Foundation Design using SAFE
1. Aim: To Model the isolated footing provided in the week 11 challenge on SAFE and Analyze and design it to verify the size, depth, and steel provided as per calculations.
Procedure:
- Open SAFE software.
- Go to the new model And specify the units.
- Now select single footing.
- Subgrade modulus = FOSxSBC/settlement.
- Soil safe bearing capacity = 150 kn/mm^2
- FOS = 3
- Settlement = 25mm
- Subgrade modulus = 3x150/0.025 = 18000.
- The compression axial load for the load combination of (1.5 DL + 1.5 LL) is 2000 KN.
- Unfactored load = 2000/1.5=1333.33
- 1333.33/2 = 666.65KN.
- Square footing for a column size of 400 x 400.
- The thickness of the concrete footing to be 460mm.
- The size of the footing slab is 3.2x3.2m
- Go to define tab
- And click on the material property.
- Then add the material property
- M25 as concrete and Fe500 as steel.
- Again Go to the define tab
- And click on the Slab property.
- Then add the Slab property of thickness 460mm.
- Again Go to the define tab
- And click on the soil subgrade property.
- Assign the soil for footing.
- And load on center of the column od dead load
- Give the load combinations
- Now check the model.
- If there is no errors then run the analysis.
- The punching shear should be less than 1
- Then increase the thickness of the footing.
- After increasing the thickness the punching shear decreases.
- Then unlock the model
- Draw the stirps in layer A and B.
- The run the analysis
- Go to the display tab and select show slab design.
Result:
Therefore isolated footing is designed by using SAFE software.
2. Aim: To design the pile cap on safe and to evaluate pile group to be used, depth of the pile cap and longitudinal steel on top and bottom face in both directions.
Procedure:
- Column size = 600x600
- Un factored load = 1175 KN
- Piles, L=16m, d=500mm, Loading capacity=200KN
- No,of piles = 1175/200 = 5.8= 6
- Spring constant =E*AlL
- Where, E = 25000n/mm^2
- A = pi/4 X 500^2 = 196349mm^2
- L=16000mm
- Minimum spacing = 2.5x diameter = 2.5x500=1250mm
- Edge spacing = 200mm
- Open SAFE software
- click on new model and specify the units.
- Select the grid option
- In X-direction = 3.4m
- In Y-direction = 2.15m
- Go to define tab
- And click on the material property.
- Then add the material property.
- M25 as concrete and Fe500 as steel.
- Again Go to the define tab
- And click on the Slab property.
- And Give the thickness of 800mm.
- Again Go to the define tab
- And click on the soil subgrade property.
- Go to the Assign tab
- And select point springs
- Assign the dead load to column
- Go to define tab
- And click on load combinations
- Give the combinations and run it
- Check the model and run the analysis
- Punching shear force
- Then unlock the model
- Draw the stirps in layers A and B.
- Go to the display tab and select show slab design.
Result:
Completed the designing of pile foundation in SAFE software.