Foundation Design using SAFE
Aim:
Foundation design using SAFE.
Procedure :
Unit definition:
Input for the footing design:
Subgrade modulus of soil = (Factor of safety x SBC) / settlement of soil
SBC = 150 kN/`m^2`
FOS for footing = 3
Settlement of soil = 50mm
Subgrade modulus = (3 x 150)/50 = 9000 kN/`m^2`
Column size = 400mm x 400mm
Footing depth = 800mm
Factored axial load = 2000kN
unfactored load = 2000/1.5 = 1333kN.
Dividing equally as dead load & Live load = 1333/2 = 666.65kN
DL = 666.65kN
LL = 666.65kN
Material property definition:
Steel:
HYSD500 is used
Concrete - M25 is used
Definition of section properties:
Mat is defined
slab stiff property is defined
Footing definition:
Load definition:
Define ---> Load pattern ---> define DL & LL
Assigning the load:
Select the column joint point--->click Assign --->joint load---> define the DL & LL
Define ---> Load combinations
Ultimate & Serviceability load combinations are defined
Design strips on the model:
Analyse the model
Deflection check:
Maximum deflection is 4.72mm which is within the limit
Reinforcement requirement:
X direction reinforcement:
Y direction reinforcement:
Conclusion:
Thus footing design is done using SAFE software.
Design of piles:
Aim:
To model , analyse and design the pilecap for the given data.
Procedure:
Column size - 60mm x 600mm
Axial load = 1175kN
Length of pile = 16m
Diameter of pile = 500mm
Loading capacity of one pile = 200kN
Calculation of number of piles:
Number of piles = Axial load/ capacity of each pile
= 1175/200 = 5.8
Therefore we need to provide 6 number of piles.
Spring stiffness = EA/L
E = 25000 N/`m^2`
Area of pile , A = 3.14 x `500^2` / 4 = 196349 `m^2`
Length of pile = 16m
Spring value = 306.8 kN/mm
Minimum spacing between the piles = 2.5 x diameter of pile
= 2.5 x 500 = 1250mm
Edge spacing = 200mm
Modelling in SAFE:
Open a new model and define the parameters
Define the material properties of steel and concrete.
For concrete M25 grade
Pilecap depth:
Define --> section properties ---> slab properties
Column definition:
Assigning Spring stiffness value :
Modelling of pilecap:
Load assigning and load combinations are done in the model.
Analysis:
Save the model and run the analysis,check for punching shear and design the pilecap.