Week 12 Challenge

1.

• Given - 
• Column = 300 mm x 450 mm.
• Axial load = 1500 kN
• Mu = 150 kNm.
• Assume that the moment is reversible.
• The safe bearing capacity of the soil = 200 KN/m^2.
• Depth = 1 m from ground level.
• M 25 and Fe 415 for the footing

Procedure: Open staad foundation -> Click on general mode -> Foundation plan -> Linear grid setup.

Go column position -> Enter value or click on origin (0,0,0) -> Column dimensions -> Pedestal and anchor bolt-> yes put as length = 1 m, width = 1 m, height = 1 m. 

Go to loads and factors -> Create new load case -> Add column reaction load -> Assign to column.

Axial load = P = 1500 KN.

So Pu = ultimate axial load = 1500 x 1.5 = 2250 KN.

So 1.5 as partial safty factor as per IS 456:2000.

Mu = 150 KNm.

Go generate load combinations -> Choose indian -> Generate it.

Go soil properties -> Choose Bearing capacity factors -> Create new job -> Define all design parameters.

Check design -> Footing is safe our values entered is correct.

Validation by hand calculation.

Calculation snaps are attached and all are correct as per validation.

 2.

Aim - To design Combined footing with given data.

Given - 

Two columns C1 = 400 mm x 400 mm.

Service load = 800 kN.

C2 = 300 mm x 500 mm.

Service load = 1200 kN.

The column C1 is flushed with the property line.

The columns are at 3.0 m c/c distance.

The safe bearing capacity of soil is 200 KN/m^2 at a depth of 1.5 m below the ground level.

Use M 20 and Fe 415 for columns and footing.

Procedure:

Open staad foundation -> Click on general mode -> Foundation plan -> Linear grid setup.

Go to column position -> Column dimension as per given -> Add pedestal and anchor bolt. 

Create new load case -> Add column reaction -> Assign load for columns.

For column c1 service load = 800 KN.

For column c2 service load = 1200 KN.

Generate load combination -> add indian load combinations.

Create new job -> Combined footing -> Choose indian. -> Select column edit current job -> Click strip footing setup

Click create from selected nodes

Go to design parameters -> Add cover and reinforcement -> Add cover and soil -> Add footing geometry

Add sliding and overturning factors.

Go to design -> Click design save ok.