This document discusses techniques for making structures earthquake resistant. It explains that earthquakes occur due to tectonic plate movement and stresses in the earth's crust. To resist earthquakes, structures can use shear walls, bracing, dampers, or isolation. Dampers absorb energy from shaking by deforming inelastically (metallic dampers), creating friction through sliding plates (friction dampers), or forcing fluid through holes (viscous dampers). Proper quality control of materials and construction is also important for earthquake resistance.

1. EARTHQUAKE RESISTANT
STRUCTURES
PRESENTED BY
M.K.MOHAMED ASHIQ ALI

2. AGENDA
 What is Earthquake?
 How earthquake occurs?
 Causes and effects of Earthquakes
 Quality control
 Techniques for resist Earthquakes
 Shear walls
 Advantages of Shear walls
 Dampers
 Conclusion


3. What is earthquake?
 They are natural disasters of a
generally un predictable nature
 It is the shaking of earth due to
the movement of earth’s crust
 A sudden, rapid shaking of
earth caused by the breaking
and shifting of rocks beneath
the earth surface

4. How Earthquakes occurs?
 Earthquakes occur when two tectonic
plates move suddenly against each
other.
 Because of earth’s rotation and other
energy factors different shells or the
rock layers constantly move or slid
past each other.
 Different continental mass fragments
of lesser densities float and move
overriding the denser rock layers.

5. Causes and Effect of Earthquakes
 Earthquakes are casually related to
compression or tensional stresses.
 Volcanic eruptions, rock fall,
landslides and explosions can also
cause a quake
 Land slides
 Liquefaction
 Tsunamis

6. Quality control
 Special care is needed in construction to ensure that the elements
meant to be ductile are indeed provided with features that give
adequate ductility.
 Thus, strict adherence to prescribed standards of construction
materials and construction processes is essential in assuring an
earthquake resistant building.

7. Elements of Good quality control
 Regular testing of construction materials at qualified
laboratories(at site or away)
 Periodic training of workmen at professional training houses, and
 on site evaluation of the technical work

8. Techniques for Resist Earthquakes
 Shear walls
 Bracing
 Dampers
 Isolation
 Rollers

12. 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. Here are some of them:

13. Metallic damper
 Metallic dampers are usually made from steel.
 They are designed to deform so much when the building vibrates
during an earthquake that they cannot return to their original shape.
 This permanent deformation is called inelastic deformation, and it
uses some of the earthquake energy which goes into building.
X - Plate Metallic Damper

14. Friction Damper
 Friction dampers are designed to have moving parts that will slide
over each other during a strong earthquake.
 When the parts slide over each other, they create friction which
uses some of the energy from the earthquake that goes into the
building.

15.  The damper is made up from a set of steel plates, with slotted
holes in them, and they are bolted together. At high enough
forces, the plates can slide over each other creating friction.
 The plates are specially treated to increase the friction between
them.

16. Viscous Damper
 Viscous fluid dampers are similar to shock absorbers in a car.
They consist of a closed cylinder containing a viscous fluid like oil.
 A piston rod is connected to a piston head with small holes in it.
The piston can move in and out of the cylinder. As it does this, the
oil is forced to flow through holes in the piston head causing
friction.

17. Suggestions
 Avoid weak column and strong beam design
 Provide thick slab which will help as a rigid diaphragm
 Provide cross walls which will stiffen the structures
 Provide shear walls in a symmetrical fashion
 Increase in the transverse (Shear) reinforcement.
 Horizontal lintel band should be provided
 Revision/ updation of building code of Pakistan
 The building must be regular and symmetrical in shape
 Reinforcing bars should be provided at the corners and the junctions of
the walls