This document discusses base isolation and seismic considerations in civil engineering. It defines seismic forces as those generated by earthquakes. Different seismic zones in India are identified based on earthquake risks. The magnitude and intensity of earthquakes are defined, with magnitude measuring the energy released and intensity measuring local damage. Hazards from earthquakes like liquefaction, ground shaking, and landslides are described. Methods to prevent liquefaction include compaction, drainage and stone columns. Earthquake-resistant design aims to resist ground motions without collapse. Base isolation is introduced to reduce forces transmitted to structures by placing them on flexible pads. Seismic dampers also help absorb seismic energy.

1. A
Seminar
On
“Base Isolation and Seismic Consideration in Civil
Engineering”
APPLIED MECHANICS DEPARTMENT
S. V. NATIONAL INSTITUTE OF TECHNOLOGY
SURAT – 395 007
Prepared By: ANKIT JAIN (U10CE078)

2.  Seismic Forces is generated due to
Earthquake.
 Earthquake is a natural disaster.
 It is a violent shaking of earth.
 It happens due to mass shifting in
bedrock.
 Because it is a natural disaster so
we can’t control it. Only we can
try that the damage should be
minimum.
WHAT IS SEISMIC FORCE?
Bhuj Earthquake, 2001

3. Different Seismic Zones In India

4. MAGNITUDE AND INTENSITY
OF EARTHQUAKE
1. MAGNITUDE
The Magnitude (M) is a quantitative measure of its strength in
terms of energy released .
2. INTENSITY
The intensity of an earthquake is measured qualitatively in
terms of damages caused by it at a particular location.
In general, larger the earthquake, greater is the intensity.
Magnitude of an earthquake is a measure of its size. While
intensity is an indicator of the severity of shaking generated
at a given location.

5. HAZARDS DUE TO
EARTHQUAKE
a) Liquefaction of Soils
b) Ground Shaking
c) Surface Rupture
d) Landslides
e) Lateral Spreading
f) Shear Failure of Foundation
g) Settlements of Structures
h) Failure of Retaining Wall
i) Tsunamis And Seiches

6. LIQUEFACTION OF SOIL
 Liquefaction is a state of saturated cohesion less soil when its
shear strength is reduced to zero due to pore water pressure
caused by vibration during an earthquake. The soil starts
behaving like a liquid.
Soil Liquefaction During New Zealand Earthquake, 2011

7. PREVENTION OF LIQUEFACTION
a. Providing Deep Foundation
b. Compaction of Soil
c. Replacing the Liquefaction Soil
d. Grouting The Soil
e. Ground Water Pumping
f. Drainage of Soil
g. Providing Stone Columns

8. EARTHQUAKE-RESISTANT DESIGN
 Objective of Earthquake-Resistant Design is to make such
buildings that can resist effect of ground motion and would
not collapse during the strong Earthquake.
 All the components of the structure and foundations are
designed to resist inertia forces in addition to the normal
forces.
 All the walls must be jointed properly, so that they can act
together against the earthquake shaking at the time of seismic
force transferring to the ground.

9. BASE ISOLATION METHOD
 The idea behind the Base Isolation is to detach (isolate) the
building from the ground in such a way that earthquake
motions are not transmitted up through the building, or at least
greatly reduced.
 If a building is rested on flexible pads that offer resistance
against lateral movements, then some effect of the ground
shaking will be transferred to the building above. If the
flexible pads are properly chosen, the forces induced by
ground shaking can be a few times smaller than that
experienced by the building built directly on ground.

10. EFFECT OF BASE ISOLATION
METHOD

11. View of Basement in Bhuj Hospital Building
BASE ISOLATION METHOD

12. SEISMIC DAMPERS
 Seismic Dampers are fixed in place of structural elements as
diagonal braces.
 They absorb a part of seismic energy when it is transmitted
through them.
TYPES OF SEISMIC DAMPERS:
a. Viscous Dampers
Energy is absorbed by silicone-based
fluid passing between piston-cylinder
arrangement.

13. Viscous Damper
SEISMIC DAMPERS

14. SEISMIC DAMPERS
b. Friction Dampers
Energy is absorbed by surfaces with
friction between them rubbing against
each other
c. Yielding Dampers
Energy is absorbed by metallic
components.

15. Friction And Yielding Dampers
SEISMIC DAMPERS