This document discusses various aspects of earthquake-resistant structures. It begins by listing different types of natural disasters and their impacts. It then covers primary and secondary effects of earthquakes, as well as causes of earthquakes. Different classifications of earthquakes are presented. The effects of earthquakes on vertical and horizontal structures are described. Concepts in earthquake-resistant design like strong-motion zones are introduced. Seismic zoning maps of India are shown. Architectural guidelines for earthquake-resistant construction focus on regular building geometry and arrangements of columns. Structural aspects address issues like soft stories, large cantilevers, resonance, head weight, stiffness irregularity, strong-column weak-beam design, and discontinuities. The document emphasizes the

1. Earthquake
Resistant Structures
NAME- NITTIN BHAGAT
ROLL NO. – 19EEACE040
TO- MR. DHARMENDRA SINGH DHAKA

2. Natural Disasters
Tornado, Cyclone
Earthquake
Floods Fire

3. Natural Disasters
Volcano
Hurricane

4. Loss of Human Life in Disasters
55%
Floods
Earthquake
Valcanos
Other
Hurricane
3%
2%
10%
30%

5. Effect of Earthquake
Primary Effects
Ground Break, Fault
formation
Secondary Effects
Failure of R. C. & steel Structures
Failure of masonry Structures
Failure of railway, highway & bridges
Land slides, Liquefaction & site effects
Failure of geotechnical structures
Tsunami

6. Causes for Earthquake
• Tectonic earthquake
• Volcanic earthquake
• Rock fall or collapse of cavity
• Microseism
• Explosion (Controlled blast)
• Reservoir induced earthquake
• Mining induced earthquake
• Cultural Noise (Industry, Traffic etc.)

7. Classification of Earthquakes
Based on focal depth
Based on magnitude
Based on source

8. Period of Vibration
Building at Rest Ground Accelerates to Left
Ground Accelerates to Right Ground & Building at Rest

9. Effects of Earthquake on Vertical Structures
Repeated actions of earthquake
results in loss of resistance to rocking effects

10. Principal modes of Failure of Shear wall
Sliding Rocking Bending

11. Failure of Shear wall
Failure of one of
the shear walls in
the building at the
construction joints
due to poor
workmanship at
the joints. And it
was attributed to
lack of adequate
axial-flexural
capacity .

12. Inertia due to earthquake

13. Earthquake effects on Buildings
U-D
EW
Movement of
building
Direction of
forces on
Building
NS

14. Earthquake effects on Buildings
Vertical Acceleration – Significant near epicenter
(Adds to /Reduces the gravity forces, Large balconies)
Horizontal Acceleration – produces sway
(Effect of Inertia, distribution of lateral forces)
Effect of Resonance - Excessive deflection
(Natural frequency coincides with Earthquake frequency)
Ymax
w /w
eq nat
0 1 2

15. Modes of Vibration due to Earthquake Forces

16. Effects of Earthquake on Stress Distribution

17. Effects of Earthquakes on Stress distribution
Change in Stress
Change in Moment
Change in Load

19. Gravity resisting House Elements
Roof Joists
Walls
Floor Beams
Foundations

20. Horizontal Force resisting House Elements
Roof Diaphragm
Shear Wall
f
1
f
2
f
3
Foundation
Floor
Diaphragm

21. Earthquake Resistant Design Concept
S t ro n g M o tio n Z o n e
Level 1 Maximum Credible Earthquake (MCE)
500 Years Return Period
2 % Possibility of occurrence in 50 Yrs
Level 2 Design Basis Earthquake (DBE)
250 Years Return Period
10 % Possibility of occurrence in 50 Yrs

22. Earthquake Resistant Design
Philosophy
Building
should resist minor earthquakes (<DBE)
with some non-structural damage
should resist moderate earthquake (DBE)
with some structural damage, but without
failure
can fail at most severe earthquake (MCE),
but with sufficient warning.

23. SEISMIC ZONE
MAP OF INDIA
F=m *a
a = Z*g
Z = Zone Factor
m
F

24. Architectural Aspects
of Earthquake Resistant
Construction

25. Regular and Irregular Configurations
To perform well in an earthquake, a building should
possess four main attributes:
Simple and regular configuration
Adequate lateral strength
Stiffness
Ductility
Buildings having simple regular geometry and uniformly
distributed mass and stiffness in plan as well as in
elevation, suffer much less damage than buildings with
irregular configurations.
Buildings with plan irregularity suffer from torsional modes
of vibration whose effects may not be adequately
represented in the equivalent static seismic coefficient
method.

26. IRREGULAR BUILDINGS
Torsional Irregularity
Plan Irregularity- Re-entrant Corners
Out-of-Plane Offsets
Stiffness Irregularity
Mass Irregularity
Vertical Geometry Irregularity
Discontinuity in Capacity – Weak Storey

27. Guidelines for Planning
Geometry of buildings
Symmetric Plans
Symmetric Elevations

28. Guidelines for Planning
Geometry of buildings
Un-symmetrical Plans
Un-symmetrical Elevations

29. Guidelines for Planning
Desirable geometry of buildings
L< 3B < 0.2B
B
B
Separation
PLANS
< 0.25 B
< 0.15 B
H<4B
B B
ELEVATIONS

35. Guidelines for Planning
Arrangement of Columns
Good arrangement of columns Poor arrangement of columns

36. Guidelines for Planning
Rotation about the axis
Y
Building is strong about
YY axis and weak
About XX axis
x x
Y
Provide columns
to make
x x
it strong about XX axis
Y

37. Guidelines for Planning
Lateral load Resisting system
L
Provide cross
Wall to increase
stiffness
B
B
Columns
Walls
Clear spacing < 40 times thickness of wall
( L and B < 7 m )

38. Lateral force resistant systems
Rigid Frame
Simply supported System
Shear wall System
Bracing system

39. Lateral force resistant system- Braced System
Bracing system

40. Earthquake Resistant Construction – Bad Geometry

41. Torsion of unsymmetrical Plans
Center of lateral resistant /stiffness center
Resisting force
CG. Of Building mass
Applied force
Lateral bracing
Direction of Ground Motion

42. Improper
Proper
Earthquake Resistant construction

43. General Guidelines for Planning
Building and its Structure Should
Have a Uniform and Continuous
Distribution of Mass, Stiffness,
Strength and Ductility

44. Structural Aspects of
Earthquake Resistant Design

45. Structural Aspects
Soft storey Mechanism
Third floor
second floor
Shear wall
First floor
Basement

46. Soft Storey

48. Soft Storey Collapse

49. Soft Storey Collapse, Bhuj 2001

50. Large Span Cantilevers
Up/Down
Acceleration

51. Large Span Cantilevers
Up/Down
Acceleration

52. Avoid Resonance
Natural frequency
&
Its Importance

53. Tacoma Narrows bridge (1940)
Western Washington State, Pacific Northwest
Before Collapse After Collapse
Wind provided an external periodic frequency that matched the
natural frequency of 853 m long Suspension Bridge

54. Avoid Head Weight
SA- 7, Head Weight, Bhuj 2001

55. Head Weight
Krishna
Apartments,
Airport Road,
Bhuj

56. Stiffness Irregularity

57. Stress
concentration
& change in
the stiffness

58. Structural Aspects
Strong column and weak beams
Good – Failure in beams Poor– Failure in Columns

59. Strong Column & Weak Beam Concept

60. Structural Aspects
Weak column
and strong beams

61. Avoid Short Column

62. Failure of Express highway in Kobe

63. Short column failure
due to insufficient
transverse
reinforcement
Krishna Apartments,
Airport Road, Bhuj

64. Crushing of corner
column – Insufficient
reinforcement :
Tera Nam Mandir, Bhuj

65. Structural aspects
Redundancy in Building
Rigid
Connection
Simple
Connection
Two load paths
One load path
Columns
Walls

66. No Pounding
?
Maintain a good distance Between adjacent tall
Buildings to avoid Collision during oscillation

67. Whip Effect
of Apartment
Bhuj 2001

68. Weak Link
Stair case or
Lift well

69. Weak Link, Bhuj 2001

70. Weak Link, Bhuj 2001
No lateral load force transfer mechanism to the core
Punjal Apartments, Ahmedabad

71. Himagiri
Apartment
weak link

72. Failure of Pre cast components in a
building due to inadequate connection

73. Loss of Support
Simple Supports

74. Structural aspects
Column Beam connection
Movement of supports due to horizontal force

75. Bad construction practice of casting the ground floor
columns up to the bottom of the beam and leaving a gap
Shri Hari Niwas Building, Main Road, Bhuj

76. Weak joint
Bhuj 2001

77. Discontinuity of
the longitudinal
reinforcement
Bombay Dying
Market, Station
Road, Bhuj

78. Poor quality materials
and workmanship
Neelima Park Apartments,
Ahmedabad

79. Perfect Apartment- no failure, Bhuj 2001

80. For you to conclude
Does the earthquake kill people or the engineers
/ architects or buildings are responsible for it?
Will a well engineered structure behave better?
Is it necessary to build all structures at all
locations to be earthquake proof to same
degree?
If so, what magnitude of earthquake should they
counter?

81. Six main focus areas
1. Awareness and Preparedness
2. Response
3. Education, Training, Capacity-Building,
Research & Development, and
Documentation
4. Regulation and Enforcement
5. Earthquake-Resistant Construction of
New Structures
6. Selective Seismic Retrofitting of
Existing Critical and Lifeline Structures

82. Conclusions
Earthquake risk arises mainly due to unsafe
constructions. For meaningful earthquake risk
mitigation, the country has to embark on two initiatives
in a pre-decided time frame:
First to ensure that all new constructions must have
earthquake resisting measures and
Second, the critically important existing buildings
should be identified, assessed and retrofitted as
found necessary.
Establishment of techno-legal and techno-financial
regimes.
Capacity building of architects, engineers and masons