EQ related presentation for seminar.pptx

1. B.KANDAVEL
M.E-STRUCTURAL
IRTT
GUIDELINES FOR PLANNING AND DESIGN
FOR EARTHQUAKE RESISTANT BUILDINGS

2. What is an earthquake?
 An earthquake is the vibration of Earth
produced by the rapid release of accumulated
energy in elastically strained rocks.
 Energy released radiates in all directions
from its source, the focus.
 Energy propagates in the form of seismic
waves.
 Sensitive instruments around the world
record the event.

3. What causes an earthquake?
Movement of Tectonic Plates
• Earth is divided into sections called
Tectonic plates that float on the fluid-like
interior of the Earth.
• Earthquakes are usually caused by
sudden movement of earth plates
Rupture of rocks along a fault
• Faults are localized areas of weakness in
the surface of the Earth, sometimes the
plate boundary itself

4. Shape – Horizontal Layout
BUILDING CONFIGURATION

5. PLAN OF
BUILDING
(Asymmetry should be
avoided)
Asymmetric
buildings undergo
torsion and the
extreme corners of
asymmetric
buildings are
subjected to very
large earthquake
forces

6. Shape – Horizontal Layout
BUILDING CONFIGURATION
Failure Mode

7. Shape – Vertical Configuration
BUILDING CONFIGURATION

8. Shape – Adjacent Buildings
BUILDING CONFIGURATION

9. Shape – Adjacent Buildings
BUILDING CONFIGURATION

10. BUILDINGS HUGGING TO-GETHER

11. Soft-Storey Effect:
STRUCTURAL SIGNIFICANCE

12. Soft-Storey Effect:
STRUCTURAL SIGNIFICANCE

13. STRUCTURAL SIGNIFICANCE
Soft-Storey Effect:

14. Strong Column – Weak Beam
STRUCTURAL SIGNIFICANCE

15. A WEAK COLUMN - STRONG BEAM SYSTEM

16. WEAK COLUMN - STRONG BEAM SYSTEM

17. A WEAK COLUMN - STRONG ROOF SYSTEM

19. Most RC buildings with open
ground storeys that collapsed
showed a very common
practice of poor detailing;
6mm diameter lateral ties in
the columns with 90o hooks
and longitudinal spacing as
large as 30cm.
This did not provide the
required confinement to the
core concrete

20. GENERAL SHAPE OF BUILDING
Very slender
buildings should be
avoided
Inverted pendulum type buildings are
unstable

21. Sudden change in lateral stiffness should be avoided
GENERAL SHAPE OF BUILDING

22. Projections and large overhangs
Avoid long projected
balcony
Large projections
should be avoided

23. Floating columns
Large
overhangs,
projections
and floating
columns
attract large
earthquake
force and
therefore likely
to damage/
collapse due to
instability

24. Separation of dissimilar buildings
To avoid collision,
adjacent dissimilar
buildings should be
separated by a
minimum gap
Type of construction
Min.
gap
per
Storey
(mm)
Load Bearing Building 15
RCC Frame Building 20
Steel Frame Building 30

25. Minimum
depth of
foundation
Plinth band is not
required for
foundation on rock
and hard soil

26. Attachments and Overhangs
All the attachments,
fittings, equipments and
artifacts should be properly
fixed to the ceiling/wall so
that they withstand severe
vibrations
Parapet wall should be
properly secured
Reinfor-
cement in
parapet
wall

27. Heavy mass at the
top should be
avoided
Large water tanks
should be avoided.
Small water tanks,
if provided should
be properly
connected with the
framing system

28. EXCESSIVE TOP CANTILEVERS

29. HEAVY MASS ON TOP:
WATER TANK COLLAPSE WHIPPING EFFECT

30. LOCATION OF A HEAVY MASS ON TOP:
WRONGLY DETAILED

31. Collapse of one-half
of the 14-storey RC
frame residential
apartment building in
Ahmedabad;
the collapsed portion
had a swimming pool
on the roof, unlike the
other half that is
standing

32. Numerous cases of dislodging of the weakly
connected overhead storage water tanks were
observed in the entire earthquake affected
area. Picture shows dislodging of water tank
appendages from atop unfinished and finished
RC frame buildings in Bhuj
Dislodging of water tank appendages from atop unfinished
and finished RC frame buildings in Bhuj

33. Avoid long walls
Depending upon
functional
requirements, either
buttresses or cross
walls can be used to
reduce the
unsupported length

34. Rubble
masonry
To avoid
splitting of
rubble masonry
walls, through
stones should be
provided in
sufficient
number

35. Minimum distance between
openings and corners
• Openings in masonry
walls weaken the walls
• The openings should be
small as far as possible
and should be provided
away from the corners
and each other
• To compensate the loss
of strength due to
openings, 6 mm bar
encased in concrete or
1:3 cement sand mortar
should atleast be
provided around the
openings

36. One of the RC frame multistorey buildings at Ahmedabad that withstood the
earthquake shaking with only minor cracking in the masonry infill walls

37. Based On the above Planning
Configurations Building design should be
done and also resist from the earthquake
forces.
CONCLUSION