Project 1
1. Design a multi-storey Residential Building located in Bangalore using STAAD Pro Connect Edition. The specification must be as follows:
|
Building floors |
G + 6 + R |
|
Plan dimension |
B = 25m , L = 16m |
|
Storey Height |
h = 3.5m |
|
Soil |
Hard soil |
|
Use |
Residential Purpose |
|
Safe Bearing Capacity |
180 kN/m2 |
|
Maximum slab thickness |
150mm |
Assume suitable sections for structural elements. Follow IS456, IS1893 and IS 875
- Prepare a Design Basis Report for the project
- Create structural model using STAAD Pro Connect Edition
- Prepare DL, LL, WL and EQL load calculations as per IS 875 standards
- Design slab element using MS – Excel
- Design beam and column element using STAAD RCDC. Attach the design calculation report.
- Design Foundations using STAAD Foundation.
- Prepare bar bending schedule for beam and column using STAAD RCDC
- Attach necessary sketches and drawings wherever required.
- All stipulations, assumptions and design parameter must adhere to Indian Standards.
Aim:
To design a multi-storey Residentail Building in Banglore using STAAD Pro connect edition.
Procedure:
Unit weight of the materials
Reinforcement Cement Concrete = 25 kN/M3
Plain Cement Concrete = 24 kN/M3
Cement Concrete Screed = 20 kN/M3
Cement Masondry Unit = 22 kN/M3
Structural Steel = 78.5 kN/M3
Soil = 18 kN/M3
Dead load
Floor slab
Slab weight = 3.75 kN/M2 (0.15x25kN/M3)
Partitions = 1.5 kN/M2
Floor finish = 2.5 kN/M2
Miscellaneous = 1 kN/M2
Total Floor Load = 8.75 kN/M2
Roof slab
Slab weight = 3.5 kN/M2 (0.15mx25kN/M3)
Insulations and Water proofing = 0.5 kN/M2
MEP Servies = 0.5 kN/M2
Miscellaneous = 0.5 kN/M2
Total Roof load = 5.25 kN/M2
Live load
Floor load
Common Corridor = 3 kN/M2
Total Floor load = 3 kN/M2
Roof slab
Accessible Roof = 1.5 kN/M2
Total Roof load = 1.5 kN/M2
Design of slab (IS 456)
Span shorter Direction (Clear) ly = 3.125 m
Span longer direction (Clear) lx = 5.50 m
Live Load on the slab LL = 3.00 kN/m²
Compressive strength of concrete fck = 25 N/mm²
Yield strength of concrte fy = 415 N/mm²
Unit weight of concrete Yc = 25.00 kN/M³
UNit weight of floor finish 100 mm Y = 22.00 mm
Clear concrete cover = 25.00 mm
Bearing of slab B = 25.00 mm
Step 1
Span to effective depth ratio l/d = 32
Minimum effective depth d = 97.66 mm
Overall depth D = 127.66 mm
Provide overall depth D = 150.00 mm
Dia of bars for short direction Φ = 10 mm
Dia of bars for long direction Φ = 10 mm
Effective Depth d = 120.00 mm
Loading on the slab
Dead load of the slab (DL) 3.75 kN/m²
Super dead load 5.00 kN/m²
Load on the slab 3.00 kN/m²
Total load on the slab 11.75 kN/m²
Design load = (Total load x Load factor i.e., 1.5) 17.63 kN/m²
Effective span lx = 3.25 m
ly = 5.62 m
Radio ly/lx = 1.732 Two way
1.5 αx 1.75 αy
For native moments (at top) 0.075 0.104683 0.107 0.084
For pasitive moments (at bottom) 0.056 0.103307 0.107 0.063
Step 2
BIM per unit width of slab Mx = αx w lx² My = αy w lx²
For native moments (at top) 19.43 15.59 KN-m/m
For pasitive moments (at bottom) 19.17 11.69 KN-m/m
Shear force, V 0.5wlx 28.60 KN-m/m
Step 3
To check the effecive depth of slab
Mu,lim = 0.138fckbd²
d = 74.55 mm
Step 4
Depth of slab for shear force
τc,max = 3.1 N/mm²
τc = 0.3
k = 1.2 D=200mm
τc = 0.36 N/mm²
τv = Vu / bd
= 0.24 N / mm²
τv < τc < τc,max
0.24 0.36 3.1
SAFE
Step 5 Determination of areas of steel
Mu = 0.87fyAstd(1-Astfy/fckbd)
For Nagative moments Mu Top = 19.43 kN/m
Ast = 561.65 mm²/m
For Positive moments Mu bot = 19.17 kN/m
Ast = 554.27 mm²/m
Step 5.1 Determination of distrubution steel
Astmin = 0.12bd
144 mm²
Step 5.2 Selection of reinforcing bars
Area of bars (Top steel) = 78.5 mm²
Spacing = 140
= 125 mm
Provide 10mm bars at a spacing 125mm
Area of bars (Bottom steel ) = 78.5 mm²
Spacing = 142
= 125 mm
Provide 10mm bars at a spacing 125mm
Calculation of Wind load (IS 875-part 3)
Design Wind Speed Vz = Vb k1 k2 k3 k4 m/s
Basic Wind Speed (Bengaluru) Vb = 33 m/s
Prabability factor k1 = 1
Terrain factor, Catogory for k2 = Category 4 B
Topography factor k3 = 1
Design Wind Pressure Pz = 0.6 Vz²
| Factor | Height | k2 | Vz | Pz | Pz in kN |
| 1 | 3.5 | 0.76 | 25 | 377.40 | 0.38 |
| 2 | 7.0 | 0.76 | 25 | 377.40 | 0.38 |
| 3 | 10.5 | 0.76 | 25 | 377.40 | 0.38 |
| 4 | 14.0 | 0.76 | 25 | 377.40 | 0.38 |
| 5 | 17.5 | 0.76 | 25 | 377.40 | 0.38 |
| 6 | 21.0 | 0.78 | 26 | 397.53 | 0.40 |
| R | 24.5 | 0.84 | 28 | 461.04 | 0.46 |
Calculation of seismic load (IS 1893-Part 1)
Design base Shear Vb = Ah W kN
Design Horizontal Acceleration Coeffiveint
Ah = (z/2).(sa/g)
(R/I)
Zone factor Z = 0.1 Bengalur
Soil Condition factor , Sa/g T= 0.09h
√d
Height of building h = 24.5 m
Base dimension of building Along X = 16 m
Along Z = 25 m
T along X = 0.5513s
T along Z = 0.4410s
Sa/g = 1.814 Along X
Sa/g = 2.268 Along Z
Response reduction factor R = 3
Importance Factor I = 1.2
Horizontal Acceleration Coefficient Ah = 0.0363 Along X
Ah = 3.62812%
Seismic Weight
Area of each floor A = 400 m²
Due to dead load , Typical floor DL = 12.5 kN/m²
W dl = 5000 kN
Due to dead load , Roof DL roof = 9 kN/m²
= 3600 kN
Due to Live load , Typical Floor LL = 3 kN/m²
W ll = 300 kN
Dead to live load , Roof LL = 1.5 kN/M²
W ll = 0 kN
Total Seismic Weight W = 35400 kN
Design Base Shear Vb = 1284.35 Kn
Horizontal Acceleration Coefficeint Ah = 0.0454 Along Z
Ah = 4.53515 %
Seismic Weight
Area of each floor A = 400 m²
Due to dead load , Typical floor DL = 12.5 kN/m²
W dl = 5000 kN
Due to dead load , Roof DL roof = 9 kN/m²
= 3600 kN
Due to Live load , Typical Floor LL = 3 kN/m²
W ll = 300 kN
Dead to live load , Roof LL = 1.5 kN/M²
W ll = 0 kN
Total Seismic Weight W = 35400 kN
Design Base Shear Vb = 1605.44 Kn