The presentation covers the scenario post a hazard of Earthquake turned into a disaster. Further, it includes the basic terminology, dynamics of EQ event, and suggests remedial practices for structural and non-structural elements of a building. Purpose the compilation is to sensitize learners.
3. What is an Earthquake?
A Vibrations produced in the earth’s crust
when rock’s elastic strain has ruptured and
rebounded
4. What causes an earthquake?
Earthquakes are usually caused by sudden
movement on faults
5. What causes an earthquake?
A sudden release of energy accumulated in deformed
rocks causing the ground to tremble or shake.
Causes rupturing or brittle failure of crustal rocks.
Energy is released.
Movement of fault blocks takes place along a
fault plane.
6. After energy is released, friction between the adjacent fault
blocks prevents further movement. Stress resumes and
builds up again.
Friction between the blocks is overcome. Another earthquake
occurs.
26. Site Effect
The shape, amplitude, and the duration of a seismic movement
are affected, among other things, by its magnitude, the
distance to the hypocenter, and the local site conditions
38. Unsuitable plan Suitable plan
In order to make unsuitable building plans seismically
acceptable, they need to be divided into a number of
rectangular or symmetrical units.
Building Configuration
Pounding Effect
40. b
h
h
b
Height of the building should be less than 3b
Building Configuration
contd....
41. Ideal Earthquake Resistant Building
Small mass
Low Height-to-base ratio
Low center of mass relative to the ground
Balanced lateral resistance
Direct load paths
Symmetrical Plan
Uniform section and elevation
Uniform floor heights, and
Maximum rotational resistance
Short spans
46. No Yes
Interaction of Structural Elements of
Different Stiffness
Seismic Joint
Proper Design OR
Strengthening of Flexible Element
47. Significant difference between
stiffness in x and y Balanced stiffness in x and y
Asymmetric arrangement of Vertical
element (Torsional Vibration)
symmetric arrangement of
Vertical element
No Yes
48. Small contribution of Shear wall in
Torsional resistance
Increase of Torsional resistance
Incorrectly supported columns Uniform Column
No Yes
49. Unclear Frame Behavior Good Frame Behavior
in x and y
Strong beam-weak Column
(column Failure mechanism)
Weak (comparatively) beam-strong
Column (Beam Failure mechanism)
No Yes
52. Masonry Buildings
contd.….
Stitch and band give more integrity to the building elements
and protect the building from corner opening and out of
plane failure
55. RC Buildings
contd…..
Failure of building at beam column
joints
Joint Reinforcing
Unreinforced beam-column joints may not be able to
develop the strength of the connected members, and this can
lead to sudden brittle failure of the joint
79. Significance: Life Safety
If a ten-rupees
flowerpot , not
fastened well to the
building, falls on
someone’s head, it
can be a killer!
80. Significance: Property Loss
Very important in case of
commercial and Institutional
buildings
Property losses in 25
commercial buildings due to the
1971 San Fernando earthquake:
Structural damage 3%
Electrical and mechanical 7%
Exterior finishes 34%
interior finishes 56%.
81. Significance: Loss of function
Critical facility
Hospital
Telecommunication etc.
82. Mitigation Measures :
Removal
A hazardous material that could be spilled,
could be stored perfectly well outside the
premises
One solution would be stronger fastening or
the use of stronger supports,
But the most effective solution would be
removal and replacement
83. A very heavy
object on top of a
shelf could fall and
seriously injure
someone
If it is relocated to
a floor-level shelf
it would not
represent any
danger to human
lives or to property. Store large, heavy or fragile objects on
lower shelves or in low closed cabinets
Relocation
84. Anchorage of Battery Rack+ Anchorage of Book
shelve SOURCE: EERI
Anchorage
86. Restricted Mobilization
It does not matter if
the cylinders shift as
long as they do not fall
and break their valves.
Sometimes back-up
power generators are
mounted on springs to
reduce the noise and
vibrations when they
are working, but these
springs would amplify
ground motion.
87. Flexible Couplings
The use of flexible piping in
critical areas such as
between buildings and
equipment helps to prevent
breakage
PAHO/WHO
90. Substitution
A heavy tiled roof does not only make the roof of a
building heavy, it is also more susceptible to
earthquake shaking. The individual tiles tend to come
off, creating a hazard for people and for objects.
One solution would be to change it for a lighter, safer
roofing material.
91. Modification
Rolls of transparent adhesive plastic
may be used to cover the inside
surfaces and prevent them from
shattering and threatening those
inside.
93. Redundancy
Redundancy or duplication of items is
advisable.
An emergency response plan requiring
storage of emergency supplies is a good
idea.
It is possible/necessary to store extra
quantities of certain products, providing a
certain level of independence from external
supply which could be interrupted in the
case of earthquakes.