  
Base Isolation ◽  
Numerical Study ◽  
Vibration Reduction ◽  
Host Structure ◽  
Multi Mode ◽  
Shunt Circuit

A novel electromagnetic transducer shunt circuit is proposed in this paper for dual-functional energy harvesting and vibration control of building seismic isolation. In recent decades, base isolation systems are widely used in low and middle rise buildings. Even though base isolation can filter out high frequency excitation from earthquake, it still necessary to consider higher order modes’ vibration in host structure. The new design extends the multi-mode shunt circuit technology in piezoelectric area in order to achieve good vibration suppression into the seismic isolation of multi degree of freedoms (MDOF) of host structure of buildings, and use multi-mode circuit to achieve both energy harvesting and seismic vibration control. A numerical study of simplified two degree of freedom base isolation is presented in this paper. This passive system is also examined by giving recorded earthquake excitation. The stimulation results show that this new design could take advantage both of low-pass filtering capacity of base isolation system and resonant vibration reduction of electromagnetic shunt circuit. It is also observed that parameters selected for vibration reduction of building can effectively achieve large-scale energy harvesting at same time.

Comparison of Earthquake Simulator Test Results with the SEAONC Tentative Seismic Isolation Design Requirements

1990 ◽  
Vol 6 (2) ◽  
pp. 403-417 ◽  
Author(s):  
Michael C. Griffith ◽  
Ian D. Aiken ◽  
James M. Kelly
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Low Frequency ◽  
Frame Structure ◽  
Wall Structure ◽  
Elastomeric Bearings ◽  
Earthquake Simulator ◽  
Isolation Systems ◽  
Structural Engineers ◽  
Steel Frame Structure

Earthquake simulator tests were performed on a 1/5-scale, 6-story reinforced concrete shear-wall structure and a 1/4-scale, 9-story braced steel frame structure. The structures were supported by five different base isolation systems which consisted of various types and combinations of elastomeric bearings. The main objective of this study was to compare the peak experimental displacements of the base isolation systems tested with values given by the tentative base isolation design provisions proposed by the Seismology Committee of the Structural Engineers Association of Northern California (SEAONC). Comparisons of experimental results and values from the SEAONC base isolation design formula for displacements indicated that the formula is generally conservative, even for predominantly low frequency earthquake motions, provided the ground motion coefficient Av (based on the effective peak velocity as defined by ATC 3-06) is used in the design equation for base-isolated structures with periods greater than 1 second.

scholarly journals Earthquake-Resilient Design of Seismically Isolated Buildings: A Review of Technology

Vibration ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 602-647
Author(s):  
Cem Yenidogan
Keyword(s):  
High Performance ◽  
Seismic Isolation ◽  
Large Scale ◽  
Performance Enhancement ◽  
Response Prediction ◽  
Wide Range ◽  
Reliable Performance ◽  
New Construction ◽  
Isolation Systems ◽  
Earthquake Resilience

Earthquake Seismic isolation plays an important role in achieving sustainable earthquake resilience communities. Seismic isolation method is a justified, mature, and reliable performance enhancement strategy for a wide range of structural systems and valuable contents. As a result of the targeted response modification, high-performance expectations and earthquake resilience can be achieved during the service life of the structures that are compliant with the design code requirements. Design and analysis procedures of isolation systems in standards were evolved substantially to expand the use of isolation technology and quantify the benefits of isolation systems to overcome the existing impediments. Strictly speaking, new tools are offered to the engineering community to highlight the possible issues that may appear in isolation units beyond the design basis earthquake level to improve the accuracy of response prediction. This paper aims to overview the characteristics of frequently used isolation systems in the industry with mathematical models, design criteria toward sustainable communities, the current state of practice along with the set forth design requirements of selectively well-known standards with special emphasis to the ELF procedure from the perspective of performance-based design philosophy. Additionally, two large-scale seismic isolation applications in the world are given as benchmark studies for the new construction and upgrading scheme in the content of the study.

New Seismic Isolation Systems for Floating Houses

2012 ◽  
Author(s):  
C. S. Tsai ◽  
H. C. Su ◽  
W. C. Liao ◽  
Yan-Ming Wang
Keyword(s):  
Climate Change ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Isolation System ◽  
Sea Levels ◽  
Earthquake Resistant ◽  
Earthquake Resistant Structures ◽  
Base Isolation System ◽  
Isolation Systems ◽  
Seismic Isolation Systems

Inhabitable land has been decreasing due to the continual rise in sea levels caused by global warming. In response to this climate change, we need to consider looking for living spaces on water surfaces as well as building earthquake-resistant structures, particularly in flood and earthquake prone areas. This paper presents an experimental study on a new base isolation system in mitigating the response of a floating house that is located in a port. Experimental results show that the seismic response of the floating house was considerably reduced by the proposed isolation system with a proper displacement limit.

scholarly journals Base isolation design and analysis for the 7-story apartment building “Stepanakert-sections-4-5” with R/C monolithic load-bearing walls and asymmetric plan

2020 ◽  
Vol 5 (2) ◽  
pp. 047-056
Author(s):  
Mikayel G. Melkumyan
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Apartment Building ◽  
Isolation System ◽  
Load Bearing ◽  
Seismic Code ◽  
Fitness Clubs ◽  
Manufacturing Testing ◽  
Isolation Systems ◽  
The Cost

In recent years seismic isolation technologies in Armenia were extensively applied in construction of multi-story residential, medical, hotel, airport, and business center complexes with parking floors and with floors envisaged for offices, shopping centers, fitness clubs, etc. To date there are 55 seismic isolated buildings in the country newly constructed or retrofitted by base or roof isolation systems. Of this number of buildings 48 were erected thanks to the works of the author of this paper and in nowadays Armenia is well known as a country where seismic (base and roof) isolation systems are widely implemented in civil construction. The number of seismically isolated buildings per capita in Armenia is one of the highest in the world – second after Japan. The paper given below emphasizes achievements also in local manufacturing/testing of seismic isolation laminated rubber-steel bearings (SILRSBs). Several remarkable projects on construction of base isolated buildings are briefly mentioned in the paper to demonstrate the experience accumulated in Armenia. Based on the gained experience further developments take place and unique base isolation structural concepts and technologies created by the author are applied more and more in construction of new buildings. In this paper base isolation design and analysis by the Armenian Seismic Code for the 7-story apartment building to be constructed in Stepanakert is described. This will be a first application of base isolation technology to a building the bearing system of which consists of reinforced concrete (R/C) monolithic load-bearing walls and building has an asymmetric plan. It is stated that suggested seismic isolation strategy will reduce the cost of construction of the given building on about 35% in comparison with the cost of conventional construction. Obtained results indicate the high effectiveness of the proposed structural concept of isolation system and the need for further improvement of Seismic Code provisions regarding the values of the reduction factors.

Shake table testing on restoring capability of double concave friction pendulum seismic isolation systems

2017 ◽  
Vol 46 (14) ◽  
pp. 2337-2353 ◽  
Author(s):  
Felice Carlo Ponzo ◽  
Antonio Di Cesare ◽  
Gianmarco Leccese ◽  
Domenico Nigro
Keyword(s):  
Seismic Isolation ◽  
Shake Table ◽  
Shake Table Testing ◽  
Isolation Systems ◽  
Seismic Isolation Systems ◽  
Friction Pendulum
Sign in / Sign up

Export Citation Format

Share Document