Foundation Design using SAFE
Solution:
Aim:
- To Analyze and design the isolated footing from week 11 challenge on SAFE and verify the size, depth and steel provided as per calculations.
STEP: 1
1.Open the SAFE Application and select New Model
2.Units was selected as Metric and Code IS 456-2000.
Subgrade Modulus Calculation:
Subgrade modulus=F.O.SXS.B.C/Settlement
= 3x150/0.05
= 9000 `(kN)/m^3`
The compression axial load for the load combination (1.5DL+1.5LL) is 2000KN.
Unfacrtored load=2000/1.5
= 1333.3KN
1333.3/2=666.5KN
3.Thickness of footing is 800mm.
STEP: 2
1.Open Define materials
Add M25 Concrete
Add rebar Fe500
Material Property data:
Click define followed by Material properties
M25 grade of concrete
Modulus of elasticity,
E=√25×5000
E=5×5000
= 25000 `N/(mm^2)`
STEP: 3
1. Define slab properties
2.Define proterties for footing
3.Define properties for mat
4.Define properties for stiff
STEP: 4
Define Load pattern
STEP: 5
Define soil subgrade modulus
STEP: 6
Assign point load
STEP: 7
Assign load combinamtions
STEP: 8
check design preference (min cover 50mm)
STEP: 9
Run analysis and design
RESULT:
The Isolated Footing was desinged and analysed in SAFE is successfully.
Solution.2)
Aim:
To Model, analyse and design the pile cap on SAFE to evaluate the following,
- Pile group to be used
- Depth of pile cap
- Longitudinal steel on top and bottom face in both directions
Solution:
Given Data:
Column Size = 600mmx600mm
Unfactored Load = 1175KN
Pile Length = 16m
Pile Diameter = 500mm
Load Carrying Capacity =200KN
Calculation:
Mumber of Pilees = 1175/200=5.8
Therefore no.of pillers =6
Spring Constant = ExA/L
E = 25000 `N/(mm^2)`
Area, A = 196349 `mm^2`
Spring Length, L = 16000MM
Spring Constant = 25000x196349/16000
= 306795 N/mm
Edge Spacing is Taken as 200mm of 300mm
Step 1:
Open the SAFE Application
select New Model
followed by Input Settings,
Units was selected as Metric and Code IS 456-2000.
50mm each was provided as cover at top and bottom and Bar size was defined as 16mm
Step 2:
Coordinates was defined next.
Grid spacing in X direction and Y direction was taken as 2.9m and 1.65m
respectively.
It's shown in the below figure too.
Step 3:
Material Property data:
- Click define followed by Material properties
- M25 grade of concrete
-
Modulus of elasticity,
E=√25×5000
E=5×5000
= 25000 `N/(mm^2)`
- Fe 500 Rebar was added next as shown below
Step 4:
Define slab properties
- define pile cap
- define column
- define pile details
Step 5:
Draw the slab by using quick draw tool
draw points
Step 6:
Add piles at the point
modify the edge distance to 0.3m
Step 7:
Create a column of 600mm x 600m
draw the column in center using quick draw tool
Step 8:
Springs were added
select pile< assign < support data < point springs
Springs constant is taken frome above calculation
Dead and Live Load of 587.5KN are added next
Step 9:
Load case combination was defined next.
After defining the load combination run the analysis
max displacment was found to be .84
so its safe
Also, all the Punching shear values are less than 1
so its safe.
joint reaction diagram
as all the reaction forces are according to the limit,
its safe
Reinforcement details are added next as shown in both X and Y direction respectively and run the analysis again
Step 10:
Reinforcement slab design:
pile cap foundation design
Result:
Successfully Completed the design of pile cap foundation using SAFE software.
