Foundation Design using SAFE

1. AIM

• To analyze and design the 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 elemnet 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
• Lying 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 spftware,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

• single footing selected

Subgrade modulus =( Factor of safety * safe bearing capacity)/settlement = (3*150)/0.05

= 9000 KN/m^3

The compression axial load for the load combination ( 1.5DL+1.5LL) is 2000KN

Unfactored load = 2000/1.5 = 1333.3KN

1333.3/2= 666.65 KN

Footing thickness 800mm

STEP:2

Define materials

• Add M25 concrete

• Add rebar Fe500

Material propert data :

click define followed by material properties

M25 grade of concrete

Modulus of elasticity,

E= 25000 N/mm^2

STEP:3

Define slab properties

• Define properties 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 combinations

STEP:8

Check design preferences (min cover 50mm)

STEP:9

Run Analysis and Design

RESULT

Hence the isolated footing was designed and analysed in SAFE successfully

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2. AIM

• To 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

INTRODUCTION

• CSI SAFE ( slab analysis by the finite elemnet 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
• Lying 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 spftware,s like CSI ETABS and CSI SAP2000

PROCEDURE

STEP:1

Manual calculation

1. Column size:600*600mm
2. unfactored load :1175KN
3. Pile strength : 16m
4. Pile daimeter : 500mm
5. Load carriying capacity : 200KN
6. Number of piles : 1175/200 = 5.8 = 6
7. Spring constant :306795kN/m

E=5000*25^o.5 = 25000N/mm^2

A= Pi/4*500^2=196349mm^2

L=16m

Spring constant = 306795kN/m

Edge spacing = 200mm to 300mm

STEP:2

• Open the SAFE application

• Select new model,followed by input settings
• Units was selected as metric and code IS 456-2000

• Selected grid only

STEP:3

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= 25000 N/mm^2

STEP:3

Define slab properties

• Define pile cap

• Define column stiffness

• Define pile

STEP:4

Load cases and combinations

STEP:5

• Draw slab by using quick draw tool
• Draw points
• Add piles at the point
• Modify the edge distance to 0.3m
• create a column of 600mm*600mm
• Draw column in the center using the quick draw tool

STEP:6

• Springs were added
• Select pile-->assign-->support data-->point springs
• The spring constant is taken as the above calculation

STEP:7

Dead and live load of 587.5kN are added

STEP:8

Run the analysis

RESULT

Punching shear

Reaction forces

Pile cap foundation design

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