Foundation Design using SAFE
Q:-1
Aim:-
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.
INTRODUCTION:
- CSI SAFE (Slab Analysis by the Finite Element Method) is the best tool for designing concrete slabs and foundations.
- SAFE provide easiness to engineers towards the safe design of structures with powerful tools like drawing, analyzing, designing and detailing, etc.
- Laying out models is a quick and efficient way with the user-friendly drawing tools, or the user can import models from AutoCAD or loading conditions from other software like CSI ETABS and CSI SAP2000.
PROCEDURE:
Open the SAFE Application
and select New Model followed by Input Settings,
Units were selected as Metric and Code IS 456-2000.
Subgrade modulus = (F.O.S x S.B.C) / Settelment.
= (3 x 150)/0.05
= 9000 KN/m ^ 3
The axial compression load for load combination = 1.5(D.L+L.L) = 2000 KN.
Unfactored load= 2000/3 = 1333.333KN
= 1333.33/2 = 666.5 KN
Footing thickness= 800 mm.
Define materials and add M25 Concrete.
- Add rebar/steel Fe500
Material Property data:
Click define followed by Material properties M25-grade of concrete Modulus of elasticity,
E = √25 X 5000
= 25000N/mm²
Define slab properties
- define properties for mat
- define properties for stiff
- Define Load pattern
- Assign point load
- Assign load combinations
- check design preference (min cover 50mm)
- run analysis and design
Result:-
Q:-2
Aim:-
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.
INTRODUCTION:
- CSI SAFE (Slab Analysis by the Finite Element Method) is the best tool for designing concrete slabs and foundations.
- SAFE provides easiness to engineering towards the safe design of structures with powerful tools like draw, analyzing, designing and detailing, etc.
- Laying out models is a quick and efficient way with the user-friendly drawing tools, or the user can import models from AutoCAD or loading conditions from 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.
50mm each was provided as cover at the top and bottom and the Bar size was defined as 16mm.
Coordinates were defined next.
Grid spacing in the X direction and Y direction was taken as 2.9m and 1.65m
respectively.
It's shown below figure too.
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.
Define 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
Create a column of 600mm x 600m
draw the column in the center using the quick draw tool.
Springs were added
select pile- assign -support data - point springs
The Springs constant is taken from the above calculation
Dead and Live Loads of 587.5KN are added next.
load case combination as defined next.
After defining the load combination run the analysis
max displacement was found to be .45
so it's safe
Also, all the Punching shear values are less than 1
so it's safe.
joint reaction diagram
as all the reaction forces are according to the limit,
it's safe.
Reinforcement details are added next as shown in both X and Y directions respectively and run the analysis again
Reinforcement slab design
Result:-
Complete design of pile cap foundation using SAFE software.
