Foundation Design using SAFE

TASK 1: Model the isolated footing provided in the week 11 challenge on SAFE. Analyze and design it to verify the size, depth, and steel provided as per calculations.

AIM:

• To analyze and design the isolated footing from the 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 provides easiness to engineer towards the safe design of structures with powerful tools like draw, analyze, design and detailing, etc.
• Laying out models is the quick and efficient way with the user-friendly drawing tools or users can import models from AutoCAD or loading conditions from the other software like CSI ETABS and CSI SAP2000.

PROCEDURE:

Open the SAFE Application

Select New Model

Followed by Input Settings,

Units were selected as Metric and Code IS:456-2000.

Single Footing was selected next

Subgrade Modulus = (F.O.S x S.B.C)/ Settlement = `(3xx150)/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=666.5KN`

Footing thickness 800mm

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 = `sqrt25xx5000=25000N/(mm^2)`

Next, Define slab properties

Define properties for footing

Define properties for Mat

Define properties for stiff

Define Load pattern

Define soil subgrade modulus

Assign Soil Subgrade data

Assign point load

Assign load combinations

Check design preference (Min cover 50mm). check the model and Run analysis and Design

RESULT:

Hence, The Isolated Footing was designed and analyzed using SAFE successfully. The results of each drawing drawn in SAFE are attached.

TASK 2: A column of size 600x600 carrying an unfactored gravity load (DL+LL) of 1175 KN is to be supported on a pile cap, which ultimately transfers the load to the piles underneath. Piles of 16 meters length and 500 mm diameter are to be used. Each pile has a load-carrying capacity of 200 KN. Model, analyze 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

AIM:

• To model analyze 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 provides easiness to engineer towards the safe design of structures with powerful tools like draw, analyze, design and detailing, etc.
• Laying out models is the quick and efficient way with the user-friendly drawing tools or users can import models from AutoCAD or loading conditions from the other software like CSI ETABS and CSI SAP2000.

PROCEDURE:

Given Data:

Column Size:- 600X600

Unfactored load:- 1175KN

Pile length:- 16m

Pile Diameter:- 500mm

Load carrying Capacity:- 200KN

Calculations:

Number of pilers:- `1175/200=5.8=6`

Spring Constant:- `(ExxA)/L`

where E is:- `25000N/(mm^2)`

Area (A) is:- `pi/4xx500^2=196349mm^2`

Pile Length, L is:- 16000mm

Spring Constant:- `(ExxA)/L=(25000xx196349)/16000=306795N/(mm)`

Edge spacing is taken as 200mm or 300mm.

Open the SAFE Application.

Select New Model

Followed by input settings.

Units were selected as Metric and code IS:456-2000.

Co-ordinates were defined next.

Grid spacing in the X direction and y direction was taken as 2.9m and 1.65m respectively.

Material Property data:

Click define followed by material properties

M25 grade of concrete

Modulus of elasticity,

E = `sqrt25xx5000=25000N/(mm^2)`

Fe 500 Rebar was added next.

Define the Slab Properties

Define Pile cap

Define Column

Define Pile Details

Draw the slab by using the quick draw tool

Draw points

Add piles at the point

Modify the edge distance to 0.3m

Create a column of 600mm X 600mm

Draw the column in the center using the quick draw tool.

Springs were added

Select pile, then assign, then support data, then point springs.

Springs constant is taken from the above calculation.

Next, Add Dead and live load of 587.5KN

Define Load Case Combination

After defining the load combination run the analysis

max displacement was found to be 0.84. So, It is Safe.

All the Punching Shear values are less than 1. So, It is Safe.

Joint Rection Diagram

As All the reaction forces are according to the limit. So, It is safe.

Reinforcement details are added next as shown in both X and Y direction respectively and Run the analysis again.

Reinforcement Slab Design:

Pile Cap Foundation Design:

RESULT:

Hence, Completed the design of the pile cap foundation using SAFE Software. The results of each drawing drawn in SAFE are attached.