Foundation Design using SAFE

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

AIM:

• To Analyse and model Isolated footing as per calculations by using SAFE.

PROCEDURE:

• Open safe software
• New model > input settings > metric units > IS 456-2000

SELECT Single footing

 

 

MATERIAL PROPERTIES:

Modulus of elasticity:  25x5000=25000N/mm^2

ADD REBAR:

SLAB PROPERTY:

 

SOIL SUBGRADE PROPERTY

ASSIGN SOIL PROPERTY:

• Right click on footing to get the properties

ASSIGN LOADS :

• Draw> draw points and then assign loads dead and live

 

ASSIGN LOAD COMBINATIONS:

RUN THE ANALYSIS:

• As it is less than 50mm it is expected

 

• Add design strips 
• Run the analysis and show slab designs
• Slab design

 

PUNCHING SHEAR CAPACITY:

RESULT:

• Isolated footing is designed using SAFE.

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

AIM:

• To design the pile cap on safe and to evaluate pile group to be used, depth of the pile cap, longitudinal steel on top and bottom face in both directions.

PROCEDURE:

 

 SELECT GRID OPTION

• x direction of distance 2900mm
• y direction of distance 1650mm

 

 Add materials:

 

 SLAB PROPERTIES:

• Add slabs to the model
• Draw points

 

 ADD PILES:

• Modified edge distance to 300mm as 200mm is not possible in placing piles of size 500mm

• Draw column of size 600x600 at the centre

 ADD SPRINGS:

• ..> assign....>support data....> point springs
• spring constant=EA/L

=306.795KN/mm

 NOW THE LOAD ARE ADDED 

• Dead load=587.5KN
• Live load=587.5KN

 

 RUN THE ANALYSIS:

 PUNCHING SHEAR CAPACITY RATIOS:

• In case of punching shear all values are less than 1, hence safe

 JOINT REACTION DIAGRAM:

• Reactions forces are according to the limit hence safe
• Reinforcement detailing is done
• Run the analysis once again
• Reinforcement slab design

RESULT:

• Completed design of pile cap foundation using SAFE software.