Reinforced Concrete Analysis of multi storey

1. 1
Analysis and Design of a Multi-storey
Reinforced Concrete Building
United Arab Emirates University
College of Engineering
Civil and Environmental Engineering Department
Graduation Project II
Second Semester 2007/2008
Prepared
Sultan Saif Saeed Alneyadi 200203903
Sultan Khamis AL-shamsi 200101595
Hasher Khamis AL-azizi 200106031
Rashed Hamad AL-Neyadi 200204018
Abdulrahman Abdulla Jarrah 200210915
Adviser
Dr. Usama Ebead

2. 2
Outline
 Objectives
 Summary
 General Approach
 Building Types
 Concrete
 Structural Elements
 Slabs
 Flat Slab
 Design of Flat Slab
 Columns
 Rectangular Columns
 Design of Rectangular Columns
 Shear walls
 Design of Shear Walls
 Foundations
 Pile Group
 Design of Pile Group
 Economic Impact
 Enviromental Impact
 Conclusion

3. 3
Objectives
The Objectives of the Project are:-
 Carrying out a complete analysis and design of the main
structural elements of a multi-storey building including slabs,
columns, shear walls and foundations
 Getting familiar with structural softwares ( SAFE ,AutoCAD)
 Getting real life experience with engineering practices

4. 4
Summary
 Our graduation project is a residential building in Abu- Dhabi.
This building consists of 12 repeated floors.

5. 5
General Approach
 Obtaining an architectural design of a regular residential multi-
storey building.
 Al-Suwaidy residential building in Abu Dhabi.
 Establishing the structural system for the ground, and repeated
floors of the building.
 The design of column, wind resisting system, and type of
foundations will be determined taking into consideration the
architectural drawings.

6. 6
Types of building
 Buildings are be divided into:
 Apartment building
 Apartment buildings are multi-story buildings where three or more
residences are contained within one structure.
 Office building
 The primary purpose of an office building is to provide a workplace and
working environment for administrative workers.

7. 7
Residential buildings

8. 8
Office buildings

9. 9
Concrete Mixtures
 Concrete is a durable material which is ideal for many jobs.
 The concrete mix should be workable.
 It is important that the desired qualities of the hardened concrete
are met.
 Economy is also an important factor.

10. 10
Structural Elements
Any reinforced concrete structure consists of :
 Slabs
 Columns
 Shear walls
 Foundations

11. 11
Flat Slab Structural System
Flat slab is a concrete slab which is reinforced in two directions
 Advantages
 Disadvantages

12. 12
Types of Flat slab

13. 13
Defining properties
 Slab thickness = 23 cm
 Concrete compressive strength = 30 MPa
 Modules of elasticity of concrete = 200 GPa
 Yielding strength of steel = 420 MPa
 Combination of loads (1.4Dead Load + 1.6 Live Load)

14. 14
ACI 318-02
 ACI 318-02 contains the current code requirements for
concrete building design and construction.
 The design load combinations are the various
combinations of the prescribed load cases for which the
structure needs to be checked.
1.2 DL + 1.6 LL

15. 15
15
Flat Slab Analysis and Design
 Analyzing of flat slab mainly is done to find
1. Shear forces.
2. Bending moment.
3. Deflected shape.
4. Reactions at supports.

16. 16
16
Results and Discussion
 Deflection

17. 17
Results and Discussion
Reactions at supports must be checked by a simple method.

18. 18
Flat Slab Reinforcement

19. 19
Columns
 It is a vertical structural member supporting axial
compressive loads, with or with-out moments.
 Support vertical loads from the floors and roof and
transmit these loads to the foundation.

20. 20
Types of column
Spiral column Rectangular
column
• Tied Columns
Over 95% of all columns in building in non-seismic regions are tied columns
• Spiral Columns
Spiral columns are generally circular. It makes the column more ductile.

21. 21
Steel Reinforcement in Columns
 The limiting steel ratio ranges between 1 % to 8 %.
 The concrete strength is between 25 MPa to 45 Mpa.
 Reinforcing steel strength is between 400 MPa to 500 Mpa.

22. 22
Design procedure
1. Calculate factored axial load Pu
2. Select reinforcement ratio
3. Concrete strength = 30 MPa, steel yield strength = 420 MPa
4. Calculate gross area
5. Calculate area of column reinforcement, As, and select rebar
number and size.

23. 23
Columns to be designed

24. 24
Guidelines for Column Reinforcement
 Long Reinforcement
 Min. bar diameter Ø12
 Min. concrete covers 40 mm
 Min. 4 bars in case of tied rectangular or circular
 Maximum distance between bars = 250 mm
 Short Reinforcement ( Stirrups)
Least of:
 (16)×diameter of long bars
 least dimension of column
 (48)×diameter of ties
dc
S
Asp

25. 25
Column Design
c
s A
A 01
.
0
 8- # of bars =

26. 26
Reinforcement of Columns

27. 27
Shear walls
 A shear wall is a wall that resists
lateral wind loads which acts
parallel to the plane of the wall.

28. 28
Shear walls
 Wind results in a pressure on the surface of the building
 Pressure increases with height
 Positive Pressure, acts towards the surface of the building
 Negative Pressure, acts away from the surface of the building
(suction)

29. 29
Wind pressure
 q = Velocity pressure
 (Wind speed, height and exposure condition)
 G = Gust factor that depends on the building stiffness
 Cp = External pressure coefficient

30. 30
Gust G Factor & External pressure Cp coefficient
 for Stiff Structures take G =0.85
 Windward Wall, Cp = +0.8
 Leeward Wall, Cp = varies between -0.2 & -0.5
 Depending on the L/B Ratio
 L/B = 18.84 m /26.18 m = 0.719 < 1 then , Cp = -0.5

31. 31
Velocity Pressure
 V = 160 km/h
 Kz = To be determined from the equations
 Kzt = 1 (level terrain adjacent to the building – not on hill)
 Kd = 0.85 (rectangular building)
 I = 1 (use group II)

32. 32
Important factor
32

33. 33
33
Velocity Exposure Coefficient ( Kz)

34. 34
34
Design of the wind force
 North south direction

35. 35
35
Shear wall axial reactions

36. 36
36
Calculating Velocity Pressure
145 km/h
0.85
1
1
V
(km/hr)
145
α 9.5
Zg 274.32
Kzt 1
Kd 0.85
I 1
G 0.85
Cp
(windward)
0.8
Cp (leeward) -0.5
B (m) 26.18
Level
Height
(z)
Tributary
Height
(ht )
Kz qz (kn/m2)
12 43 1.75 1.36 1.150225
11 39.5 3.5 1.34 1.129849
10 36 3.5 1.31 1.107994
9 32.5 3.5 1.28 1.084391
8 29 3.5 1.25 1.058688
7 25.5 3.5 1.22 1.030406
6 22 3.5 1.18 0.998873
5 18.5 3.5 1.14 0.963092
4 15 3.5 1.09 0.921495
3 11.5 3.5 1.03 0.871364
2 8 3.5 0.95 0.807270
1 4.5 4 0.85 0.715176

37. 37
37
Design of the wind pressure
G 0.85
Cp (windward) 0.8
Cp (leeward) -0.5
B (m) 26.18
qb = qz (at the top of the building)
Level
Height
(z) m
Tributary
Height
(ht ) m
Kz qz (kn/m2)
Design Wind Pressure(KN/m^2) Design Wind Force (KN)
wind ward
(qz G CP)
lee ward
(qb G CP)
wind ward
(qz G CP)(B)(ht )
lee ward
(qb G
CP)(B)(ht )
Total
(floor level)
Moment
(KN.m)
12 43 1.75 1.36 1.150225 0.782153 -0.488846 35.834345 -22.396465 58.230810 2503.924826
11 39.5 3.5 1.34 1.129849 0.768297 -0.488846 70.399094 -44.792931 115.192025 4550.084972
10 36 3.5 1.31 1.107994 0.753436 -0.488846 69.037332 -44.792931 113.830262 4097.889443
9 32.5 3.5 1.28 1.084391 0.737386 -0.488846 67.566683 -44.792931 112.359614 3651.687445
8 29 3.5 1.25 1.058688 0.719908 -0.488846 65.965161 -44.792931 110.758092 3211.984664
7 25.5 3.5 1.22 1.030406 0.700676 -0.488846 64.202965 -44.792931 108.995896 2779.395349
6 22 3.5 1.18 0.998873 0.679233 -0.488846 62.238149 -44.792931 107.031079 2354.683748
5 18.5 3.5 1.14 0.963092 0.654903 -0.488846 60.008720 -44.792931 104.801650 1938.830531
4 15 3.5 1.09 0.921495 0.626617 -0.488846 57.416871 -44.792931 102.209802 1533.147032
3 11.5 3.5 1.03 0.871364 0.592527 -0.488846 54.293292 -44.792931 99.086222 1139.491559
2 8 3.5 0.95 0.807270 0.548944 -0.488846 50.299721 -44.792931 95.092651 760.7412106
1 4.5 4 0.85 0.715176 0.486320 -0.488846 50.927427 -51.191921 102.119348 459.5370657
sum 1229.707452 28981.39785

38. 38
38
Computing total moment acting toward N-S Direction
M = total floor level *height (z)

39. 39
39
W-E Direction Computation
L= 26.18
B=
18.84
Level
Height
(z) m
Tributary
Height
(ht ) m
Kz qz (kn/m2)
Design Wind Pressure(KN/m^2) Design Wind Force (KN)
wind ward
(qz G CP)
lee ward
(qb G CP)
wind ward
(qz G CP)(B)(ht )
lee ward
(qb G CP)(B)(ht )
Total
(floor level)
Moment
(KN.m)
12 43 1.75 1.36 1.150225 0.7821531 -0.48885 25.7875879 -16.1172424 41.9048304 1801.907705
11 39.5 3.5 1.34 1.129849 0.7682974 -0.48885 50.6615328 -32.2344849 82.8960177 3274.392699
10 36 3.5 1.31 1.107994 0.7534359 -0.48885 49.6815633 -32.2344849 81.9160482 2948.977735
9 32.5 3.5 1.28 1.084391 0.7373860 -0.48885 48.6232356 -32.2344849 80.8577205 2627.875916
8 29 3.5 1.25 1.058688 0.7199079 -0.48885 47.4707271 -32.2344849 79.7052120 2311.451149
7 25.5 3.5 1.22 1.030406 0.7006763 -0.48885 46.2025923 -32.2344849 78.4370772 2000.145469
6 22 3.5 1.18 0.998873 0.6792333 -0.48885 44.7886449 -32.2344849 77.0231298 1694.508855
5 18.5 3.5 1.14 0.963092 0.6549025 -0.48885 43.1842734 -32.2344849 75.4187583 1395.247028
4 15 3.5 1.09 0.921495 0.6266165 -0.48885 41.3190931 -32.2344849 73.5535780 1103.30367
3 11.5 3.5 1.03 0.871364 0.5925275 -0.48885 39.0712612 -32.2344849 71.3057461 820.0160796
2 8 3.5 0.95 0.807270 0.5489438 -0.48885 36.1973543 -32.2344849 68.4318392 547.4547138
1 4.5 4 0.85 0.715176 0.4863200 -0.48885 36.6490728 -36.8394113 73.4884841 330.6981787
sum 884.9384415 20855.9791983

40. 40
40
Design of Shear Wall
 East west direction
 North south direction

41. 41
41
Interaction Diagram

42. 42
42
Shear Wall Reinforcement

43. 43
Foundations
 Foundations are structural components used to support
columns and transfer loads to the underlying Soil.
Foundations
Isolated Combined Strap wall Raft
Shallow
footing footing footing footing footing
Caissons Piles
Deep

44. 44
Pile foundation
 Our building is rested on a weak soil formation which
can’t resist the loads coming from our proposed building,
so we have to choose pile foundation.
Pile cap
Piles
Weak soil
Bearing stratum

45. 45
Pile foundation
 Piles are structural members that are made of steel,
concrete or timber.

46. 46
Function of piles
 As with other types of foundation, the purpose of a pile
foundation is:
 To transmit a foundation load to a solid ground
 To resist vertical, lateral and uplift load
 Piles can be
 Timber
 Concrete
 Steel
 Composite

47. 47
Concrete piles
General facts
 Usual length: 10m-20m
 Usual load: 300kN-3000kN
Advantages
 Corrosion resistance
 Can be easily combined with a concrete superstructure
Disadvantages
 Difficult to achieve proper cutoff
 Difficult to transport

48. 48
Pile foundation
Piles can be divided in to two major categories:
1. End Bearing Piles
If the soil-boring records presence
of bedrock at the site within a reasonable depth,
piles can be extended to the
rock surface
2. Friction Piles
When no layer of rock is present depth at a site, point bearing piles become very
long and uneconomical. In this type of subsoil, piles are driven through
the softer material to specified depths.

49. 49
Pile Cap Reinforcement
 Pile caps carrying very heavy point loads tend to produce high
tensile stresses at the pile cap.
 Reinforcement is thus designed to provide:
 Resistance to tensile bending forces in the bottom of the cap
 Resistance to vertical shear

50. 50
Design of the pile cap
 bearing capacity of one pile:
Rs = α ⋅ Cu ⋅ As .L
 Length of pile penetration L = 18 meters
 Adhesion factor of soil (clay) α = 0.8
 Untrained shear strength Cu = 50
 Diameter = 0.9 m
 For piles with diameter 0.9 m
Rs = 2035.75 KN

51. 51
First type
 This section shows how pile caps are designed to carry
only vertical load, and the equation used to determine
the resistance of cap is
Where
P is the strength of the pile cap per one pile
Q is the total force acting on the pile cap
n is the number of piles used to support the pile cap
n
Q
P i
i 

52. 52
Columns layout & Reactions ( Vertical Load )
Column Reaction Total Reaction
kN kN
1 129.63 1555.56
2 246.85 2962.2
8 382.66 4591.92
10 393.38 4720.56
21 458.35 5500.2
23 400.85 4810.2
24 627.74 7532.88
25 384.14 4609.68
30 158.3 1899.6
32 355.26 4263.12

53. 53
Design of pile cap (Vertical Load only)
 Pile Cap 2
 Reaction = 4610.4 kN
 Pile diameter = 0.9 m
 Capacity for one pile = 0.8 * 50 * 18 * π * 0.9 = 2035.75 KN
 Need 3 piles
 Length between piles = (2*0.3) + (3*0.9) + (2*0.9)*2 =6.9 m
 Width = 1.5 meters
 Actual forces on each pile = = 1536.8 kN
n
i
Q
i
P 

54. 54
Second type
 Second type
 This section shows how pile caps are designed to carry
vertical load and lateral loads ( Bending Moment), and the
equation used to determine the resistance of cap is



 2
r
r
M
n
Q
P
i
i
i

55. 55
Shear walls layout & reactions
wall M (KN.m) N (KN)
W1 14072.12 12285.6
W2 366.048 3596.76
W3 366.048 3026.88
W4 5719.5 3605.04
W5 30.65295 4128
W6 301.6143 1899.6
W10 10141.2 32.80882
W11 2402.52 32.80882
W13 20978.4 6700.246
W14 3297.6 6700.246
W15 2040 262.4706
W16 5470.2 262.4706
W17 7262.76 7903.641
W18 8571.48 7086.706

56. 56
Design of pile cap (Vertical Load & moment)
 Shear wall # (1):
 M = 14072.11561
 Q = 12285.6
 Assume 8 piles
KN
P
So
P
KN
P
So
P
r
r
M
n
Q
P
Pile
of
Capacity
Pile
of
Capacity
75
.
2035
,
676
.
24
)
26
.
4
(
*
11561
.
14072
8
6
.
12285
75
.
2035
,
676
.
24
)
909
.
1
(
*
11561
.
14072
8
6
.
12285
2
2
2












57. 57
Economical impact
 Reinforced concrete is proven to be a very economical
solution in the UAE.
 the most affordable solution for multistory building such
as the one we are making the analysis and design for.

58. 58
Environmental impact
 Although the cement production is environmentally
challenging, the final product of a reinforced concrete
building is environmentally friendly.

59. 59
Gantt Chart

60. 60
Conclusion
 We have applied our gained knowledge during our graduation
project
 We are able to use structural software ( SAFE )
 We have practiced real life engineering practices
 This GP enables us to go into the market with an excellent
background regarding design of RC
 At this point, we would like to thank all instructors, engineers,
and Al Ain Consultant Office for their grateful effort.

61. 61