Earthquake.pptx

EARTHQUAKE
12/21/2022
MD ABU HENA BASHIR, CEO , Planning Design & Implementation (PDI) - 01878715308

12/21/2022
Introduction To Seismic Resistant Buildings

12/21/2022
Learning Outcome:
i. What are Seismic Resistant Building
ii. What is Earthquake
iii.Different types of Earthquake Waves
iv.Magnitude and Intensity of Earthquake
v. Seismic Resistant Technics
vi.Seismic Analysis
vii.Types of Seismic Analysis
viii.Design Philosophy

Seismic Resistant Buildings
12/21/2022
o Buildings designed to resist the earth quake waves

WHAT IS EARTHQUAKE ?
12/21/2022
 Shaking of the ground due to sudden release of energy in earth crust.

Causes of Earthquake
12/21/2022
• Tectonic Plate movement (95%)
• Other Disturbances ( Like as Volcanic eruptions, rock falls, landslides and explosions) (5% )

The Focus /Hypocenter and Epicenter of an Earthquake
12/21/2022
Focus : Source of a given set of earthquakes. Point of faulting and first point of releasing of energy.
Epicenter : Point on earth surface directly above of focus.

Earthquake waves
12/21/2022
Earth
Waves
Body waves
(Travel through the interior of mass in
which they are generated)
Surface wave
(Travel only along the surface)
P waves
S waves
Love
waves
Rayleigh
waves

Earthquake waves continuous
12/21/2022
P Wave
 Longitudinal wave (as sound)
 Zones of compression and rarefaction
 Continuous push/pull on the ground
 Can pass through solids , liquids , gases
 Fastest of all waves
 8 km/sec
S Wave
 Secondary type
 Transverse type
 Particles move at right angle to direction of propagation
 Travels only through material the resist a change in shape
 2 miles/sec

Earthquake waves continuous
12/21/2022
Love Wave
 No vertical movement
 Move the ground from side to side parallel to the earth’s
surface (at right angles to the direction of propagation.)
 Produces horizontal shaking
 Travels faster than Rayleigh waves (10,000 miles/hour)
Rayleigh waves
 Disturbed materials moves both horizontally
and vertically in a vertical plane pointing in
the direction in which the waves travelling.
 Emanating outward from the epicenter of an
earthquake travel along the surface of the
earth.
 At about 10 times the speed of sound in air
(0.340 km/s), that is ~3 km/s.

Measurement Of Earthquake
12/21/2022
There are two types of measurement of an
Earthquake like as,
1. Magnitude
2. Intensity

Magnitude of Earthquake
12/21/2022
 Represent the amount of energy released into the earth’s crust.
 Richter scale is used to measure the magnitude of Earthquake.
 Based on the maximum amplitude of the seismic wave at the distance 100km from epicenter.

Richter Scale
12/21/2022
𝑀𝐿 = 𝑙𝑜𝑔10𝐴 − 𝑙𝑜𝑔10𝐴0 ∆
𝑀𝐿 = 𝑙𝑜𝑔10(
𝐴
𝐴0 ∆
)
Where,
𝑀𝐿= Richter or local magnitude value
A = Amplitude of largest seismic wave
𝐴0 =Amplitude of smallest seismic wave
∆ = Epicenter distance of earthquake

Richter Scale
12/21/2022

Richter Scale
12/21/2022
Magnitude vs. ground motion and energy
Magnitude change Ground motion change
(Displacement)
Energy change
0.1 1.3 Times About 1.4 Times
1.0 10.0 Times About 32.0 times

Richter Scale
12/21/2022
Different Earthquake Magnitudes on Richter Scale
Magnitude Description Earthquake effect
Less than 2.0 Minor No felt by people, recorded by
seismographs
2.0 – 6.0 Moderate Cause damage to poorly constructed
buildings
6.0 – 8.0 Major Most buildings partially or completely
collapse
8.0 - 10 Great Major damage to buildings, structures
likely to be destroyed

Intensity of Earthquake
12/21/2022
 Measure of effect of earthquake on human beings, structures and earth surface
 Modified Mercalli intensity scale used
 12 degree of intensity
Modified Mercalli intensity scale:
Degree Earthquake Effect
I Not Felt
II Felt by person at rest
III Felt indoors, Vibration like passing of light truck
IV Hanging objects swing, Vibration like passing of heavy truck
V Felt outdoors, Liquid disturbed some spilled
VI Felt by all, Furnitures overturned
VII Difficult to stand, Furnitures are broken
VIII Steering of cars affected, change of temp. of spring water
IX General panic, general damage to foundation of frame structure, Underground pipe broken
X Frame structures destroyed, large landslides, Wood structures bridge destroyed
XI Rails bent greatly, Underground pipes completely out of services
XII Total damages, Objects thrown into air

How to make buildings seismic resistant?
12/21/2022
By Designing the buildings
 More stronger and
 More flexible

Strength - Techniques
12/21/2022
 Moment Resisting frames.
 Combinations of beams and columns ( Beams rigidly
connected to the columns).
 Widely used in medium rise structures.

12/21/2022
Braced frames
 Structural system consists of diagonal; steel section
 Primarily designed to resist wind and earthquake forces
 Eccentric type of bracing is commonly used in seismic
regions

12/21/2022
 Shear walls
 Vertical elements of horizontal force
resisting system
 Generally used in high rise buildings
where seismic and wind forces are high

Types of Dampers
12/21/2022
 Viscous damper
 Hydraulic device – Dissipate the kinetic energy of seismic waves and cushion
the impact between structures
 Well suited for heavy load bearing structures such as bridges buildings and mass
structures

Types of Dampers
12/21/2022
 Tuned mass damper (TMD)
 A device mounted in structures to reduce
the amplitude of seismic vibrations

Types of Dampers
12/21/2022
 Friction damper
 Consists of moving parts that will slide over each other during a strong
earthquake
 These dampers allows building to move elastically and dissipate the energy of
Earthquake

Flexibility - Techniques
12/21/2022
 Base Isolation
 Detaching the super structure from sub structure –
Installing shock absorber or bearings between them
 Best suitable for medium rise structures like public
buildings

Types of Bearings
12/21/2022
 Rubber bearings
 Made from layers of rubber with thin steel plate on
the top and bottom

Types of Bearings
12/21/2022
 Friction pendulum bearings
 Made from two horizontal steel plates that can
slide over each other because of their shape and an
additional articulated slider

Seismic Analysis
12/21/2022
 Calculation of the response of a structure to earthquake

Different Seismic Analysis Method
12/21/2022
Seismic
Analysis
Static
Analysis
Dynamic
Analysis
Linear Static Analysis
Non – linear Static Analysis
Linear Dynamic Analysis
Non-linear Dynamic Analysis

Linear Static Analysis
12/21/2022
 Equivalent static method
 The design base shear for entire building calculated – Distributed
along the height of building

Non-linear Static Analysis
12/21/2022
 Pushover analysis
 Capacity or pushover curve – Total seismic force against deflection

Linear Dynamic Analysis
12/21/2022
 Response spectrum method
 Provides the maximum seismic response of structure – By measuring
the natural mode of vibration.

Non-linear Dynamic Analysis
12/21/2022
MD ABU HENA BASHIR, CEO , Planning Design & Implementation (PDI) -
01878715308
 Time history analysis
 Provides the structural response of the structure
with respect to ground motion records

Design Philosophy
12/21/2022
Earthquake
Intensity
Design description
Under minor
shaking
Main load carrying members should
not damage, other parts may sustain
repairable damage
Under moderate
shaking
Main load carrying members may
sustain repairable damage, other parts
may be replaced after damage
Under major
shaking
Main load carrying members may
sustain irreparable damage, but the
building should not collapse

Earthquake.pptx

Recommended

Recommended

More Related Content

Similar to Earthquake.pptx

Similar to Earthquake.pptx (20)

Recently uploaded

Recently uploaded (20)

Earthquake.pptx