Foundation Design using SAFE

Aim

• o Analyze and designthe 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 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.

procedure

step1

open the safe application

select new model

followed by Input Settings,

Units was selected as Metric and Code IS 456-2000.

single footing wass select

sub grade modulus for soil =safe bearing capacityx facctor to ultimate/max settlement

150x3/0.005

k=9000kn/m3

the compression axial load for the load combination (1.5D.L+1.5LL)

=2000KN

UNFACCTORED LOAD=2000/1.5=1333.3kn

1333.3/2=666.7kn

footing thickness=800

step2 define materials

add m25 concrete

MATERIAL PROPERTY DESIGN data

add rebar fe 500

add material property data

material property design data

Material Property data:

Click define followed by Material properties

M25 grade of concrete

Modulus of elasticity,
E = √25 X 5000
= 25000N/mm²

define slab property

define properrty of footing

deffine property of mat1

define properrty of stiff1

DEFINE LOAD PATTERN

define sub grade soil

assign load cases

step 6) load combination

go to define

and click on the load combination

run analysis

draw design strip

step 9)
check
safe bearing capacity
from reaction

punching shear design

strip forces

flexural reinforcement

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 o
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 direction

aim to deisgn a pile foundation usig safe software

ata required
unfactored load = 1175KN
dead load breakup = 1175/2 = 587.5 KN
Live load breakup = 1175/2 = 587.2

hence it is ok for safe analysis 306.8kn/m

Rebar yeild strength (FY) = 500N/mm^2
rebar ultimate strength = 575 N/mm^2
Elastic modulus of M25 concrete = 25000N/mm^2
number of piles required = unfactored load with self weight addition / indivisual pile
capacity
= 1175 X 1.1/200 = 6.5
consider 8 piles
take center to center distance between piles = 3 X piles diameter = (1500 mm)
Edge distance from pile center = 1 X pile dimeter = (500mm)
Assume pile cap depth = 500mm

tep 2)
safe design
open new model
and put all required information

3

material properties

click on material property from define

add m25 grade concrete from material

material property data

slab section

draw slab

draw the slab quick draw tool bar

draw refrence point
where we loacate the pile by the help of draw refrence point and replicate option from edit

add the pile
add the piles at the point
draw the pile by using quick draw area around pint
set dia as 500mm
and draw by cursor

now go to draw
then support data and point spring

add load
assign load to column
simply select the column point
go to assign
go to joint load
and then select garvity dead and live load are 587.5 kn

check design preferences

run the analysis

check for rection
check base rection for unfactored load
when we design for steel we need to check for factored load

design strip
to know the area of steel required
go to edit option
and click on add design strip

so strip is assign for X and Y direction
check width of strip
from display option

define load combination

again run the analysis
and check the r/f required
go to display option then slab design
and strip A press apply

and for strip B for y direction steel

and also done all check satisfy
and get quantity of steel required