Base isolation- Project of civil engineering/ last year Earthquake resistance wooden house

1. EARTHQUAKE RESISTANCE
WOODEN HOUSE
PROJECT CIVIL – 6THARCHITECT - TWINKAL JAMBU

2. Earthquake:
 Earthquake by itself, is not a disaster, it is natural phenomenon result from
ground movement , sometimes violent.
 These produce surface waves, which cause vibration of the ground and
structure on top.
 Depending on the characteristics of these vibrations, the ground may
develop cracks, fissures and settlements.
 It measure in seismometer
 The possible risk of loss of life adds a very
serious dimension to seismic design,
putting a moral responsibility on structural
engineers.
 In recent times, many new systems have
been developed, either to reduce the
earthquake forces acting on the structure
or to absorb a part of seismic energy.
 One of the most widely implemented and
accepted systems is base isolation.

3. Base isolation
• Base isolation is one of the most widely accepted seismic protection
systems in earthquake prone areas.
• It mitigates the effect of an earthquake by essentially isolating the
structure from potentially dangerous ground motions.
• Seismic isolation is a design strategy, which uncouples the structure
for the damaging effects of the ground motion
 The term isolation refers to reduced interaction between structure
and the ground. When the seismic isolation system is located
under the structure, it is referred as “base isolation”.

4. • The other purpose of an isolation system is to provide an additional
means of energy dissipation, thereby reducing the transmitted
acceleration into the superstructure.
• The decoupling allows the building to behave more flexibly which
improves its response to an earthquake.
Base isolation

5. Purpose of Base Isolation
• Wind and Earthquake are the most predominant loads that
demands lateral design of a structure.
• Again, earthquake load is not controllable and it is not practical to
design a structure for an indefinite seismic demand.
• The inertial forces caused due to earthquake is directly proportional
to the mass of structure and the ground acceleration. Increasing
ductility of the building or increasing the elastic strength of the
structure is the most conventional method of handling seismic
demand.
• Engineer has to increase the capacity exceed the demand
 Base isolation takes an opposite approach, i.e. to reduce the
seismic demand instead of increasing the capacity.
 Controlling ground motion is impossible, but we can modify the
demand on structure by preventing/reducing the motions being
transferred to the structure from foundations.

6. TYPES OF
ISOLATION
SYSTEM
Elastomeric
bearings
springs
Ball & roller
bearings
Flat slider
bearings
Lead rubber
bearings
Curved slider
bearings
Type of Base Isolation systems
There are Six major types of base isolation devices which are
widely adopted for seismic base isolation.

7. Elastomeric Bearings
Springs isolators

8. Ball & Roller Bearings
Flat Slider Bearings

9. Advantages of Base isolation
• Reduced the seismic demand of structure, thereby reducing the cost of
structure.
• Lesser displacements during an earthquake.
• Improves safety of
Structures
• Reduced the damages
caused during an
earthquake. This helps in
maintaining the
performance of structure
after event.
• Enhances the
performance of structure
under seismic loads.
• Preservation of property
Disadvantages
Cost : of devices on their own was 2%;
total cost of the base isolation system was 3% of total construction cost.

10. Base isolation in real buildings
 In India, base isolation technique was first demonstrated after the
1993 Killari (Maharashtra) Earthquake.
 Two single storey buildings in newly relocated Killari town were
built with rubber base isolators resting on hard ground.
 After the 2001 Bhuj (Gujarat) earthquake, the four-storey Bhuj
Hospital building was built with base isolation technique.
 All were brick masonry buildings with
concrete roof.
 The figure shows the base isolation
technique used in the Bhuj Hospital
building with the help of Base Isolators.

11. Base isolation in real buildings

12. Case study
Name : Wooden house
Location : madgao, goa, india

13. Vibro-SMR in Model

14. Process of model making

15. Without isolator
With isolator

16. Material
• Spring
• Steel
• Wood
Conclusion
 Seismic base isolation method has proved to be a reliable method
of earthquake resistant Design.
 The success of this method is largely attributed to the development
of isolation devices and proper planning.
 Adaptable isolation systems are required to be effective during a
wide range of seismic events.
 Efforts are required to find the solutions for the situations like near
fault regions where wide variety of earthquake motions may occur.

17. The End. . . . . . . .