1 Base Isolation Base Isolation Base isolation is a technique of controlling Base isolation is a technique of controlling structural response in which the building or structural response in which the building or structure is decoupled from the horizontal structure is decoupled from the horizontal components of the earthquake ground motion by components of the earthquake ground motion by interposing a layer with low horizontal stiffness interposing a layer with low horizontal stiffness between the structure and the foundation. between the structure and the foundation. This layer gives the structure a fundamental This layer gives the structure a fundamental frequency that is much lower than its fixed frequency that is much lower than its fixed - - base base frequency and also much lower than the predominant frequency and also much lower than the predominant frequencies of the ground motion frequencies of the ground motion . . The isolation system does not absorb the earthquake The isolation system does not absorb the earthquake energy, but rather deflects it through the dynamics energy, but rather deflects it through the dynamics of the system of the system . .
1 Base Isolation Base isolation is a technique of controlling structural response in which the building or structure is decoupled from the horizontal components.
Dec 17, 2015
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Base IsolationBase Isolation
Base isolation is a technique of controlling structural Base isolation is a technique of controlling structural response in which the building or structure is decoupled response in which the building or structure is decoupled from the horizontal components of the earthquake ground from the horizontal components of the earthquake ground motion by interposing a layer with low horizontal stiffness motion by interposing a layer with low horizontal stiffness between the structure and the foundation.between the structure and the foundation.
This layer gives the structure a fundamental frequency that This layer gives the structure a fundamental frequency that is much lower than its fixedis much lower than its fixed--base frequency and also much base frequency and also much lower than the predominant frequencies of the ground lower than the predominant frequencies of the ground motionmotion. .
The isolation system does not absorb the earthquake The isolation system does not absorb the earthquake energy, but rather deflects it through the dynamics of the energy, but rather deflects it through the dynamics of the systemsystem. .
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Displacement and Acceleration Spectra
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Concept of Seismic Isolation
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Without base isolation With base isolation
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Seismic Isolators
Rubber
Steel plates
1. Laminated Rubber Bearings
The bearing is very stiff and strong in the vertical direction, but flexible in the horizontal direction
xb
yb
kbcb
cb
kb
gx
gy
Mathematical model
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2. Lead Rubber Bearings
yb
cb
xb
kb
cb
kb
gx
gy
The lead plug reduces, or dissipates, the energy of motion - i.e., kinetic energy, by converting that energy into heat.
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Lead Rubber Bearing at Building Site
99
1010
3. Friction Pendulum Bearings
1111
Slider
1. The building is supported by bearing pads that have a curved surface and low friction.
2. During an earthquake, the building is free to slide on the bearings.
Friction Pendulum Bearings
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BHUJ HOSPITAL PROJECT
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Bhuj District Hospital, IndiaBhuj District Hospital, India - completed January 2003 - completed January 2003
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Lead Rubber Bearing beingLead Rubber Bearing beingLowered into Position Lowered into Position
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Lead Rubber Bearing on Site,Lead Rubber Bearing on Site,Bhuj District Hospital, India 2002Bhuj District Hospital, India 2002
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Lead Rubber Bearings,Lead Rubber Bearings, Bhuj District Hospital, India 2002 Bhuj District Hospital, India 2002
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PARLIAMENT NEW ZEALAND
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