1. Er. P. K. Tripathy, MIE , Dy. Executive Engineer(Civil)
Earthquake Resistant Building Design , Construction Detailing and Measures by
Er. P. K. Tripathy, MIE , Dy. Executive Engineer(Civil)

2. BASIC SEISMOLOGY Inner core of earth is solid of radius of 1290 km.
Heavy metals like nickel and iron
Temperature is 25000C ,4 million atm., density~13.5gm/cc ) .
Outer core is liquid having thickness of 2200 km.
Mantle is viscous fluid 2900 km .
Crust is about 5 – 40 km thick consists of Light materials like Basalt & granites of temp~250C, 1atm., density~1.5gm/cc .

3. BASIC SEISMOLOGY
Plate Tactonics: The convective flows of mantle materials cause the crust and some portion of the mantle to slide on the hot molten outer core.
The sliding of earth’s mass takes place in pieces called Tectonic Plates. The surface of earth consist of seven tectonic plates and many smaller ones( fig-2).
Figure 2:Major Tectonic Plates on the Earth’s Surface

4. BASIC SEISMOLOGY
These plates move in different directions. Some times plates collide , thereby forming mountains. Sometimes plates move away from one another forming rifts. Sometimes plates move side by side along same direction or opposite direction. These three types of interplate interactions are called convergent, divergent and transform boundaries (Fig-3).
Figure 3: Types of Inter-Plate Boundaries

5. BASIC SEISMOLOGY
Rocks are made of elastic materials and elastic strain energy stored in them during the deformation that occur due to gigantic tectonic plate actions that occur in earth. The material of rock is brittle.Thus the rocks along the weak region in the earth’s crust reach their strength, a sudden movement takes place opposite sides of fault and suddenly slip and release large elastic strain energy stored in the interface of rocks (fig-4)
Figure 4:Elastic Strain Build-up and Brittle Rupture

6. BASIC SEISMOLOGY
Tectonic features of India: India lies in the North Western end of Indo- Australian Plate which collides with Euracian Plate
3-Tectonic sub-regions of India are Himalyas , Plains of Ganges & other rivers and Peninsula.
Figure 5 : Tectonic Plate Boundaries at India

7. BASIC SEISMOLOGY Seismotectonic Units of India
Lithosphere of Earth’s crust consists of
(A) Oceans & (B) Continents
Ocean at plate boundary leads to subduction i.e.., movement into the mantle
Continent remains close to the surface due to buoyant resulting shortening and thickening like Himalayas & Tibet
Figure 6 : Continental crust and Ocean Crust

8. BASIC SEISMOLOGY
Focus is a point on the fault where slip starts. Epicenter is a point just above the focus on the ground.
Epicentral Distance is the distance of place of interest from epicenter on ground.
Most of the damaging earthquakes have shallow focus with focal depths less than about 70km.The earthquakes (of small sizes) occurring after the big earthquake (Main shock) are called Aftershocks.
Figure 7 : Basic Terminology

9. EARTHQUAKE: SEISMIC WAVES
Strain energy released due to movement of rocks in the fault plane generates seismic waves which moves in all directions and undergoes reflections & refractions at various elastic layer interfaces.
Seismic Waves: (A) Body waves
(B) Surface Waves
Body Waves (i) Primary waves (P-waves)
(ii) Secondary Waves (S-Waves)
Surface Waves: (i) Rayleigh waves
(ii) Loves Waves
Figure 8 : Motion Caused by waves
Figure 9 : Arrival of Seismic Waves

10. LIST OF SOME SIGNIFICANT EARTHQUAKES IN INDIA AND ITS NEIGHBOURHOOD
SL NO.
DATE
EPICENTRE
LOCATION
MAGNITUDE
Lat (Deg.N)
Lat (Deg.E) 1.
1819 JUN 16 
23.6
68.6
KUTCH,GUJARAT
8.0 2.
1869 JAN 10 25 93
NEAR CACHAR, ASSAM
7.5 3.
1885 MAY 30
34.1
74.6
SOPOR, J&K
7.0 4.
1897 JUN 12 26 91
SHILLONG PLATEAU
8.7 5.
1905 APR 04
32.3
76.3
KANGRA, H.P 6.
1918 JUL 08
24.5
91.0
SRIMANGAL, ASSAM
7.6 7.
1930 JUL 02
25.8
90.2
DHUBRI, ASSAM
7.1 8.
1934 JAN 15
26.6
86.8
BIHAR-NEPALBORDER
8.3 9.
1941 JUN 26
12.4
92.5
ANDAMAN ISLANDS
8.1
10.
1943 OCT 23
26.8
94.0
ASSAM
7.2
11.
1950 AUG 15
28.5
96.7
ARUNACHAL PRADESH-CHINA BORDER
8.5
12.
1956 JUL 21
23.3
70.0
ANJAR, GUJARAT
13.
1967 DEC 10
17.37
73.75
KOYNA, MAHARASHTRA
6.5
14.
1975 JAN 19
32.38
78.49
KINNAUR, HP
6.2
15.
1988 AUG 06
25.13
95.15
MANIPUR-MYANMAR BORDER
6.6
16.
1988 AUG 21
26.72
86.63
BIHAR-NEPAL BORDER
6.4
17.
1993
18.08
76.52°
LATUR
18.
2001 JAN 26
23.41°N,
70.23°E
BHUJ , GUJARAT
19.
2015 APR 25
28.147°N
84.708°E
NEPAL
7.8

11. Seismic Zones in India Zone-II(Zone-I merged with Zone-II) Zone-III
Zone-IV
Zone-V
Figure 10 : Seismic Zones in India

12. Heaps of rubble after the Bihar Earthquake in 1934
Magnitude - 8.7
Epicenter - 25°N, 85°E (240 km away from Kathmandu)
Heaps of rubble after the Bihar Earthquake in 1934

13. Fig- 12 :Destroyed building after the Latur earthquake
Magnitude - 6.4
Epicenter °N, 76.52°E
Fig- 12 :Destroyed building after the Latur earthquake

14. Damages in the Earthquake
Bhuj Earthquake of January 26, 2001
Magnitude 7.7
Epicenter °N, 70.23°E
Damages in the Earthquake

15. Damages in the Earthquake
Chile Earthquake of 2010
Magnitude 8.1
Damages in the Earthquake

16. Nepal Earthquake of April 25, 2015
Magnitude 7.8
Epicenter °N °E 

17. Nepal Earthquake of April 25, 2015
Magnitude 7.8
Epicenter °N °E 

18. Nepal Earthquake of April 25, 2015
Magnitude 7.8
Epicenter °N °E 

19. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS
Improper Planning and Design of Buildings :
Pounding Damage of Adjacent Buildings:
Soft-Ground Storey:
Softness of Base Soil :
Bad Structural System:
Heavy Water Tanks on the Roof :
Improper Detailing of Reinforcement:
Short Column Detailing:
Torsional Failures:
Lack of Stability of Infill Walls:
Poor Construction Quality:

20. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS :-
IMPROPER PLANNING AND DESIGN
The behaviour of a building during earthquakes depends on its shape, size and geometry and how the earthquake forces carried to the ground.
Large torsional responses can be expected in the buildings having large eccentricity and low torsional stiffness.
The torsional moment is induced in the building by earthquake forces due to eccentricity between the centre of mass and centre of rigidity of the building.
Seismic torsional response has always a principal cause of structural failure in every major earthquake
Hence, at the planning stage itself, architects and structural engineers must work together to ensure that the unfavourable features are avoided and a good building configuration is chosen.

21. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS : -
IMPROPER PLANNING AND DESIGN
The importance of the configuration of a building was aptly summarised by Late Henry Degenkolb, a noted Earthquake Engineer of USA, as:
“If we have a poor configuration to start with, all the engineer can do is to provide a band-aid - improve a basically poor solution as best as he can. Conversely, if we start-off with a good configuration and reasonable framing system, even a poor engineer cannot harm its ultimate performance too much.”

22. Importance of Building Form
THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS - IMPROPER PLANNING AND DESIGN
Importance of Building Form
The centre of mass coincides with the centre of rigidity of the building.
The net resisting force balances the earthquake induced inertia force thereby eliminating the torsional effects.
Fig-11: Plan of Symmetrical Building with Centres of Resistance and Mass Coinciding

23. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS : -
IMPROPER PLANNING AND DESIGN
A plan of unsymmetrical building is shown in Fig12(a).
There is an eccentricity between the net resistance and induced earthquake inertia force producing the torsional moment.
A building, which is symmetrical with respect to centre of mass and centre of rigidity in one direction and not symmetrical in other direction is shown in Fig 12 (b).
The net resistance along X-direction will have an eccentricity with the earthquake induced inertial force causing twist.
Fig 12 : (a) Centres of Resistance and mass not coinciding, (b) Centres of Resistance and mass coinciding

24. Some of the building forms.
THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS : -
IMPROPER PLANNING AND DESIGN
Fig 13 shows twisting of the building.
Some of the building forms.
Fig1 4: Re-entrant Corners

25. Collapse of Re-entrant corner of the “L” shaped Building
THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS : -
IMPROPER PLANNING AND DESIGN
Collapse of Re-entrant corner of the “L” shaped Building
in 1963 Macedonia EQ, Skopje

26. TIPS FOR SUITABLE CONFIGURATION
For eliminating the torsional moment due to earthquake, separation or seismic joints may be provided.
Fig 15: Separation and Seismic Joints in Buildings with Re-entrant corners

27. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS : -
IMPROPER PLANNING AND DESIGN
Fig 16: Simple Plan of Building do well during earthquake

28. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS : -
IMPROPER PLANNING AND DESIGN
Fig 17: Simple Plan of Building do not perform well during earthquake

29. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS : -
IMPROPER PLANNING AND DESIGN
Fig 17(a): Plan of Building do not perform well during earthquake

30. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS : -
IMPROPER PLANNING AND DESIGN
Fig 17(b): Plan of Building do not perform well during earthquake

31. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS : -
IMPROPER PLANNING AND DESIGN
Fig 17(c): Plan of Building do not perform well during earthquake

32. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS :- Pounding Damage of Adjacent Buildings
When two buildings are too close to each other, they may pound on each other during strong shaking. With increase in building height, this collision can be a greater problem. When building heights do not match the roof of the shorter building may pound at the mid-height of the column of the taller one; this can be very
Dangerous.
Fig 18: Pounding Damage during strong Shaking

33. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS :-
Soft-Ground Storey:
It is observed from the literature that many multi-storeyed RC buildings with open ground storey (stilt floor) damaged severely or collapsed due to earthquake as these buildings introduced severe irregularity of sudden change of stiffness between the ground storey and upper storeys.. The ‘soft’ storey is severely strained causing its total collapse, much smaller damages occurs in the upper storeys.
Fig 19: Soft – Ground Storey

34. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS :-
Soft-Ground Storey:

35. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS :-
Soft-Ground Storey:

36. (i) Amplification of the ground motion at the base of the building
THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS :- Softness of Base Soil :
The soft soil on which buildings to be founded will have affected the response of the buildings in three ways:
(i) Amplification of the ground motion at the base of the building
(ii) Absence of foundation raft or piles
(iii)Relative displacement between the individual column foundations vertically and laterally, in the absence of either the foundation struts as per IS: or the plinth beams
Damage due to differential settlement, Chi-Chi earthquake Taiwan (1999)
Tilting of apartment buildings, Niigata (1964)

37. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS :- Bad Structural System:
Floating columns used in structural systems are very undesirable in earthquake zones of moderate to high intensity as in Zone III, IV & V since it will induce large vertical earthquake forces even under horizontal earthquake ground motions due to overturning effects.
Fig 20: Sudden Deviation in Load transfer path in height lead to poor performance

38. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS :- Heavy Water Tanks on the Roof
Heavy water tanks add large lateral inertia forces on the building frames due to the so called ‘whipping’ effect under seismic vibrations, but remain unaccounted for in the design.

39. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS :- Improper Detailing of Reinforcement:
The detailing of the stirrups in the columns is to satisfy lateral shear requirements in the concrete of the joint as required under IS and IS: The shape and spacing of stirrups seen in mostly collapsed and severely damaged columns with buckled reinforcement were found to be non-conformity with the above codes. Further, it is also observed in the damaged buildings that the detailing of longitudinal reinforcement of beam-column joint is not satisfied with the codal provisions of IS: and IS:
Fig 21: Detailing of reinforcement at beam-column joint
(Beam bars should run straight through columns)

40. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS :
Short Column Detailing:
In some situations the column is surrounded by walls on both sides such as up to the window sills and then in the spandrel portion above the windows but it remains exposed in the height of the windows. Such a column behaves as a short column under lateral earthquake loading where the shear stresses become much higher than normal length columns and fail in shear

41. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS :
Short Column Detailing:

42. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS :
Short Column Detailing:

43. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS :
Short Column Detailing:

44. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS :
Torsional Failures:
Torsional failures are seen to occur where the symmetry is not planned in the location of the lateral structural elements as for example providing the lift cores at one end of the building or at one corner of the building or unsymmetrically planned buildings in L shape at the street corners. Large torsional shears are caused in the building columns causing there torsional shear failures.

45. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS :
Lack of Stability of Infill Walls:
If the infill walls are not properly attached either to the column or the top beams, the stability against out-of-plane bending under horizontal earthquake forces may be affected.
THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS :
Poor Construction Quality:
In the some of the damaged high rise buildings it is observed that the construction quality of the damaged R.C. buildings was found to be much below that desired, as seen by the cover to reinforcement in the damaged members and the bad quality of concrete in the columns in 150 to 300 mm length just below the floor beams and within the beam column joints.

46. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS : Poor Construction Quality

47. THE CAUSES OF THE COLLAPSE OF RC FRAME BUILDINGS : Poor Construction Quality

49. The basic criteria should be based on lateral strength
EARTHQUAKE DESIGN PHILOSOPHY
The basic criteria should be based on
lateral strength
deformability (serviceability)
ductility

50. IS:1893:2002”Criteria for earthquake resistant design of structures”
IS CODE OF PRACTICE FOR EARTHQUAKE RESISTANT DESIGN
IS:1893:2002”Criteria for earthquake resistant design of structures”
IS 13920: 1993, “Code of Practice for Ductile Detailing of Reinforced Concrete Structures Subjected to Seismic Forces”.
IS 4326: 1993, “Code of Practice for Earthquake Resistant Design and Construction of Buildings”.
IS:456:2000 ”Code of practice for plain and reinforced concrete”

51. LOAD COMBINATIONS FOR EARTHQUAKE RESISTANT DESIGN
Load Case DL LL
EQL 1
1.0
……..
……… 2 3 4
1.5
………. 5
1.2 6
-1.2 7 8
-1.5 9
0.9 10

52. EARTHQUAKE RESISTANT DESIGN

53. EARTHQUAKE RESISTANT DESIGN AND DETAILING IN BEAMS

54. EARTHQUAKE RESISTANT DESIGN AND DETAILING IN BEAMS

55. EARTHQUAKE RESISTANT DESIGN AND DETAILING IN BEAMS

56. EARTHQUAKE RESISTANT DESIGN AND DETAILING IN COLUMNS

57. Design and Detailing Procedure as per IS:13920-1993
Clause Provisions of this code shall be adopted in all reinforced concrete Structures which satisfy one of the following 4 conditions.
(i) The structure is located in seismic zone IV or V.
(ii) The structure is located in Seismic Zone III and has importance factor (I) greater than 1.0.
(iii) The structure is located in Seismic Zone III and is an industrial structure.
(iv) The structure is located in Seismic Zone III and is more than 5 storeys.
Clause 3.4 : Hoop- It is closed stirrup having a 135 degree hook with 10 diameter extension (but not less than 75 mm ) at each end that is embedded in the confined core of the section .
Clause 5.2 : For all buildings which are more than 3 storeys in height the minimum grade of concrete shall be M20.
Clause 5.3 : Steel reinforcement of grade Fe 415 or less only shall be used .
Clause 6: For flexural members
6.1.1 The factored axial stress on the member under earthquake loading shall not exceed 0.1 fck.
6.1.2 The member shall have a width to depth ratio of more than 0.3
6.1.3 Width of flexural member not less than 200 mm.
6.1.4 Depth if member not less than 0.25 of the clear span .

58. EARTHQUAKE RESISTANT DESIGN AND DETAILING IN COLUMNS

60. EARTHQUAKE RESISTANT DESIGN AND DETAILING IN COLUMNS

61. Design and Detailing Procedure as per IS:13920-1993
6.3.5 The spacing of hoops over a length of 2 d at either end of a beam shall not exceed.
a)d/4. and b) 8x dia of smallest bar ,But not less than 100 mm.
The first hoop shall be at a distance not exceeding 50 mm from the joint face. Vertical hoops at the same spacing as above shall also be provided over a length equal to 2 d on either side of a section where flexural yielding may occur under the effect of seismic forces . Elsewhere the beam shall have vertical hoops at a spacing not exceeding d/2.
Clause 7 Columns subjected to bending and axial load.
7.1.1 These requirement apply to columns which have factored axial force in excess of (0.1 fck) under the effect of earthquake forces.
7.1.2 The minimum dimension of column shall be 200 mm . However where in frames where beams have c/c span exceeding 5m, or column having unsupported length exceeds 4m the shortest dimension shall not be less than 300 mm.
7.1.3 The ratio of shortest dimension to the perpendicular dimension shall be preferably NOT less than 0.4.
Clause 7.2 Longitudinal Reinforcement
7.2.1 Lap splices shall be provided only in the central half of the member length.Itshould be proportioned as a tension splice .Hoops hall be provided over entire the splice length at spacing not exceeding 150 mm center to center .
Not more than 50 percent of bars shall be spliced at one section.
7.2.2 Any area of column that extends more than 100 mm beyond the confined core due to Architectural requirements shall be detailed in the matter .
In case of the contribution of the area to strength has been considered then it will have the minimum longitudinal and transverse reinforcement asper this code . However if this area has been treated as non structural the minimum reinforcement shall be governed by I.S. 456 provisions .

62. Clause 7.3 Transverse Reinforcement
7.3.2 The spacing of rectangular hoops shall not be more than 300 mm c/c .If the length of any
side of stirrup , exceeds 300 mm a cross tie shall be provided or a pair of overlapping hoops may be provided.
Clause 7.4 Special Confining Reinforcement
7.4.1 This shall be provided over a length of (lo) from each joint face towards mid span on either side of any section lo shall not be less than
(a) larger lateral dimension of the member . (b) 1/6 of clear span of member and (c) 450 mm.
7.4.2 When a column terminates in to a footing or mat special confining reinforcement shall extended at least 300 mm in to the footing or mat.
7.4.3 The spacing of hoops used as a special confining reinforcement shall not exceed ¼ of minimum member dimension but need not be less than 75 mm nor more than 100 mm.
7.4.4 The minimum area of cross section of bar forming circular hoops or spiral to be used as special confining reinforcement shall not be less than
Ash = .09 S Dk (fck/fy) [(Ag/Ak) -1.0]
Where
Ash = area of the bar cross section .
S = Pitch of spiral or spacing of hoops.
Dk = diameter of core measured to the outside of spiral or hoop .
Fck = characteristic compressive strength of concrete cube .
Fy = yield stress of (spiral/ hoop ) steel
Ag = gross area of column cross section .
Ak = area of concrete core should not exceed 300mm

63. Clause 8 Joints of frames
7.4.8 The area of cross section Ash of the bar forming rectangular hoop to be used as special confining reinforcement shall not be less than
Ash = 0.18 S.h. (fck/fy) [(Ag/Ak) -1.0]
Where
H = longer dimension of rectangular hoop.
Ak = Area of concrete core in the rectangular hoop measured to its outside dimensions.
Clause 8 Joints of frames
8.1 The special confining reinforcement as required at the end of column shall be provided through the joint is confined as specified by 8.2
8.2 A joint, which has beams framing in to all vertical faces of it and where each beam which is at least ¾ of the column width, may be provided with half the special confining reinforcement required at the end of column. The spacing of hoops shall not exceed 150 mm.

64. Ductile Detailing confirming to IS:13920

65. Design and Detailing Procedure as per IS:13920-1993
Clause 6.2 Longitudinal reinforcement : (a) At least two bars at top and two bars at bottom shall be provided through out the member length .
(b) The tension steel ratio on any fact at any section shall not be less than
Rho (min)= 0.24 [(square root of fck)/fy] .
6.2.2 The maximum steel ratio on any face at any section shall be not exceed Rho(max) =
6.2.3 The positive steel at joint face must be at least equal to half the negative steel at that face.
6.2.4 The steel provided at each of the top and bottom face of the member at any section along its length shall be at least equal to one fourth of the maximum negative moment steel provided at the face of either joint .
6.2.5 In an external joint both the top and bottom bars of the beam shall be provided with anchorage length beyond the inner face of column equal to development length in tension plus 10 times the bar diameter minus the allowance for 90 degree bends (s) In an internal joint, both face bars of the beam shall be taken continuously through the column.
6.2.6 The longitudinal bars shall be spliced, only if hoops are provided over the entire splice length at a spacing not exceeding 150 mm.The lap length shall not be less than the bar development length in tension.
Lap splices shall not be provided
Within joint. (b) Within a distance of 2 d from joint face and (c) Within a quarter length of member where flexural yielding may generally occur under the effect of earthquake forces . Not more than 50 percent of bars shall be spliced at one section .

66. Ductile Detailing Confirming to IS:13920

67. Ductile Detailing Confirming to IS:13920

68. Ductile Detailing Confirming to IS:13920

69. Ductile Detailing Confirming to IS:13920

70. EARTHQUAKE RESISTANT DESIGN AND DETAILING

71. EARTHQUAKE RESISTANT DESIGN AND DETAILING

72. EARTHQUAKE RESISTANT DESIGN AND DETAILING

73. EARTHQUAKE RESISTANT DESIGN AND DETAILING

76. Do’s and Don’t of reinforcement detailing of RCC members

81. REFERENCES:
IS:1893-:2002 Criteria for Earthquake Resistant Design of Structures.
Earthquake Tips by IIT Kanpur and BMTPC
Limit State Methods of RCC Design by A.K.Jain
Torsional effect and Regularity Condition in RC Buildings by Eduardo COSENZA , Gaetano MANFREDI and Roberto

82. THANKING YOU