ppt

2. Structure of Earth
2
• Earth - three layers - Crust, Mantle, Core.
• Crust - surface of Earth, Mantle - second inner part of
the Earth, Core - most inner part of the Earth.
T
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3. What are Earthquakes?
3
• sudden movement - surface of the earth - may be tiny
or several feet.
• enormous amounts - of energy released - greater -
Nuclear Bomb.
• sudden shift of rock - fracture of Earth.

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5. Origin of Earthquakes
5
• Earthquakes - Plate Tectonic Forces.
• Theory of Plate tectonic forces -Alffl1redl Wq
• He stated that continents moved from their
original position - Continental Drift.

6. • Different boundaries - tectonic forces induces Earth:
Divergent bounda ry, Convergent, Transform boundaries.
P t a t o s o rlhe &..tlh o sp he rc
'-----''-:;;:::::::::::::----' '
6
-:::=
::::::::--'- -
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Convocl1ve
C u r r e n t s
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7. Seismology
7
• When earthquakes occur, waves travel in Earth in
form of vibrations, such waves are called Seismic
Waves.
• Study of such waves - Seismology.
• Instrument measuring seismic waves - Seismometer.
• Graphs given by that seismometer - Seismic Graph.

8. Heavy Mass (resists motion)
Paper
(moves in
direction o1
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9. Termsof EQ's:
9
• sei s mic Load i1
1t,g : Main cause of Earthquakes
• S eismic PerformC111t,ce : Structure's ability -
functions - safety and serviceability - exposure -
earthquake.
• se£s m£c A 1
1t,aly s £s :Major intellectual tool -
understand seismic performance of structures.

10. • Earthquakes affect RCC
roquirod on both locos of n1embcrs. 1
structures too...
• Slabs forces the
beam to bend with it
when horizon tal
forces act.
(b)
Amount OJ
tont/On
(d) '- -
Figuro 4 : Earthquak e s hak i ng rev erses te n s io n
a n d comprosslo n I
n m e m bers - re1
1
1forcemgnt tS

11. Earthquake resistant designs
11
• Design - but it is analysis of forces - buildings due to
loads acting on it.
• If a building is enough to resist the earthquake, then
such building is called Earthquake resistant structure.
• Such design is called Earthquake resistant designs

12. Popular Earthquake resistant
Techniques
12
• Earthq uake may not be able to damage entire building
but it da1nages members of it.
• So special techniq ues are adopted:
Base Isolation Devices and
Seisn1ic Dampers.

13. Introduction of Resistant techniques
13
• Thought - Base Isolation Devices - separate building
from ground by some rubber devices.
• Seismic dampers - special devices - introduced in
buildi ng - absorb the energy - prod uced by seismic
waves.

14. Base Isolation Devices
14

15. Base Isolation Devices
Base isolation Devices - Active Control System which
contains:
• Sensors - measure external
excitation - structural response.
• Computer hardware and
software - compute control forces -
observed excitation.
• Actuators - provide -
necessary control forces.
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16. • Control Force Devices
• Active Tuned Mass Dampers - natural extension -
experiments indicate 25% less damage.
• Tendon Control - used even for active devices - works
when active devices are off - act by resisting tension
in structure.
16

17. Rrinc1
ple Diagram of Anti E
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ubber 8earinQ

18. B
ase
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D u U d l n g I s o l a t o r d u r l n p £ • n h q u 11
1fo
/Julldlnt:1 on f l o x l b l o p.1tdt1 c o n n o c r o d to b u l l d l n C t 1
• n d f o u n d 1 1 t 1 o n bulld1nQ "
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Grolll'ld F f g u l'O 1: B u l l d l ng o n f le x lb le s u p p o r t s s ha"'-f t •
loaaor - this technique i:s c slled B a s a lsolifiton

21. Attachment Plates Stif fening Plates
Rubber Layers
Lead Plug

22. ....---
2
2
Seismic Dampers

23. 2
3
SD's in structures:
· -
- ..
= =
--
-
..
.
..
-
.

24. 2
4

25. • Dampers are of:
Viscous Damper
eac/1device Is sullal>le for a certain Ouildin{J.
);:>- Friction Damper
);>- Yielding Damper
.-
-otme!al ........_
/ Oii
(c) Yield ing Dampers
F igure 3: Seis m ic Energy D is s ipation Devices -
(b) Fr iction Damper

26. Ccn1ent10ffl!a tr eartr:qJak£
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27. lwizooh
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fixedtu
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28. Note points:
28
BID
• separating structures from
ground by means of devices.
• Can be done when structure
is already constructed, but it
is costly.
• Cheaper compared to
Seismic Dampers.
SD'S
• additional systems
introduced in structures.
• even when structure is
completed, systems can be
introduced.
• Very costly, since linked with
hardware programmes.

29. 29

30. 30