earthquake resisting structure

1. DEPARTMENT OF,
CIVIL ENGINEERING

3. CONTENTS
1.BASIC-
1.1 Introduction
1,2 Zones
1.3 Faults
1.4 Frequency
1.5 Effects
2.CONCEPT OF BASE ISOLATION –
2.1 Techniques
2.2 Structures
2.3 Theory
2.4 Types
2.5 Suitability
3.INTENSITY
4.SOIL BEARING CAPACITY & TESTS
5.BHUJ EARTHQUAKE
6.CONCLUSION

4. BASIC OF SEISMOLOGY
1.1 Introduction
An Earthquake is the result of a sudden release of
energy in the Earths crust that creates seismic waves . The
seismicity , seismic activity of an area refers to the frequency ,
type & size earthquakes experienced over a period of time.
Earthquake are measured using observation from
seismometers, The moment magnitude is the most common
scale on which Earthquake larger than approximately 5
reported by national seismological observatories are measured
mostly on the local magnitude scale ,also referred to as the
Richter scale. These two scales are numerically similar over
their range of validity. Magnitude 7 & over potentially causes
serious damage over larger areas ,depending on their depth .

5. The largest earthquakes in historic times have been of
magnitude slightly over 9 although there is no limit to the
possible magnitude. The most recent large Earthquake of
magnitude 9.0 or larger was a 9.0 magnitude Earthquake in
Japan in 2001 ( as of October 2012 ) , & it was the largest
Japnese Earthquake since records began.
At the Earth surface , Earthquakes manifest themselves
by shaking & sometimes displacement of the ground . When
the epicenter of a large Earthquake is located offshore , the sea
bed may be displaced sufficiently to cause a tsunami
Earthquake can also trigger landslides ,& occasionally
volcanic activity.

6. 1.2 Earthquake Zones in India

7. Earthquake Fault Types.
There are three main types of fault, all of which may cause an earthquake
•Normal fault :-
Normal fault are example of dip - slip, where the displacement along the
fault is in the direction of dip and movement on them involves a vertical
component.
•Reverse Fault :-
Reverse faults occur in areas where the crust is being shortened such as
at a convergent boundary.
•Strike Fault :-
Strike - slip faults are steep structures where the two sides of the fault
slip horizontally past each other; transform boundaries are a particular
type of strike - slip fault.

8. International Earthquake Frequency

9. YEAR PLACE MAGNITUDE LOSS OF LIFE
1950 ARUNACHAL PRADESH 8.5 1,526
1976 TANGSHNA, CHINA 8.2 2,42,000
1980 ITALY 6.9 2,735
1990 IRAN 7.4 40,000
1993
KILLARI, LATUR
MAHARASHTRA
6.9 30,000
2001 BHUJ, GUJRAT 7.7 20,000
2002 AFGANISTHAN 6.1 1,000
2005 KASHMIR 7.6 87,000
2011 FUKUSHIMA, JAPAN 8.9 13,000
2011 TURKEY 7.2 1,385
2011 INDONESIA 8.6 1,250
Some Major Earthquake in world

10. Effects of earthquakes
The effect of earthquakes include, but are not limited to, the following :
•Shaking and ground rupture
Shaking and ground rupture are the main effects
created by earthquakes, principally resulting in
more less severe damage to buildings and other
rigid structures. The severity of the local effects
depends on the complex .

11. •Landslides and avalanches
Earthquake, along with serve storms, volcanic activity, coastal wave attack,
and wildfires, can produce slope instability leading to landslides, an major geological
hazard. Landslide danger may persist while emergency personnel are attepting rescue.
•FIRES
Earthquakes can cause fires by damaging electrical power or gas lines. In the
event of water mains rupturing and loss of pressure, it may also become different to
stop the spread of a fire once it has started. For example, more deaths in the 1906 Sam
Francisco earthquake were caused by fire than by earthquake itself.

12. •Soil Liquefaction
Soil liquefaction occurs when, because of the shaking, water - saturated
granular material (such as sand) temporarily loses its strength and transforms from a
solid to a liquid.
TSUNAMI
Tsunamis are long - wavelength, long period sea waves produced by the
sudden or abrupt movement of large volumes of water. In the open ocean the distance
between waves crests can surpass 100 kilometers and the wave periods can vary from
five minutes to one hour. Such tsunamis travel 600-800 kilometers per hour (373-497
miles per hour).

13. •Floods
A food is and overflow of any amount of water that reaches land. Floods occur
usually when the volume of water within a body of water, such as a river or lake,
exceeds the total capacity of the formation, and as a result some of the water flows or
sites outside of the normal perimeter of the body.
Human Impact
An earthquake may cause injury and loss of life, road and bride
damage, general collapse or destabilization (potentially leading to future
collapse) of building. The aftermath may bring disease, lack of basic
necessities, and higher insurance premiums.

14. CONCEPT OF BASE ISOLATION
It is easiest to see the principle at work by referring
directly to the most widely used of these advanced techniques,
known as base isolation. A base isolated structure is supported
by a series of bearing pads, which are placed between the
buildings and building foundation.
.

15. BASE ISOLATION TECHNIQUE
This concept of base isolation is explained through an example
building resting on frictionless rollers. When the ground shakes, the
rollers freely roll, but he building above does not move. Thus, no
force is transferred to the building due to the shaking of the ground;
simply, the building does not experience the earthquake.
Now, if the same building is rested on the flexible pads that
offer resistance against lateral movement 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 experienced by the
building built directly on ground, namely a fixed base building.
The flexible pads are called base isolators, whereas the structures
protected by means of these devices are called base isolated
buildings

16. RESPONSE BASE ISOLATED BUILDING
The base - isolated building retains its original, rectangular shape.
The base isolated building itself escapes the deformation and damage-
which implies that the internal forces acting on the base isolated building
have been reduced.
STRUCTURE DESCRIPTION

17. BASE DIAGRAM OF ISOLATOR
The isolation system is placed at the foundation level. The foundation
plinths are connected each other by concrete beams in order to realized the rigid
foundation plane which is isolated structure lays on rigid concrete framed
obtained by concrete beam with variable section. The beam are realized by a
precast concrete framework the realizes the designed variable section, allows
the positioning of the frame on isolated bars and inserted the reinforcement
steel gives the final reinforced concrete supporting beams directly on the
seismic.

18. Theory of Isolation
Most of Civil engineering structures fall in ranges of 0.1 to 1 min time
period which create resonance with dominant time period of earthquake. Due to
this more energy get imparted is structure during earthquake and it get damage.
BASE ISOLATORS
Building resting on frictionless rollers when the ground shakes the
roller freely rolls but building above does not move. Thus no force is transfer in
building due to shaking of the ground. Simply the building does not experience
the earthquake.
The base isolator looks like rubber pads, although there are other types
that are based on sliding of one part of building relative to other. A rubber
sandwiched together with layer of steel. In the middle of solid lead 'plug' on
the top and bottom, bearing is fitted with steel plates which are used to attach
the bearing to the building & foundation.

19. TYPES OF BASE ISOLATORS
The most common used types of base isolators in building are:-
•Laminated rubber bearing.
•High dumping rubber bearing (HDRB).
•Frictional pendulum system bearing .
•Lead rubber bearing.
BASE ISOLATORS
The most common used types of base isolators in building are
following :-
•Laminated rubber bearing.
•High dumping rubber bearing.

20. 1.laminated rubber bearing
2.high dumping rubber bearing (HDRB)

21. SUITABILITY OF BASE ISOLATION
Suitability of Base Isolation:
•Base isolation are useful for important structures where damage
can't be tolerated such as Hospitals, Historical buildings,
communication building and towers, bridges.
•Hospitals, communication building and towers, bridges are
required to in working condition to provide relief to earthquake
victims.
•Historical building or monumental structures are having historic
importance so damage to such structures are also can't be
tolerated.
•Base isolation is useful for structure on relatively stiff ground
with rigid structure. It proves ineffective for flexible structure. It
is generally assumed that it is useful for structure up to 6 floors.

22. INTENSITY
In seismology a scale of seismic intensity is a way of measuring
or rating the effects of an earthquake at different sites.
The Modified Mercalli Intensity Scale is commonly used in the
United States by seismologists seeking information on the
severity of earthquake effects. Intensity ratings are expressed
as Roman numerals between I at the low end and XII at the
high end.
The Intensity Scale differs from the Richter Magnitude Scale in
that the effects of any one earthquake vary greatly from place
to place, so there may be many Intensity values measured
from one earthquake. Each earthquake, on the other hand,
should have just one Magnitude, although the several
methods of estimating it will yield slightly different values .

23. STEPS OF INTENSITY :-
I. People do not feel any Earth movement.
II. A few people might notice movement if they are at rest and/or on the upper
floors of tall buildings.
III. Many people indoors feel movement. Hanging objects swing back and forth.
People outdoors might not realize that an earthquake is occurring.
IV. Most people indoors feel movement. Hanging objects swing. Dishes, windows,
and doors rattle. The earthquake feels like a heavy truck hitting the walls. A few
people outdoors may feel movement. Parked cars rock.
V. Almost everyone feels movement. Sleeping people are awakened. Doors swing
open or close. Dishes are broken. Pictures on the wall move. Small objects move
or are turned over. Trees might shake. Liquids might spill out of open containers.
VI. Everyone feels movement. People have trouble walking. Objects fall from
shelves. Pictures fall off walls. Furniture moves. Plaster in walls might crack. Trees
and bushes shake. Damage is slight in poorly built buildings. No structural damage.
VII. People have difficulty standing. Drivers feel their cars shaking. Some furniture
breaks. Loose bricks fall from buildings. Damage is slight to moderate in well-built
buildings; considerable in poorly built buildings.

24. IX. Well-built buildings suffer considerable damage. Houses that are not bolted
down move off their foundations. Some underground pipes are broken. The
ground cracks. Reservoirs suffer serious damage.
X. Most buildings and their foundations are destroyed. Some bridges are
destroyed. Dams are seriously damaged. Large landslides occur. Water is thrown
on the banks of canals, rivers, lakes. The ground cracks in large areas. Railroad
tracks are bent slightly.
XI. Most buildings collapse. Some bridges are destroyed. Large cracks appear in the
ground. Underground pipelines are destroyed. Railroad tracks are badly bent.
XII. Almost everything is destroyed. Objects are thrown into the air. The ground
moves in waves or ripples. Large amounts of rock may move.
VIII. Drivers have trouble steering. Houses that are not bolted down might shift on
their foundations. Tall structures such as towers and chimneys might twist and fall.
Well-built buildings suffer slight damage. Poorly built structures suffer severe
damage. Tree branches break. Hillsides might crack if the ground is wet. Water
levels in wells might change.

25. SOIL BEARING CAPACITY
During rainy season, immediately after rain, when we stepped into soil
soften by the rain, our shoe penetrates into the soil. The soil squeezes out from
under our shoe and emerges around the sides of our shoe. During this process
we lose our balance till the soil below the surface supports our weight and
provides us stability.
The soil below our shoe just “gave way”. This giving way or running away
of soil is called bearing capacity failure by Geotechnical engineers. Bearing
capacity failure is a failure by shear. So knowledge of bearing capacity of any
soil before construction of structure is very essential.
Factors Affecting Bearing Capacity of Soils
(i)Type of soil
(ii) Physical characteristics of foundation
(iii) Soil properties
(iv) Type of foundation
(v) Water table
(vi) Amount of settlement
(vii) Eccentricity of loading.

26. BHUJ EARTHQUAKE
The first historical kutch earthquake to attract international attention was the1819
allah bund earthquake ,which created a 6m high and 6 km wide natural dam across the
puran river ,which enters the rann of kutch from the north. A lake ,30km in diameter,
lake sindri , was formed south of the allah bund. A lake was also formed north of the
bund in 1819 ,which drained in 1826 when a torrent broke through several artificial
dams on the puran and cut a gorge through the bund , flooding regions
downstream.damage to bhuj and anjar during the 1819 earthquake was substancial.
the most deviating earthquake .of january 26,2001,that struck at 8:46 am ist in the
kutch region of gujarat,in india ,was an eye opener for structural engineers and
designers. The devastation was major in terms of lives lost, injuries suffered, as well as
structural collapses and economic losses. The entire kutch region was extensively
damage and several towns and villages , such as bhuj , anjar , vondh , gandhinagar ,
kandla port , morbid , ahmedabad, rajkot,and bhachau, sustained wide-spread
destruction. Numerous newly constructed buildings collapsed leading to extensive
causalities. The earthquake is subsequently reffered to as the kutch earthquake or the
bhuj earthquake.

27. EFFECTS
The death toll in the Kutch region was 12,300. Bhuj, which was situated only
20 km away from the epicenter, was devastated. Considerable damage also
occurred in Bhachau and Anjar with hundreds of villages flattened in Taluka of
Anjar, Bhuj and Bhachau. Over a million structures were damaged or destroyed,
including many historic buildings and tourist attractions. The quake destroyed
around 40% of homes, eight schools, two hospitals and 4 km of road in Bhuj, and
partly destroyed the city's historic Swaminarayan temple and historic fort as
well Prag Mahal and Aina Mahal.
In Ahmedabad, Gujarat's commercial capital with a population of 5.6 million, as
many as 50 multi-story buildings collapsed and several hundred people were
killed. Total property damage was estimated at $5.5 billion and rising. In Kutch,
the earthquake destroyed about 60% of food and water supplies and around
258,000 houses–90% of the district's housing stock. The biggest setback was the
total demolition of the Bhuj Civil hospital. The Indian military provided emergency
support which was later augmented by the International Federation of Red Cross
and Red Crescent Society. A temporary Red Cross hospital remained in Bhuj to
provide care while a replacement hospital was built.

28. RECONSTRUCTION :-
Four months after the earthquake the Gujarat
government announced the Gujarat Earthquake
Reconstruction and Rehabilitation Policy. The
policy proposed a different approach to urban and
rural construction with the estimated cost of
rebuilding to be US$1.77 billion.
The main objectives of the policy included
repairing, building, and strengthening houses and
public buildings. Other objectives included the
revival of the economy, health support, and
reconstruction of the community and social
infrastructure.

29. HOUSING :-
The housing policy focused on the removal of rubble, setting up temporary shelters,
full reconstruction of damaged houses, and the retrofitting of undamaged units.The
policy established a community-driven housing recovery process. The communities
affected by the earthquake were given the option for complete or partial relocation
to in-situ reconstruction.The total number of eligible houses to be repaired was
929,682 and the total number of eligible houses to be reconstructed was 213,685. By
2003, 882,896 (94%) houses were repaired and 113,271 (53%) were reconstructed.
CITY PLANNING :-
The Environmental Planning Collaborative (EPC) was commissioned to provide a new
city plan for the city of Bhuj. The plan focused on creating a wider roadway network to
provide emergency access to the city. The EPC used land readjustment (LR) in the form
of eight town planning schemes. This was implemented by deducting land from private
lot sizes to create adequate public land for the widening of roadways.The remaining
land was readjusted and given back to the original owners as final.

30. CONCLUSION
•Conventional earthquake design is necessary and useful for structure
where damage can be tolerated in event of Maximum scredible event.
•Base isolation and Energy dissipation devices are useful for importance
structures where damage can't be tolerated such as Hospitals, Historical
buildings.
•Communication building and towers, bridges as these structures are
required to use for relief to earthquake victims (except historical
building).
•Base isolation lengthens the time period of the structure, and thus
reduces pseudo acceleration as compare to non-isolated structure which
results in reduction in base shear during shaking of ground.
•Base isolation is useful for structure on relatively stiff ground with rigid
structure. It proves ineffective for flexible structure. It is generally
assumed that it is useful for structure up to 6 floor.
•Energy dissipation devices are most useful for flexible system.
•Both Isolation and energy dissipation devices are proves costly as
compared to Conventional earthquake design, so used only for important
structures.

31. THANK
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