Base Isolated Buildings
BASE ISOLATED BUILDINGS
What is base isolation?
When a building is built away (isolated) from the ground, resting on flexible bearings or pads known as base isolators.
It is of the most popular means of protecting a structure against earthquake forces. HISTORY
The first evidence of architects using the principle of base isolation for earthquake protection was discovered in Pasargadae.
One of the world's first base-isolated structures – the William Clayton building
Base Isolation System
Major types of base isolator systems
High damping rubber bearings
Elastomeric based Isolator systems
Lead rubber bearings
Elastomeric based Isolator systems
Elastomeric bearings have multiple layers of steel shim and rubber laminated together under high pressure and heat in a mold.
High damping rubber bearings
As an alternative to Elastomeric bearings, HDRB’s provide critical damping from 10% to 20% at 100% shear strains.
Lead rubber bearings
LRB are Elastomeric bearings that contain one or more lead plugs inserted into performed holes.
Lead
Lead is chosen because of its plastic property – it may deform with the movement of the earthquake, it will revert to its original shape, and is capable of deforming many times without losing strength.
Rubber
The rubber provides flexibility through its ability to move but return to its original position.
Steel
Using layers of steel with the rubber means the bearing can move in a horizontal direction but is stiff in a vertical direction
Damping Mechanism
1.Heavy damping mechanism incorporated in base isolation devices, is often considered a valuable source of suppressing vibrations thus enhancing building's Seismic performance.
2.Many buildings and bridges, both in New Zealand and elsewhere, are protected with lead dampers and lead and rubber bearings.
CASE STUDY
Wellington Hospital
The new Wellington Hospital was completed in
What is base isolation?
When a building is built away (isolated) from the ground, resting on flexible bearings or pads known as base isolators.
It is of the most popular means of protecting a structure against earthquake forces. HISTORY
The first evidence of architects using the principle of base isolation for earthquake protection was discovered in Pasargadae.
One of the world's first base-isolated structures – the William Clayton building
Base Isolation System
Major types of base isolator systems
High damping rubber bearings
Elastomeric based Isolator systems
Lead rubber bearings
Elastomeric based Isolator systems
Elastomeric bearings have multiple layers of steel shim and rubber laminated together under high pressure and heat in a mold.
High damping rubber bearings
As an alternative to Elastomeric bearings, HDRB’s provide critical damping from 10% to 20% at 100% shear strains.
Lead rubber bearings
LRB are Elastomeric bearings that contain one or more lead plugs inserted into performed holes.
Lead
Lead is chosen because of its plastic property – it may deform with the movement of the earthquake, it will revert to its original shape, and is capable of deforming many times without losing strength.
Rubber
The rubber provides flexibility through its ability to move but return to its original position.
Steel
Using layers of steel with the rubber means the bearing can move in a horizontal direction but is stiff in a vertical direction
Damping Mechanism
1.Heavy damping mechanism incorporated in base isolation devices, is often considered a valuable source of suppressing vibrations thus enhancing building's Seismic performance.
2.Many buildings and bridges, both in New Zealand and elsewhere, are protected with lead dampers and lead and rubber bearings.
CASE STUDY
Wellington Hospital
The new Wellington Hospital was completed in