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What Is Earthquake?
An earthquake is a vibration that travels through the earth's crust.
A large truck rumbling down the street
Volcanic eruption
Meteor impacts
Underground explosions
Collapsing structures
Movements of the earth’s plates
Earthquake Resistant Buildings
Earthquakes can cause buildings to vibrate
Every building has a number of ways, or modes, in
which it can vibrate naturally. In each mode, the
building vibrates to and fro with a particular
distorted shape called its mode shape.
Earthquakes usually make buildings vibrate most
strongly in their fundamental mode, the mode of
vibration with the lowest frequency
Strengthening Buildings for Earthquakes
Earthquakes cause sideways forces on buildings
These are some of the structural systems used to resist sideways forces
Adding Dampers
Dampers can be installed in the structural frame of a building to absorb some of the energy going into the building from the shaking ground during an earthquake.
The dampers reduce the energy available for shaking the building. This means that the building deforms less, so the chance of damage is reduced.
There are many types of dampers that can be installed in buildings.
Major Earthquake Resisting Structures
Bhuj Hospital.
Taipei 101.
Coronado Bay Bridge.
San Francisco City hall.
Yokohama Landmark tower.
International Airport of Istanbul.
Nargona Palace.
2001 Bhuj Earthquake: Preliminary Report from IITKanpur
A Powerful Earthquake of magnitude 6.9 on Richter-Scale rocked the Western Indian State of Gujarat on the 26th of January, 2001.
This earthquake was so devastating in its scale and suffering that the likes of it had not been experienced in past 50 years.
The epicenter of the quake was located at 23.6 north Latitude and 69.8 east Longitude, about 20 km Northeast of Bhuj Town of the Kutch district in Western Gujarat.
Effects
At a depth of only 23 kms below surface this quake generated intense shaking which was felt in 70% region of India and far beyond in neighbouring Pakistan and Nepal too.
Twenty-one of the total 25 districts of the state was affected in this quake.
Around 18 towns, 182 talukas and 7904 villages in the affected districts have seen large-scale devastation. The affected areas even spread up to 300 km from the epicentre.
Earthquake resisting Technology used in Bhuj Hospital
Aseismic Design Philosophy
Decouple the Superstructure from Ground with or without Flexible Mounting
Period of the total system is elongated
A Damper Energy Dissipating Device provided at the Base Mountings.
Rigid under Wind or Minor Earthquake.
Accordingly, by using base isolation devices in the foundations, the structure is essentially uncoupled from the ground motion during earthquakes