Foundation Design using SAFE

Q.1 Ans

Aim: Model the isolated footing provided in week 11 challenge on SAFE. Analyze and design it to verify the size, depth and steel provided as per calculations.

Procedure:

Step 1: 

a. Open the SAFE software.

b. Create new file. Provide the unit as Matric SI, IS codes and Ok.

c. Select the single footing and add the given below by calculation.

i. Safe bearing capacity= `150 kN//m^2`

ii. F.O.S = 3

iii. Settlement = `50mm`

`Subgra de soil = (F.O.S xx S.B.C)/(Set t l e ment)`

                       `= (3 xx 150)/0.05`

                        `= 9000 kN//m^3`

`therefore` The compression axial load for the load combination of `(1.5DL+1.5LL)`is `2000kN`.

`therefore`Unfactored Load = `2000/1.5`

                                         = `1333.33 kN`

`therefore` DL will be = `1333.33/2`

                                 = `666.65 kN`

`therefore` LL will be =`1333.33/2`

                                 = `666.65 kN`

The thickness of footing is 800mm.

Step 2:

a. Add material properties 

Go to Define -> Material Properties 

i. Create a material property for concrete of M25 Grade. Add the data as shown below.

b. Add material properties 

Go to Define -> Material Properties 

i. Create a material property for Rebar of Fe500 Grade of Steel. Add the data as shown below.

Step 3:

a. Add section properties for Slab, MAT, Footing & Stiff from slab section.

Go to Define -> Section Properties -> Slab Section. 

b. Go to Define -> Spring properties -> Area Spring.

Add the data given below.

Right click on the footing & change the spring to soil.

c. Define the load patterns.

Step 4:

a. Go to draw -> Draw joint and add the joints at the centre.

b. Select the point & assign joint loads for dead load and live load.

c. Add the load combinations & then run analysis.

Result:

a.Deformed shape of footing. 

b. Deformed shape due to drift shear.

c. Strip forces due to Dead load & Live load.

d. Punching Shear values.

All the values and deformed shape is safe.