Foundation Design using SAFE

QUESTION:1

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.

ANS:

AIM:

• To Analyze and designthe isolated footing from week 11 challenge on SAFE
• To verify the size, depth and steel provided as per calculations.

 

INTRODUCTION:

• CSI SAFE (Slab Analysis by the Finite Element Method) is the best tool for designing concrete slabs and foundations.
  
  
• SAFE provide easiness to engineer towards the safe design of structures with powerful tools like draw, analyze, design and detailing etc.
  
  
• Laying out models is quick and efficient way with the user-friendly drawing tools, or user can import model from AutoCAD or loading conditions from other software's like CSI ETABS and CSI SAP2000.

 

PROCEDURE:

STEP: 1

Open the SAFE Application 

select New Model

followed by Input Settings,

Units was selected as Metric and Code IS 456-2000.

STEP: 2

 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 X 5000
= 25000N/mm²

STEP: 3

 Define slab properties

• Define proterties for footing

• define properties for mat

• 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:

 HENCE, THE ISOLATED FOOTING WAS DESIGNED AMD ANALYIZED IN SAFE SUCCESSFULLY.

 

 

 

 

QUESTION: 2

A column of size 600x600 carrying an unfactored gravity load (DL+LL) of 1175 KN is to be supported on pile cap, which ultimately transfers load to the piles underneath. Piles of 16 metres length and 500 mm diameter are to be used. Each pile has a load carrying capacity of 200 KN. 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

 

ANS:

AIM:

• TO MODEL ANALYSI, 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
    

INTRODUCTION:

• CSI SAFE (Slab Analysis by the Finite Element Method) is the best tool for designing concrete slabs and foundations.
  
  
• SAFE provide easiness to engineer towards the safe design of structures with powerful tools like draw, analyze, design and detailing etc.
  
  
• Laying out models is quick and efficient way with the user-friendly drawing tools, or user can import model from AutoCAD or loading conditions from other software's like CSI ETABS and CSI SAP2000.

 

PROCEDURE:

GIVEN DATA:

 

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 X 5000
  = 25000N/mm²

• 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:

 Complete design of pile cap foundation using SAFE software.