Foundation Design using SAFE

1)

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.

PROCEDURE:

• Open SAFE Application and click on New Model

• Select Metric units and Code as IS 456-2000.

Subgrade Modulus Calculation:

Subgrade modulus= F.O.SXS.B.C/Settlement

= 3x150/0.05

= 9000 `(Kn)/m^3`

Compression axial load for the load combination (1.5DL+1.5LL) is 2000KN.

Unfactored load= 2000/1.5

= 1333.3KN

1333.3/2 = 666.5KN

• Thickness of footing is 800mm.: Fill the values as obtained or as required.

• Now, select Define materials

• Add M25 Concrete in the material property

• Now, add rebar Fe500

• Material Property data:

Click define and then Material properties

Select M25 grade of concrete

Choose Modulus of elasticity as the value obtained below:

E=√25×5000

E=5×5000

= 25000 `N/(mm^2)`

• Now, define slab properties: Choose section properties and then slab sections

• Define properties for footing as shown below:

• Now, Define properties for mat

• Then, Define properties for stiff:

• Now, Define Load patterns

• Also, Define soil subgrade modulus as shown below:

• Assign point loads as shown below:

• Now, assign load combinations:

• Also, check design preference (min cover 50mm)

• Now, Run analysis and design

RESULT:

The Isolated Footing was designed and analysed in SAFE successfully.

2)

AIM:

To model, analyse and design the pile cap in SAFE to evaluate the following:

• Pile group to be used
• Depth of pile cap
• Longitudinal steel on top and bottom face in both directions

• Given Information:

Column Size = 600mmx600mm

Unfactored Load = 1175KN

Pile Length = 16m

Pile Diameter = 500mm

Load Carrying Capacity =200KN

• Calculations:

Number of Piles = 1175/200=5.8

Therefore no.of pillers = 6

Spring Constant = ExA/L

E = 25000 Nmm2">N/mm2

Area, A = 196349 mm2">mm2

Spring Length, L = 16000MM

Spring Constant = 25000x196349/16000

= 306795 N/mm

Edge Spacing is Taken as 200mm of 300mm

PROCEDURE:

• Open SAFE Application

• Select new model
• Then followed by input settings
• Metric Units were selected and Code is selected as IS 456-2000.

• 50mm each was provided as cover at top and bottom and Bar size was defined as 16mm

• Now, define the coordinates.

• Grid spacing in X direction was taken as 2.9m and Y direction was taken as 1.65m respectively.

• Choose the material property data as shownn below:

  • Click define then followed by Material properties
  • Select M25 grade of concrete

  • Also choose Modulus of elasticity as shown below,

    E=√25×5000

    E=5×5000

    = 25000 N/mm2

• Then add the Fe 500 Rebar next as shown below:

• Next, Define slab properties:

  • Define pile cap

• • Define column
• 
  • Define pile details
• 
• Draw the slab by using quick draw tool.

• Then draw points as shown below:

• Add piles at the points

• Create a column of 600mm x 600m

• Draw the columns in center using quick draw tool

• Springs are added here

• Select pile, then click on assign, select support data and choose point springs

• Dead and Live Load of 587.5KN are added next

• Load case combinations are defined next

• After defining the load combinations, run the analysis.

• Max displacement was found to be 0.84

• So it can be concluded as safe

• Also, all the Punching shear values are less than 1

• So it can be concluded as safe.

• Joint reaction diagram :

• As all the reaction forces are according to the limit, it can be concluded as safe

• Add the Reinforcement details next as shown in both X and Y direction respectively and also run the analysis again

• The Reinforcement slab design is as follows:

• Pile cap foundation design is as follows:

Result:

Design of pile cap foundation using SAFE software is successfully Completed.