Foundation Design using SAFE
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.
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
AIM:
To Check the Model isolated footing provided Analyze and design it to verify the size, depth and steel provided as per calculations
DATA REQUIRED:
Unfactored load=2000/1.5=1333.3 KN
Dead load =1333.3/2=666.6 KN
Live Load =1333.3/2=666.6 KN
Subgrade modulus for soil=Safe bearing capacity x factor to ultimate / maximum settlement
=150 x 3 x 0.05=9000 KN/m3
Rebar yield strength (Fy)=500 N/mm2
Rebar ultimate strength (Fu)=575 N/mm2
Elastic modulus of concrete = 25000 N/mm2
PROCEDURE:
- First open the safe application and open the new model
- To check the unit as SI and click ok
- After that to open a single footing and enter the live and dead load as 666.5 and 666.5 simanteously
- After go for an define material add the concrete
- Once check the compression value
- Same for adding rebar
- After to click the slab section add footing , slab and stiff
- I have designed the height of the footing as 800mm and matt as 300mm
- Finally once ceck the material properties
- After that adding soil property
- And once the check the footing property
- After that adding point load as
- To click the load combination add the load combination
- After that to run the analysis the design
RESULT:
Finally we design and analyze the isolated footing
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 model an pile cap design and analyze
DATA REQUIRED:
Unfactored load =1175 KN
Dead load =1175/2=666.6 KN
Live Load =1175/2=666.6 KN
Area=3.14/4x500^2=196349
Point spring of pile = A x E /L
=196349 x 25000 / 16000
=306796 KN/m
K for safe analysis = 306.8 KN/mm
Rebar yield strength (Fy)=500 N/mm2
Rebar ultimate strength (Fu)=575 N/mm2
Elastic modulus of concrete = 25000 N/mm2
Coulmn Size = 600 x 600 mm
Pile length = 16m
Pile diameter = 500mm
Load carring capacity=200 KN
Number of piles=1175/200=5.8
We consider as the 6 pile
PROCEDURE:
- To Open the SAFE Application and select the new model
- To select the Units was selected as Metric and Code IS 456-2000.
- After that go for an design preference and choose 50mm each was provided as cover at top and bottom and Bar size was defined as 16mm
- 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.
- After that the to check the safe
- After that define option and go for an Material Property data and choose the concrete
- M25 grade of concrete
- Modulus of elasticity,
E = √25 X 5000
= 25000N/mm²
- And we next added rebar Fe 500 Rebar was added next as shown below
- Define slab properties and choose pile cap
- Add to the slab properties add column
- Add define pile details
- Draw the slab by using quick draw tool
- To draw the points in column
- Add piles at the point and modify the edge distance to 0.3m
- Create a column of 600mm x 600m draw the column in center using quick draw tool
- Springs were added select pile to choose assign choose support data choose point springs Springs constant is taken frome above calculation
- Dead and Live Load of 587.5KN are added next
- Load case combination was defined next.
- After defining the load combination run the analysismax 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
- Reinforcement slab design:
- pile cap foundation design
RESULT:
Complete design of pile cap foundation using SAFE software.
