Complete introduction to the design and design concepts, design of structural members like slabs, beams, columns, footing etc. along with their calculation and Detailing through structural drawings.

1. Presented by- D P NITHIN
M tech (Structures)
ANALYSIS AND DESIGN OF G+3
RESIDENTIAL BUILDING
Overview:
Complete introduction to the design and design concepts, design of structural
members like slabs, beams, columns, footing etc. along with their calculation and
Detailing through structural drawings.

2. OBJECTIVES
The objectives of the project work are:
To plan and study the detailing of architectural drawings.
To model and analyze the structure using ETABS software.
To design various structural components like beams, columns, slabs and
footings.
To provide detailing of the various structural members using
AUTOCAD.
To prepare excel sheets for design of structural members
2

3. DESIGN PHILOSOPHY
LIMIT STATE METHOD (LSM)
Limit state is defined as the acceptable limit of safety and serviceability
requirements before failure. The most important limit states which are
considered in design are:
LIMIT STATE OF
COLLAPSE
Flexure
Compression
Shear
Torsion
LIMIT STATE OF
SERVICEABILITY
Deflection
Cracking
3

4. PARTIAL SAFETY FACTORS:
Partial safety factor for materials: IS 456:2000 states that γm for concrete
and steel should be taken as 1.5 and 1.15, respectively when assessing the
strength of the structures or structural members employing limit state of
collapse.
Partial safety factor for loads : (Table 18 ,Clause 36.4.1 of IS 456-2000)
Load Combination Limit state of collapse Limit state of
serviceability
DL IL WL
OR EQ
DL IL WL
OR
EQ
DL+IL 1.5 1.5 - 1 1 -
DL+WL 1.5 - 1.5
0.9 - 1.5
DL+IL+WL 1.2 1.2 1.2 1 0.8 0.8
4

5. BUILDING DESCRIPTION
The Ground floor is designed for parking and as well for office area and
above floors are designed for residential dwellings.
 Type of structure : Reinforced Concrete structure
 Type of Building: : Residential Building
 Site dimension : 30 X 60 (feet)
 Number of floors : G+3
 Floor to Floor height : 3.15 m
 Building Location : Chikamagalur
 Safe Bearing Capacity of soil, SBC : 180 kN/m2
 Seismic Zone : Zone 2 (IS 1893-Part 1)
5

6. ARCHITECTURAL PLANS
6

7. 7

8. DESIGN INPUT
The grades of concrete and steel used for design are as follows:
Structural
Components
Grade of concrete
(fck)
Grade of steel
(fy)
Foundation M25 Fe 500
Column M30 Fe 500
Beams M25 Fe 500
Slab M25 Fe 500
 Size of Beam:
B = 230 x 500
 Size of Column
C = 230 x 450
 Slab thickness
125mm
8

9. LOADS CONSIDERED
DEAD LOADS:
The unit weights of the building materials are taken from IS 875-Part 1
Material Density
(kN/m3)
Reinforced Concrete 25
Plain Concrete 24
Steel 78.54
Engineering Bricks 21.20
Cinder filling 7
Floor Finishes 1.20 kN/m2
Terrace Level Floor Finish 1.80 kN/m2
Partition Walls 1.0 kN/m2
WALL LOADS:
a.225mm thk Wall = 0.23 x (3.15-0.45) x 21.20 = 12.92 kN/m
b.150mm thk Wall = 0.15 x (3.15-0.45) x 21.20 = 8.58 kN/m
c.Parapet Wall =0.10 x 1.00 x 21.20 = 2.12 kN/m
9

10. LIVE LOADS ON SLAB:
The Imposed floor loads for different occupancies is taken from Table 1 of
IS 875 (Part 2)-1987
Occupancy Live Load
(kN/m2)
Bedroom 2.0
Dining and Kitchen 2.0
Hall 2.0
Toilet and Bath 2.0
Staircase 3.0
Balcony 3.0
OHT 1.79
10

11. WIND LOAD CALCULATION
Wind loads for design of structures shall be based on the design wind speeds as
per IS 875 (Part 3):2015.
Design wind velocity=Vz = k1 k2 k3 k4Vb
= 1 x 1.01 x 1 x 1 x 33
Vz = 33.33 m/s
Design wind pressure= Pz = 0.6 Vz
2 = 0.60 x 33.332
Pz=0.665 kN/m2
Where, Pz =Design Wind Pressure in N/m2 at height Z
Vz =Design Wind Velocity in m/sec.
Parameters Values
Basic wind speed (Vb) 33m/s
k1 ( Risk coefficient) 1
k2( coefficient based on terrain,
height)
1.01
k3(Topography factor) 1
k4 ( Cyclonic factor) 1
11

12. WIND PRESSURE COEFFICIENTS:
Greater horizontal Dimension of the Building, l = 15.263 m
Lesser horizontal Dimension of the Building, w = 7.47 m
Height of the Building, h =14.1 m
h / w= 1.890
l / w= 2.043
Coefficient along X direction(00):
(Table 5 ,Clause 7.3.3.1 IS 875-Part 3 2015)
Windward = 0.70
Leeward = 0.40
 Coefficient along Y direction(900):
Windward = 0.80
Leeward = 0.10
12

13. SEISMIC LOAD:
Earthquake loads are assessed in the structural design based on IS 1893 (Part 1) :2016.
Time Period (Cl. 7.6.1, IS 1893-part 1:2016)
Ta = = 0.09 x 15.60/ 7.47 = 0.513 s in X-direction
= 0.09 x 15.60/ 15.263 = 0.359 s in Y-direction
h= Height of the Building
d= Base Dimension at Plinth level along the considered direction of Earthquake shaking
Parameters Values
Zone II
Soil type II (Medium)
Zone factor 0.10 (From Table 3 of IS 1893-
Part1:2016)
Importance factor 1.0 (From Table 8 of IS 1893-
Part1:2016)
Response Reduction factor 3 (From Table 9 of IS 1893-
Part1:2016)
13

14. 14
ANALYSIS MODEL

15. 15
Load patterns
Load cases

16. 16
Mass source Data
Load Combinations as per Table 18,IS 456 :2000

17. 17
RESULTS
Bending Moment Diagram Shear Force Diagram

18. STRUCTURAL DESIGN
SLABS
RC Slabs constitute the most common type of structural elements used to cover
floor and roof of the buildings.
One way slab Load transfer
Two way slab Load transfer
18

19. STRUCTURAL DESIGN
DESIGN OF SLAB
Grade of Concrete, fck = 25 N/mm2
Grade of Steel, fy = 500 N/mm2
Length along longer span, Ly = 4.34 m
Length along shorter span, Lx = 3.61 m
Ly/Lx = 1.20 Design as Two way slab
Overall Depth of Slab, D =125 mm
Clear Cover = 20 mm
Bar Dia. = 8 mm
Effective Depth, d = 101 mm
19

20. Load Calculation
Self Weight of the Slab = 3.125 kN/m2
Floor Finish = 1.2 kN/m2
Live Load = 2 kN/m2
Total Load, W = 6.325 kN/m2
Total Factored Load, Wu =9.488 kN/m2
Boundary Condition =Two adjacent edges discontinuous
Negative Positive
αx 0.060 0.045
αy 0.047 0.035
Moment Coefficients(From Table 26, IS 456-2000)
Bending Moments
Support Moments Span Moments
Mux 7.42 kNm 5.57 kNm
Muy 5.81 kNm 4.33 kNm
20

21. Check for required Depth
dreq = Sqrt(Mu/0.133*fck*b) = 47.23mm
dpro = 101 mm Depth provided is Safe.
Reinforcement
Span
Short span
Mux = 5.57 kNm
Mu / (bd2) = 0.55 N/mm2
pt =0.13 %
Ast(req) = 131 mm2
Bar Dia. = 8 mm
Spacing (Required) = 384 mm
Spacing (provided) = 270 mm
#8 @ 270 C/C
Long Span
Muy = 4.33 kNm
Mu / (bd2) = 0.5 N/mm2
pt = 0.12 %
Ast (req) = 121 mm2
Bar Dia. = 8 mm
Spacing (Required) = 415 mm
Spacing (provided) = 270 mm
#8 @ 270 C/C #8 @ 270 C/C
Support
Short span
Mux =7.42 kNm
Mu / (bd2) = 0.73 N/mm2
pt = 0.17 %
Ast (req) = 172 mm2
Bar Dia. = 8 mm
Spacing (Required) = 292 mm
Spacing (provided) =270 mm
#8 @ 270 C/C
Long Span
Muy = 5.81 kNm
Mu / (bd2) = 0.67 N/mm2
pt = 0.16 %
Ast (req) = 162 mm2
Bar Dia. = 8mm
Spacing (Required) = 310 mm
Spacing (provided) =270 mm
21

22. Check for Shear
Shear Force, Vu = 17.13 kN
Shear Stress, τv = Vu/ (b*d)
τv =0.17 N/mm2
Ast(pro) =335 mm2
pt(pro) = 0.33 %
Permissible Shear Stress
τc =0.402N/mm2 (From Table 19 IS 456:2000)
τv < τc The Slab is Safe for Shear
Check for Deflection
L/d (basic) = 26
fs = 0.58fy*(Ast required/Ast Provided) = 145.62 N/mm2
Modification Factor, kt= 1.90
L/d (max) = 49.40
L/d (provided) = 42.97
L/d (provided) < L/d (max) Slab is Safe for Deflection
22

23. 23
DETAILING OF SLAB

24. DESIGN OF BEAM
Grade of Concrete, fck = 25 N/mm2
Grade of Steel, fy = 500 N/mm2
Clear Cover = 25 mm
Width, b = 250 mm
Overall Depth, D = 500 mm
Bar Dia. =16 mm
Effective Depth, d = 467 mm
Effective Span, Le = 5.716 m
Results from Etabs(Beam B47 – First Floor)
TOP BOTTOM TOP
LEFT MID RIGHT
Mu (kNm) 83 113.21 142.58
Vu( kN) 168.04 26.78 155.29
Mu/bd2(N/mm2) 1.65 2.26 2.84
Pt (%) 0.414 0.59 0.513
Ast (mm2) 444.68 633.72 827.37
Bar Dia.(mm) 16 20 20
No. 3 3 3
Ast(pro)( mm2) 603.19 942.48 942.48 24

25. Check for Depth
Mulim = 0.133*fck*b*d2 = 191.19 kNm > Mu
Provided Depth is Safe
Check for Shear
LEFT
Shear Stress,τv = Vu / bd = 1.46 N/mm2
Permissible Shear Stress τc = 0.50 N/mm2
τc < τv hence design for shear
Vus =114.34 kN
Provide,
Bar dia. = 8 mm
No. of legs = 2
Spacing Required = 178.62 mm
Minimum Spacing = 175 mm
2L-#8 @175 C/C
RIGHT
Shear Stress,τv =Vu / bd = 1.35 N/mm2
Permissible Shear Stress τc =0.59 N/mm2
τc < τv hence design for shear
Vus = 92.19 kN
Bar dia. = 8 mm
No. of legs = 2
Spacing Required = 220.58 mm
Spacing = 200 mm
2L-#8 @200 C/C
Check for Deflection
L/d (basic) = 26
fs = 0.58fy*(Ast required/Ast Provided) =213.79 N/mm2
Modification Factor, kt= 1.1
L/d (max) = 28.6
L/d (pro) = 12.24
L/d(pro)< L/d (max)
Beam is Safe for Deflection
25

26. 26
DETAILING OF BEAM (B47 & B39 of First Floor)

27. DESIGN OF COLUMN C2
Grade of concrete (fck) 30 N/mm2
Grade of steel (fy) 500 N/mm2
Clear cover 40 mm
Column size
B 230mm
D 450mm
Clear length ,(l) 3.15m
Effective length factor 0.65
Effective length (le) 2.048m
Forces from Etabs
Pu =657.33 kN
Mux =78.725 kN-m
Muy =60.629 kN-m
Check for eccentricity
ex = (l/500) + (D/30) = (3150/500) + (450/30) = 21.3 mm > 20 ex = 21.30mm
ey = (l/500) + (B/30) = (3150/500) + (230/30) = 13.97 mm < 20 ey = 20 mm ( as per IS
456:2000)

28. Minimum Bending Moment due to eccentricity
Mex = Pu*ex = 14.00 kNm < Mux
Mey = Pu*ey = 13.15 kNm < Muy
Mux = 78.725 kNm
Muy = 60.629 kNm
Check for Slenderness
le / (B or D) = 8.90 < 12
Column is not Slender
Assume pt = 1.5 %
Ag = (B x D) = (230 x 450) =103500 mm2
From Chart 63, SP 16
Puz /Ag = 19
Puz = 1966.5 kN
d' = 50
Bar Dia. = 20 mm

29. Check for biaxial bending
(Mux/Mux1)αn + (Muy/Muy1)αn ≤ 1
To Calculate αn
Pu/Puz = (657.33/1966.5)
Pu/Puz = 0.334
For the values Pu/Puz = 0.2 to 0.80 ,the values of αn varies linearly from 1.0 to 2.0
αn = 1.174
(Mux/Mux1)αn + (Muy/Muy1)αn
(78.725/153.698)1.174 + (60.629/125.75)1.174 = 0.851 ≤ 1
(Mux/Mux1)αn + (Muy/Muy1)αn ≤ 1
Hence Column is Safe.
Mux1 From Chart 48 of SP -16
d’/D 0.111
P/fckbD 0.212
p/fck 0.05
Mux/fckbD2 0.11
Mux1 153.698 kN-m
Muy1 From Chart 48 of SP -16
d’/B 0.217
P/fckbD 0.212
p/fck 0.05
Mux/fckbD2 0.09
Mux1 125.75 kN-m

30. 30
Reinforcement Calculation
Calculation of longitudinal reinforcement
Considering pt=1.5 %
Ast = (1.5/100 x 230 x 450)
Ast = 1552.5 mm2
provide 4-#20 and 4-#12
Ast pro = 1709.248 mm2
pt pro (%) = 1.651
Calculation of lateral ties
According to IS 456:2000 Clause 26.5.3.2
Assume 8 mm dia
Spacing
Least lateral dim = 230 mm
16 dia(lesser of column) = 192 mm
Max spacing = 300 mm
Spacing min = 192 mm
Provide lateral ties # 8 @ 175 c/c

31. 31
DESIGN OF FOOTING (BASE 2)
Grade of concrete (fck) 25 N/mm2
Grade of steel (fy) 500 N/mm2
Clear cover 50mm
SBC of soil 180 kN/m2
Column size
b 230mm
D 450mm
Depth of foundation (Df) 1.50m
Forces from Etabs
P=527.228 kN Pu=790.842 kN
Mx=35.372 kN-m Mux=53.058 kN-m
My=24.636 kN-m Muy=36.954 kN-m
Depth of foundation is calculated based on Rankine’s formula
(Df) =
𝑆𝐵𝐶
γ𝑠
1−sin ϕ
1+𝑠𝑖𝑛ϕ
2

32. 32
Footing size
Load on column = 527.228 kN
Self weight of Footing = 10% of Load from the column
= (0.10 x 527.228) = 52.72 kN
Total load=Load on column + Self weight of footing
= 527.228 + 52.72
=579.95 kN
Area of footing required =
𝑇𝑜𝑡𝑎𝑙 𝐿𝑜𝑎𝑑
𝑆𝐵𝐶
=
579.95
180
= 3.22 m2 L=2.75m B=1.75m
Provide Footing size ( 2.75m x 1.75m)
Area provided = 4.812 m2
Check for pressure
Pmax = (P/A) + (Mx/Zx) + (My/Zy)
Pmax = 143.14 kN/m2
Pmax < SBC Therefore it is SAFE
Pmin = (P/A) - (Mx/Zx) - (My/Zy)
Pmin = 75.96 kN/m2 > 0 Therefore it is SAFE
Zx = (B x L2/6) = 2.205729
Zy = (L x B2/6) = 1.403646

33. Check for required Depth
dreq = sqrt (Mu/0.133 x fck x b)
d required = 206.64 mm `
Provide D = 600mm
d(provided) = 542 mm
dpro > d req Depth provided is Safe
Reinforcement Calculation:
Mu / (bd2) = 0.483 N/mm2
Percent of tension reinforcement (pt )= 0.114 %
Min. pt = 0.120 % (As per IS 456: 2000)
Ast(req) = 720 mm2
Bar dia. = 12 mm
Spacing (Required) = 157mm
Spacing (provided) = 150mm
Provide # 12 @ 150 C/C on both ways
Bending Moment Calculation
Mu = 1.5 x (p*l2/2)
1.5 x (143.14 x 1.152/2)= 141.98 kNm

34. Check for One way Shear
Vu = Wu*Lc (Lc= Length at Critical section, d is taken from Column edge)
Lc = 0.608 m
Vu =130.55 kN
Nominal shear stress τv = Vu/(bd)
τv = 0.241 N/mm2
Ast(pro) = 753.98mm2
pt(pro) = 0.139 %
Permissible shear τc = 0.29 N/mm2
τv < τc
Therefore it is Safe for One way Shear
L
B
d Lc

35. Check for Two way Shear (Punching Shear)
Critical section
a = D+(d/2)+(d/2) = 0.992m
b = b +(d/2)+(d/2) = 0.772m
Critical Section Perimeter = 2(a+b)
=2(0.992+0.772)
= 3.528m
Punching Load, Vu= (Pu-1.5xaxbxp)
Vu = 626.41 kN
Punching Shear =
τv = 0.239 N/mm2
Permissible Punching Shear = k * τc
τc = 0.25√fck = 1.25 N/mm2
βc = Shorter dimension of Column / Longer dimension of Column = (0.23/0.45) =0.511m
k = 0.5+βc < 1
=1.01
k = 1
k * τc = 1.25 N/mm2
k τc > τv
Therefore Footing is Safe for Two way shear
L
B
d/2
d/2
a
b

36. 36
DETAILING OF FOOTING

37. 37
DESIGN OF STAIRCASE
Data
Unit weight of Concrete 25 kN/m3
Grade of concrete 25 N/mm2
Grade of steel 500 N/mm2
Span of Staircase, L 3.64 m
Floor to floor height, H 3.15 m
Diameter of Reinforcement 12 mm
Nominal cover to the reinforcement, d' 20 mm
Dimension of staircase
Rise 150 mm
Tread 250 mm
Waist slab thickness 150 mm
No of risers 21
No of threads 20
Width of landing 2 m
No of threads in each flight 10
Total width of threads in landing 3 m

38. 38
Loads
Self weight of slab 3.125 3.65 kN/m2
Floor finish 1 1 kN/m2
Live load 3 3 kN/m2
Stairs weight 0 1.5 kN/m2
Total load 7.125 9.15 kN/m2
Factored load 10.6875 13.725 kN/m2
Bending moment Flight 1 = Flight 2
Ultimate moment, Mu 27.78 kNm
Depth of slab (d req) 91.41 mm
Depth of slab (d pro) 99 mm
dpro > dreq Safe
Main reinforcement
Mu/bd2 2.84 N/mm2
pt (req) 0.777 %
Main bar dia 12 mm
Ast (req) 769.23 mm2
Spacing (req) 147.03 mm
Spacing (pro) 125 mm
Ast (pro) 904.78 mm2
pt (pro) 0.92 %
Provide # 12 @ 125 c/c

39. 39
Distribution reinforcement
For distribution steel considering minimum i.e. 0.12% of Gross area
Ast 150 mm2
Dia of bars 8 mm
Spacing 335.11 mm
Spacing (pro) 200 mm
Provide #8 @ 200 c/c
Check for shear
Shear force, Vu 19.451 kN
Shear stress, τv 0.196 N/mm2
Permissible shear stress, τc 0.617 N/mm2
τv < τc Safe

40. 40
DETAILING OF STAIRCASE

41. REFERENCES:
P. C. Varghese, “Limit State Design of Reinforced Concrete”, Text Book,
Second edition, PHI Learning Private Limited,2015.
IS 456, “Plain and Reinforced Concrete”, Code of Practice, 2000.
IS 875(Part 1), “Design loads (Other than Earthquake) for Buildings and
Structures”, Dead Loads - Unit weights of Building materials and stored
materials, Code of Practice, 1987.
IS 875(Part 2), “Design loads (Other than Earthquake) for Buildings and
Structures”, Imposed Loads, Code of Practice, 1987.
IS 875(Part 3), “Design loads (Other than Earthquake) for Buildings and
Structures”, Wind Loads, Code of Practice, 2015.
IS 1893 (Part 1), “Criteria for Earthquake Resistant Design of Structures”, Code
of Practice, 25-26, 2016.
SP 16, “Design Aids for Reinforced Concrete to IS 456-1978”, 1980.
SP 34:1987,Handbook on Concrete Reinforcement and Detailing 41

42. THANK YOU
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