Earthquake resistance Structures

1. NATIONAL INSTITUTE OF
TECHNICAL TEACHERS’
TRAINING AND RESEARCH
NAME : ARYYAKA SARKAR
COURSE NAME : STRUCTURAL ENGINEERING
SEMESTER - 1st
ROLL NUMBER - 16011723001
REG. NO. - 231600410009
SEMINAR - I , SE -181

2. CONTENTS
 What is Earthquake?
 Types of Earthquake?
 How Earthquake Occurs?
 Causes and Effects of Earthquake
 Seismic Waves
 Seismic Performance and Design
 Improving Earthquake Resistant of the Minor Building
 Shear Walls
 Advantages of Shear Walls
 Earthquake Resisting Structure Techniques
 Base Location Method
 Energy Dissipation Device (Seismic Dampers)
 Keeping Building Up thrust
 Conclusion

3. What is Earthquake
 An earthquake is the sudden release of strain energy in the
Earth's crust, resulting in waves of shaking that radiate
outwards from the earthquake source.
 Earthquake can happen due to movement of the Earth’s
tectonic plates or due other natural incidents like volcanic
eruptions or landslides etc. Earthquake also can happen due to
human actions like mine blasts, nuclear test etc.

4. Types of Earthquake
There are two types of Earthquake:
I. Inter Plate Earthquake
II. Intra-plate Earthquake
In both types of Earthquake, during earthquake at fault strike
slip (horizontal movement) and dip slip (vertical movement)
happens.

5. How Earthquake Occurs?
 Because of Earth’s rotation and other energy factors tectonic
plates constantly move or slide past each other. Different
continental mass fragments of lesser densities float and move
overriding the denser rock layers.
This is the prime reason for Earthquake to happen naturally.

6. Causes of Earthquake
 Earthquake are caused due to release of compression or
tensile stress generated due to movement of tectonic
plates.
 Volcanic eruptions, rock fall, landslides and explosions
can also cause an earthquake.

7. Fault
 A fault is nothing but a crack or weak
zone inside the Earth. When two plates
rub against each other along a fault,
they don’t slide smoothly. Tectonic
forces continue to prevail at the
boundary between two plates. The
plate margins exhibit deformation as
seen in terms of bending, compression,
tension and friction.
 The rocks eventually break giving rise to
an earthquake, because of building of
stresses beyond the limiting elastic
strength of the rock.

8. Seismic Waves
They are of two types:-
• Body Waves-
a.) P-waves
b.) S-waves
• Surface Waves (Slowest and Damaging)

9. Effects Of Earthquake
 Ground Motion
 Landslides
 Ground Displacement
 Liquefaction
 Tsunamis
 Aftershocks

10. Earthquake Do not Kill People
Improperly Designed Structures
Do!!!

11. Seismic Performance
• Ability of Structure to sustain its function i.e safety and
serviceability during and after earthquake.
Seismic Design
• To Design structures subjected to earthquake exposure.

12. Improving Earthquake Resistance of Minor
Building
 The building must have a simple plan.
 The foundation should be made on a hard and uniform ground.
 The frame of the building should have adequate ductility in
addition to required strength.

13. Configuration Of Building

14. 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 process is essential in assuring an
earthquake resistant building.

15. Shear Wall
 Vertically oriented wide beams.
 It carries seismic loads down to the bottom of foundation.
 Provides large strength and stiffness to buildings.
 Thickness generally varies from 150mm to 400mm in high ise buildings.
 Effective when located along the exterior perimeter of building.

16. Advantages of Shear Walls
 Efficient in terms of-
I. Cost
II. Effectiveness
III. Construction
 Helps in minimizing the effect on non-structural elements.
E.g. Glass, Windows etc.

17. Earth Quake Resisting Structures Techniques
 Base Isolation Method
 Energy Dissipation Device
 Keeping Building Up Thurst

18. Base Isolation
 Introduces flexibility to the structures.
 Building is rested on flexible pads (Base Isolators).
 When earthquake strikes, the building does not moves.
 It is suitable for hard soil only.
 In India Base Isolation technique was first demonstrated after 1993
Killari Earthquake.
The four storey bhuj hospital building was built with base isolation
technique after 2001 Bhuj earthquake.

19. Energy Dissipation Device
 These are used in place of structural elements such as diagonal
braces.
 Acts like hydraulic shock absorbers in cars.
 When seismic energy is transmitted through them, dampers
absorb part of it, and thus damp the motion of the building.

20. Types of Seismic Damper
 Viscous Damper
 Friction Damper
 Yielding Damper
 Visco-elastic Damper

21. Keeping Building Up-Right
 Recently discovered in
Japan.
 It has found to be survived
even in extreme earthquakes.
 When the earthquake strikes
the system dissipates energy
in the building cores and
exteriors.
 The frames are free to rock
up and down within fittings
fixed at their bases.

22. Reference
• IS 1893 (Part I): 2016, CRITERIA FOR EARTHQUAKE
RESISTANT DESIGN OF STRUCTURES
• IS 4326:2013, EARTHQUAKE RESISTANT DESIGN AND
CONSTRUCTION OF BUILDINGS
• IS 13827:1993, IMPROVING EARTHQUAKE
RESISTANCE OF EARTHEN BUILDINGS
• IS 13828:1993, IMPROVING EARTHQUAKE
RESISTANCE OF LOW STRENGTH MASONRY
BUILDINGS
• IS 13920:2016, DUCTILE DETAILING OF REINFORCED
CONCRETE STRUCTURES SUBJECTED TO SEISMIC
FORCES

23. Conclusion
While Earthquake are Inevitable, Each earthquake need not
Convert into Disaster, as what comes in between is the Culture
of Safety and Prevention in Design and Construction.
Let us work together to build a Culture of Earthquake
Prevention.