DIFFERENCE BETWEEN
EARTHQUAKE AND WIND?
DYNAMIC ACTIONS ON BUILDINGS
EARTHQUAKE Vs WIND
Difference in the design effects on a building during natural actions
of
a)Earthquake Ground Movement at base
b)Wind Pressure on exposed area
19/09/2020 11:09:57 ST2102 ASEISMIC DESIGN OF STRUCTURES 2
DYNAMIC ACTIONS ON BUILDINGS
EARTHQUAKE Vs WIND
Nature of temporal variations of design actions
a)Earthquake Ground Motion – zero mean
b)Wind Pressure – non-zero mean
19/09/2020 11:10:38 ST2102 ASEISMIC DESIGN OF STRUCTURES 3
WHETHER THE BUILDING SHOULD BE
DESIGNED FOR EARTHQUAKE/WIND OR
BOTH?
WHY?
WHETHER WIND/EARTHQUAKE
In context to IS 1893
(Part I ):2002
Page No: 13
19/09/2020 11:12:48 ST2102 ASEISMIC DESIGN OF STRUCTURES 5
WHETHER WIND/EARTHQUAKE
All other hazards FORCE DISPLACEMENT
impose force LOADING LOADING
loading
Earthquake shaking
imposes displacement
loading on the building
19/09/2020 11:12:57 ST2102 ASEISMIC DESIGN OF STRUCTURES 6
WHETHER WIND/EARTHQUAKE
19/09/2020 11:13:49 ST2102 ASEISMIC DESIGN OF STRUCTURES 7
UNIT 1
INTRODUCTION
UNIT 1
INTRODUCTION
Syllabus
Introduction to engineering seismology - various
theories - measurement scales - vibration measuring
instruments - Past earthquakes in India and world -
Response spectrum - significance - construction & use
19/09/2020 11:15:19 ST2102 ASEISMIC DESIGN OF STRUCTURES 9
INTRODUCTION TO SEISMOLOGY
Seismology
Seismology is the study of the generation,
propagation and recording of elastic wave in the earth,
and the sources that produce them
19/09/2020 11:15:21 ST2102 ASEISMIC DESIGN OF STRUCTURES 10
INTRODUCTION TO SEISMOLOGY
Classification Based on Source
Natural Source Man-Made Source
Tectonic Earthquake Controlled Earthquake(Explosives)
Volcanic Earthquake Reservoir Induced Earthquake
Rock falls/Collapse of Cavity Mining Induces Earthquake
Cultural Noise (Industry, Traffic,
Microseism
etc)
90% of earthquake results from Tectonic event – Movement of Plate
19/09/2020 11:15:23 ST2102 ASEISMIC DESIGN OF STRUCTURES 11
INTRODUCTION TO SEISMOLOGY
Earthquake (Seismic)
An earthquake is a sudden tremor or the movement of
the earth crust, which originates naturally at or below the
surface
19/09/2020 11:16:10 ST2102 ASEISMIC DESIGN OF STRUCTURES 12
INTRODUCTION TO SEISMOLOGY
Internal Structure of Earth
Geosphere Sequence of shells or layers inside the earth
Barysphere (Core) includes inner core and outer core
Asthenosphere (Mantle) includes lower mantle and
upper mantle
Lithosphere (Crust) outer solid shell
19/09/2020 11:17:55 ST2102 ASEISMIC DESIGN OF STRUCTURES 13
14 P ST2102 ASEISMIC DESIGN OF STRUCTURES 19/09/2020 11:18:15
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INTRODUCTION TO SEISMOLOGY
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VARIOUS THEORIES
Elastic Rebound Theory
Rocks move opposite direction - subjected to force
and shift - energy accumulates - deform - accumulated
energy is more than the internal strength - sudden
movement - along the fault - releasing the accumulated
energy as the earthquake
19/09/2020 11:19:19 ST2102 ASEISMIC DESIGN OF STRUCTURES 15
VARIOUS THEORIES
Elastic Rebound Theory
19/09/2020 11:19:49 ST2102 ASEISMIC DESIGN OF STRUCTURES 16
VARIOUS THEORIES
Plate Tectonic Theory
Tectonic - study of deformation of earth material
Plate - Lithosphere(Outermost layer) - 100km thick -
behave like a rigid shell
Heating and cooling - Barysphere and Asthenosphere
- convention current - Lithosphere moves - different
velocity - 2cm/year - energy accumulates
Accumulated stress exceeds the strength of the rock -
rock brakes – releasing the energy as earthquake
19/09/2020 11:21:11 ST2102 ASEISMIC DESIGN OF STRUCTURES 17
VARIOUS THEORIES
Pangea
19/09/2020 11:21:50 ST2102 ASEISMIC DESIGN OF STRUCTURES 18
VARIOUS THEORIES
19/09/2020 11:23:02 ST2102 ASEISMIC DESIGN OF STRUCTURES 19
VARIOUS THEORIES
Antarctica
Major
Africa & Minor Tectonic Plate
Eurasia Minor
India Tectonic
Australia Plate
Arabia
Philippines Major
North America Tectonic
South America
Plate
Pacific
Nazca
Cocos
Scotia
Caribbean
Juan de Fuca
19/09/2020 11:23:35 ST2102 ASEISMIC DESIGN OF STRUCTURES 20
VARIOUS THEORIES
World Seismotectonic
Major and minor
lithospheric plates
(The arrows indicate
relative velocities in
mm/year at different type
of active plate margin)
19/09/2020 11:24:27 ST2102 ASEISMIC DESIGN OF STRUCTURES 21
VARIOUS THEORIES
Indian Seismotectonic
Tectonic map showing the
major geomorphologic feature
in India and adjoining region
19/09/2020 11:24:51 ST2102 ASEISMIC DESIGN OF STRUCTURES 22
VARIOUS THEORIES
❑ Lithospheric plates move relative to each other
❑ Earthquake occurs along these fault
Plate Boundaries
Types of plate boundaries:
Divergent boundaries
Convergent boundaries
Transform boundaries
19/09/2020 11:25:24 ST2102 ASEISMIC DESIGN OF STRUCTURES 23
VARIOUS THEORIES
Plate
boundaries
Convergent Divergent Transform
boundaries boundaries boundaries
Oceanic-contin Continental-co
Oceanic-ocean
ental ntinental
ic boundaries
boundaries boundaries
19/09/2020 11:25:39 ST2102 ASEISMIC DESIGN OF STRUCTURES 24
VARIOUS THEORIES
Convergent Boundaries
Crust destruction occurs as plates move towards each
other and one plate sinks under another
Indonesia earthquake 26th December 2004
19/09/2020 11:26:10 ST2102 ASEISMIC DESIGN OF STRUCTURES 25
VARIOUS THEORIES
Oceanic-continental
boundaries
Oceanic-oceanic
boundaries
Continental-continental
boundaries
19/09/2020 11:26:50 ST2102 ASEISMIC DESIGN OF STRUCTURES 26
VARIOUS THEORIES
Divergent Boundaries
New crust is created as the plates pull away from
each other
Mid-Atlantic ridge (Rate of spreading is 2.5 cm/year)
19/09/2020 11:27:25 ST2102 ASEISMIC DESIGN OF STRUCTURES 27
VARIOUS THEORIES
Transform Boundaries
Crust slide horizontally
San Andreas Fault zone in Califormia
19/09/2020 11:28:42 ST2102 ASEISMIC DESIGN OF STRUCTURES 28
VARIOUS THEORIES
Movement of Indian plate
19/09/2020 11:29:45 ST2102 ASEISMIC DESIGN OF STRUCTURES 29
VARIOUS THEORIES
Faults
A fracture along which the blocks of crust on either
side have moved relative to one another parallel to the
fracture
Classification based on Plates
Interplate Earthquake - related to earthquake
occurring between the plate - Assam Earthquake
1987
Intraplate Earthquake - related to earthquake
occurring within the plate - Lattur Earthquake 1993
19/09/2020 11:30:00 ST2102 ASEISMIC DESIGN OF STRUCTURES 30
VARIOUS THEORIES
Fault
Strike-slip fault Dip-slip fault Oblique-slip fault
Normal fault Reverse or Thrust fault
19/09/2020 11:30:38 ST2102 ASEISMIC DESIGN OF STRUCTURES 31
VARIOUS THEORIES
Strike-Slip Fault
Strike-slip faults are the fractures where the blocks
move horizontally
19/09/2020 11:31:57 ST2102 ASEISMIC DESIGN OF STRUCTURES 32
VARIOUS THEORIES
Dip-Slip Fault
Dip-slip faults are inclined fractures - shifting vertical
19/09/2020 11:32:41 ST2102 ASEISMIC DESIGN OF STRUCTURES 33
VARIOUS THEORIES
Normal Fault
If the rock mass above an inclined fault moves down,
the fault is termed normal fault
19/09/2020 11:33:21 ST2102 ASEISMIC DESIGN OF STRUCTURES 34
VARIOUS THEORIES
Reverse or Thrust Fault
If the rock above the fault moves up, the fault is
termed reverse fault
19/09/2020 11:33:30 ST2102 ASEISMIC DESIGN OF STRUCTURES 35
VARIOUS THEORIES
Oblique Slip Fault
These fault have both a vertical and horizontal
component of motion along the fault
Combination of strike-slip and dip-slip motion
19/09/2020 11:33:57 ST2102 ASEISMIC DESIGN OF STRUCTURES 36
VARIOUS THEORIES
Seismic Waves
The release of large strain energy during an
earthquake travels in the form of seismic waves
19/09/2020 11:35:05 ST2102 ASEISMIC DESIGN OF STRUCTURES 37
VARIOUS THEORIES
Seismic
waves
Surface
Body waves
waves
Rayleigh
P-waves S-waves Love waves
waves
SV-waves SH-waves
19/09/2020 11:35:05 ST2102 ASEISMIC DESIGN OF STRUCTURES 38
VARIOUS THEORIES
Body waves Surface waves
Propagation is limited to a
Propagation of wave in all
volume of rock within a
direction and to all depth
few seismic wavelength
19/09/2020 11:35:44 ST2102 ASEISMIC DESIGN OF STRUCTURES 39
VARIOUS THEORIES
Body waves
Type P-waves S-waves
Nature of wave Compression waves Shear waves
Perpendicular to the
Along the direction
direction of
Particle motion of propagation of the
propagation of the
waves
waves
Volume change in
Instantaneous Not instantaneous
material
Shape change in
Not instantaneous Instantaneous
Material
19/09/2020 11:36:15 ST2102 ASEISMIC DESIGN OF STRUCTURES 40
VARIOUS THEORIES
19/09/2020 11:36:46 ST2102 ASEISMIC DESIGN OF STRUCTURES 41
VARIOUS THEORIES
Surface waves
Rayleigh
Type Love waves
waves
Horizontal motion
Elliptical motion with
Nature of ground that is transverse or
no transverse or
shaking perpendicular to the
perpendicular motion
direction of the wave
19/09/2020 11:37:45 ST2102 ASEISMIC DESIGN OF STRUCTURES 42
VARIOUS THEORIES
19/09/2020 11:39:23 ST2102 ASEISMIC DESIGN OF STRUCTURES 43
VARIOUS THEORIES
19/09/2020 11:39:55 ST2102 ASEISMIC DESIGN OF STRUCTURES 44
VARIOUS THEORIES
Basic Terminology
Hypocentre(Focus)
The hypocenter is the point within the earth where an
earthquake rupture starts
Epicentre
The epicentre is the point directly above it at the surface
of the Earth
19/09/2020 11:40:38 ST2102 ASEISMIC DESIGN OF STRUCTURES 45
VARIOUS THEORIES
Basic Terminology
Focal Depth
The distance between the epicenter and focus
Epicentral Distance
The distance from epicentre to any point of interest
19/09/2020 11:41:07 ST2102 ASEISMIC DESIGN OF STRUCTURES 46
VARIOUS THEORIES
Basic Terminology
Foreshock
Foreshocks are relatively smaller earthquakes that precede the
largest earthquake in a series, which is termed the mainshock.
Not all mainshocks have foreshocks.
Mainshock
The mainshock is the largest earthquake in a sequence,
sometimes preceded by one or more foreshocks, and almost always
followed by many aftershocks.
After shocks
An earthquake that follows a larger earthquake or main shock
and originates at or near the focus of the larger earthquake.
Generally, major earthquakes are followed by a larger number
of aftershocks, decreasing in frequency with time.
19/09/2020 11:42:03 ST2102 ASEISMIC DESIGN OF STRUCTURES 47
VARIOUS THEORIES
Time Magnitude Latitude Longitude Depth Designation
00:59:06 M=1.7 36.939 -121.679 8 Foreshock
01:00:55 M=3.3 36.246 -120.821 8 Main shock
01:06:02 M=2.9 36.244 -120.829 8 Aftershock
19/09/2020 11:42:11 ST2102 ASEISMIC DESIGN OF STRUCTURES 48
VARIOUS THEORIES
Salmas, Iran (Persia)
38.15N 44.70E
60 villages destroyed Death 2500
Foreshock killed 25 people
The town of Dilman (population 18,000) was completely destroyed,
but there were only 1,100 deaths because a magnitude 5.4
foreshock
Saved thousands of lives since many people choose to sleep
outdoors that night
Mainshock Magnitude 7.2
19/09/2020 11:44:02 ST2102 ASEISMIC DESIGN OF STRUCTURES 49
VARIOUS THEORIES
Seismicity of World
Distribution of
epicentres of
30000 earthquake
occurred during
1961-1967
19/09/2020 11:44:39 ST2102 ASEISMIC DESIGN OF STRUCTURES 50
VARIOUS THEORIES
Seismicity in India
Seismicity map in India
(From IS:1893 (Part 1): 2002)
19/09/2020 11:45:24 ST2102 ASEISMIC DESIGN OF STRUCTURES 51
MEASUREMENT SCALE
Magnitude
Magnitude is an measure of the amount of strain
energy released during an earthquake
Magnitude - single number for an particular
earthquake
19/09/2020 11:46:13 ST2102 ASEISMIC DESIGN OF STRUCTURES 52
VARIOUS THEORIES
Richter
Magnitude
Surface Wave
Magnitude
Body Wave
Magnitude
Magnitude
Duration
Magnitude
Moment
Magnitude
19/09/2020 11:46:38 ST2102 ASEISMIC DESIGN OF STRUCTURES 53
MEASUREMENT SCALE
Richter Magnitude
The Richter Magnitude for an maximum amplitude of
A µm at a point 100 km from epicenter
Richter scale is a logarithmic scale, (i,e) an
magnitude of 4 cause 10 times as much ground
movement as one of magnitude 3 and 100 times as much
as one of magnitude 2
19/09/2020 11:46:55 ST2102 ASEISMIC DESIGN OF STRUCTURES 54
MEASUREMENT SCALE
Intensity
Intensity is scale to measure the effect of earthquake
at different site
Intensity measurement based on the
•Effects of earthquake on living and non-living thing
•Acuity of the observer
19/09/2020 11:47:13 ST2102 ASEISMIC DESIGN OF STRUCTURES 55
MEASUREMENT SCALE
EXCEPTION while Measuring Intensity ??
Building on filled(Loose soil)
ground respond differently to the
earthquake vibration
19/09/2020 11:49:08 ST2102 ASEISMIC DESIGN OF STRUCTURES 56
MEASURMENT SCALE
Intensity
Twelve Point Modified
Ten Point Rossi Forrel Scale
Mercalli Scale
19/09/2020 11:50:11 ST2102 ASEISMIC DESIGN OF STRUCTURES 57
MEASUREMENT SCALE
In context to IS
1893 (Part I ):2002
Annex D
Page No:33
(Simplified form)
19/09/2020 11:50:17 ST2102 ASEISMIC DESIGN OF STRUCTURES 58
MEASUREMENT SCALE
Magnitude Intensity
Measure of strength of shaking
Measure of energy released at the
produced by the earthquake at a
source of the earthquake
certain location
Single number which does not vary Different location experience
from place to place different level of intensity
It is determined from the effect on
It is measured from seismographs people, structure and the natural
environment
19/09/2020 11:50:25 ST2102 ASEISMIC DESIGN OF STRUCTURES 59
MEASUREMENT SCALE
Example:
Bhuj Earthquake January 2001
Magnitude 7.7
Earthquake felt in Bhuj, Ahmedabad, Anjar and
Gandhidham
Magnitude is same in all the places
Intensity of Bhuj is different from the intensity at
Ahmedabad
19/09/2020 11:51:03 ST2102 ASEISMIC DESIGN OF STRUCTURES 60
MEASUREMENT SCALE
Isoseismal Line or Isoseists
A line on a map joining points of equal intensity for a
particular earthquake
Isoseismal line for Bhuj Earthquake January 2001
19/09/2020 11:51:46 ST2102 ASEISMIC DESIGN OF STRUCTURES 61
VIBRATION MEASURING INSTRUMENT
Seismograph
Seismograph is a instrument used for recording the
motion of earth surface caused by seismic wave as a function
of time
Seismogram - frequency and amplitude of shock wave
Modern Seismograph
◼Clock - record precise arrival time of specific seismic
wave
◼Sensor - measure the intensity of shaking
◼Recorder - tracing
◼Electronic amplifier and Data recorder - to store the
information
19/09/2020 11:52:19 ST2102 ASEISMIC DESIGN OF STRUCTURES 62
VIBRATION MEASURING INSTRUMENT
19/09/2020 11:53:05 ST2102 ASEISMIC DESIGN OF STRUCTURES 63
VIBRATION MEASURING INSTRUMENT
Basic construction of Seismograph
To measure horizontal motion - the inertial mass is
suspended on a hinge
To measure vertical motion - the inertial mass hangs
from the support by a spring
Recording device registers seismic vibration with a
pen attached to the inertial mass and the roll of paper
moves along with earth vibration
19/09/2020 11:53:50 ST2102 ASEISMIC DESIGN OF STRUCTURES 64
VIBRATION MEASURING INSTRUMENT
19/09/2020 11:54:02 ST2102 ASEISMIC DESIGN OF STRUCTURES 65
VIBRATION MEASURING INSTRUMENT
Instrument sensitive to high frequency seismic wave -
short period seismographs - record local earthquake
Instrument sensitive to low frequency seismic wave -
long period seismographs - record distant earthquake
Modern seismograph perform both the function
Earthquake - three directional movement - recorded
for three perpendicular direction - hence three sensor
(North South, East West, Vertical) direction
19/09/2020 11:54:39 ST2102 ASEISMIC DESIGN OF STRUCTURES 66
VIBRATION MEASURING INSTRUMENT
Seismogram
Seismogram are the record produced by seismographs
used to calculate the location and magnitude of an
earthquake
19/09/2020 11:55:24 ST2102 ASEISMIC DESIGN OF STRUCTURES 67
VIBRATION MEASURING INSTRUMENT
Strong Ground Motion
19/09/2020 11:56:53 ST2102 ASEISMIC DESIGN OF STRUCTURES 68
VIBRATION MEASURING INSTRUMENT
19/09/2020 11:56:54 ST2102 ASEISMIC DESIGN OF STRUCTURES 69
PAST EARTHQUAKE IN INDIA AND
WORLD
Himalayan Region
Magnitude/
S.No Name Location Year Death
Intensity
1. Kashmir Earthquake Srinagar 1885 - 3000
2. Shillong Earthquake Shillong 1897 8.7 1600
3. Kangra Earthquake Kangara 1905 8.5 20000
Bihar-Nepal border
4. Bihar-Nepal Earthquake 1934 8.3 10000
region
5. Assam Earthquake Assam 1950 8.5 1526
Bihar-Nepal border
6. Bihar-Nepal Earthquake 1988 6.5 1000
region
7. Indo-Burma Earthquake India-Burma border 1988 7.3 -
8. Uttarkashi Earthquake Uttarkashi 1991 7.0 768
9. Chamoli Earthquake Chamoli 1999 6.8 103
19/09/2020 11:56:54 ST2102 ASEISMIC DESIGN OF STRUCTURES 70
PAST EARTHQUAKE IN INDIA AND
WORLD
Andaman Nicobar
Andaman-Nicobar Andaman-Nicobar
1. 1941 8.1 -
Earthquake trench
Kutch Region
1. Samaji Earthquake Samaji 1668 X -
2. Kutch Earthquake Kutch 1819 8.0 2000
3. Anjar Earthquake Anjar 1956 6.1 115
4. Bhuj Earthquake Bhuj 2001 6.9 20000
Peninsular India
1. Bombay-Surat Earthquake Bombay-Surat 1856 VII -
2. Son Valley Earthquake Son Valley 1927 6.5 -
3. Satpura Earthquake Satpura 1938 6.3 -
4. Balaghat Earthquake Balaghat 1957 5.5
19/09/2020 11:57:05 ST2102 ASEISMIC DESIGN OF STRUCTURES 71
PAST EARTHQUAKE IN INDIA AND
WORLD
5. Koyna Earthquake Koyna 1967 6.0 177
6. Ongole Earthquake Ongole 1967 5.4 -
7. Broach Earthquake Bronch 1970 5.4 26
8. Latur Earthquake Latur 1993 6.2 10000
9. Jabalpur Earthquake Jabalpur 1997 6.0 54
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 72
PAST EARTHQUAKE IN INDIA AND
WORLD
Earthquake in World
Magnitude/
S.No Name Year
Intensity
1. Chile 1992 8.3
2. Japan 1933 8.5
3. India-China 1950 8.6
4. Alaska 1964 8.4
5. Sumatra 2004 9
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 73
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
As per Indian Meteorological Department , New Delhi
Magnitude : 6.9
Epicenter : Bhachau
Focal Depth : 25 km
Date : January 26, 2001, Friday
Radius of fault area : 23 km
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 74
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Indian plate is pushing against the Eurasian plate creating a
compression zone.
Gujarat area experiences similar compression due to plate
tectonics
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 75
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
The Bhuj earthquake
occurred on a
Reverse Thrust fault
Past Earthquake
Rann on Kutch, 1819, Mw=7.8, 3200 killed
Rann of Kutch, 1845, M=6.3
North of Anjar, 1956, Mw=6.3, 156 killed
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 76
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
▪Peak horizontal acceleration
of 0.11g
▪P waves (gentle motion) for
first 30 sec
▪S waves (strong and
damaging motion) for next
30 sec
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 77
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
FAILURE OF RC BUILDING
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 78
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Soft Storey Failure
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 79
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Soft Storey
In context to IS 1893 (Part I
):2002
Page No: 21
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 80
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Soft Storey
In context to IS 1893 (Part I
):2002
Page No: 27
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 81
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Floating Column
Failure
Soft Storey
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 82
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Vertical Geometric
Irregularity
In context to IS 1893 (Part I
):2002
Page No: 27
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 83
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Effect of Neglecting infill wall is
analysis?
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 84
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Plan and Mass Irregularity
In context to IS 1893 (Part I
):2002
Page No: 10
Static
Eccentricity
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 85
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Plan Irregularity Mass Irregularity
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 86
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 87
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Short Column
Poor Quality of
Construction
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 88
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Damage to Structural
Elements
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 89
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Transverse Reinforcement
In context to IS 13920 : 1993 Page No: 6,7
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 90
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Damage to Infill Walls
How the infill wall fail?
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 91
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Damage to Water
Tank
Torsion of 500mm
Why?
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 92
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Damage to
Staircase
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 93
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Damage to
Staircase
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 94
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Damage to Elevators
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 95
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Inconsistent Seismic Performance of Building
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 96
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
How to Study this effect in Software?
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 97
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
FAILURE OF MASONRY BUILDING
19/09/2020 11:09:14 ST2102 ASEISMIC DESIGN OF STRUCTURES 98
PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Typical
features of
damages in
masonry
building
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PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
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PAST EARTHQUAKE IN INDIA AND
WORLD
-BHUJ EARTHQUAKE
Effect of Earthquake
on Code Designed
Structures
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PAST EARTHQUAKE IN INDIA AND
WORLD
Lesson Learnt
Design should be based on IS 1893 (Part 1):2002 and
IS 13920:1993
Building with vertical and mass irregularity -
Dynamic analysis and Inelastic design
Strong column and weak beam
Infill wall - incorporated in structural analysis
Shear wall - increasing stiffness - uniformly
distributed in both principle direction
Quality of construction
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PAST EARTHQUAKE IN INDIA AND
WORLD
Lesson Learnt – Inelastic Design
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PAST EARTHQUAKE IN INDIA AND
WORLD
Lesson Learnt - Strong column and weak beam
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PAST EARTHQUAKE IN INDIA AND
WORLD
Lesson Learnt - Infill Wall
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PAST EARTHQUAKE IN INDIA AND
WORLD
Lesson Learnt - Shear Wall
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PAST EARTHQUAKE IN INDIA AND
WORLD
Is it possible to predict the damage in structure before
earthquake?
Sikkim Earthquake September 18,2011
Column
Shear
Pushover Analysis
Showing Hinge
Result
Y. Singh & Phani Gade
Department of Earthquake Engineering, Indian Institute of Technology Roorkee, India
D.H. Lang & E. Erduran
NORSAR, International Centre of Geohazards (ICG), Kjeller, Norway
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RESPONSE SPECTRUM
Important Definition
In context to IS 1893 (Part I ):2002
Page No: 10
ZPA(Zero Period Acceleration): Zero period
acceleration implies the maximum acceleration
experienced by a structure having zero period ( T=0)
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RESPONSE SPECTRUM
Important Definition
For what kind of Structure T=0?
T1<T2<T3<T4
Infinitely rigid structure; Deformation is zero
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RESPONSE SPECTRUM
Response Spectrum
The representation of the maximum
response(Acceleration, Velocity, Displacement) of
idealized SDOF system having certain period and
damping during earthquake ground motion
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RESPONSE SPECTRUM
Equation of Motion for SDOF
Free Body
Diagram
By applying Newton Second
Law
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RESPONSE SPECTRUM
Example
El Centro ground motion
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RESPONSE SPECTRUM
The time variation u(t)
for an damping of 2
percent SDOF system with
Tn= 0.5 sec, 1 sec, 2 sec
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RESPONSE SPECTRUM
Displacement Response
for an damping of 2 percent
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RESPONSE SPECTRUM
Pseudo-Velocity
Response for an damping of
2 percent
Strain Energy Stored in
the system during
earthquake
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RESPONSE SPECTRUM
Pseudo-Accelerati
on Response for an
damping of 2 percent
Peak value of Base
Shear
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RESPONSE SPECTRUM
How to Read an Earthquake Data?
http://peer.berkeley.edu/smcat/search.html
Chi Chi Earthquake
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RESPONSE SPECTRUM
Construction of Response Spectrum
1.Define the ground acceleration; typically the ground motion
ordinates for every 0.02 Sec or 0.005 Sec or 0.1 Sec
2.Select the natural vibration period and damping ratio of a
SDF system
3.Compute the deformation of this SDF system due to the
ground motion (Using Numerical Method)
4.Determine u(0) the peak value of u(t)
5.The spectral ordintes are D=u(0), pseudo-velocity and
pseudo-acceleration
6.Repeat step 2 to 5 for a range of natural vibration period and
damping ratio
7.Present the result graphically
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RESPONSE SPECTRUM
Computing Deformation – Numerical Method
1.Method on Interpolation of Excitation
2.Central Difference Method
3.Newmark Method
i.Average Acceleration Method
ii.Linear Acceleration Method
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RESPONSE SPECTRUM
Example - Method on Interpolation of Excitation
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RESPONSE SPECTRUM
Example - Method on Interpolation of Excitation
Problem in Dynamics of
structures by Anil K.
Chopra
Third Edition
Page No: 205
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RESPONSE SPECTRUM
Example - Method on Interpolation of Excitation
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RESPONSE SPECTRUM
Combined D-V-A Spectrum
Combained D-V-A
response spectrum for
El Centro ground
motion for an
damping percentage
of 0, 2, 5, 10 and 20%
For what this use of this
graph???
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RESPONSE SPECTRUM
Combined D-V-A Spectrum
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RESPONSE SPECTRUM
Combined D-V-A Spectrum
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RESPONSE SPECTRUM
How the Code Response Spectrum is obtained??
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RESPONSE SPECTRUM
Normalization of earthquake response spectra
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RESPONSE SPECTRUM
Example - Spectrum Compatible Time History
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RESPONSE SPECTRUM
Example - Spectrum Compatible Time History
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RESPONSE SPECTRUM
Example - Spectrum Compatible Time History
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RESPONSE SPECTRUM
Significant and Uses
Convenient and practical way to find the acceleration, velocity
or displacement
Practical way to apply the knowledge of structural dynamics
to determine the lateral force and to design of structures
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