Foundation Design using SAFE
1.
AIM :
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.
square footing for column size of 400x400
compression axial load for the load combination of (1.5DL + 1.5LL) is 2000KN
the safe soil bearing capacity is 150kn/m.sq at a depth of 2metre below E.G.L.
assume M25 concrete grade
INTRODUCTION :
- CSI SAFE (slab analysis by finite element method) is the best tool for designing concrete slab and foundations
PROCEDURE :
- open the SAFE application
- select new model
- select the units and design codes
- single footig was selected next
subgrade modulus = F.O.S X S.B.C / SETTELEMENT
where, FOS for soil is =3
S.B.C = 150Kn/m.sq
settelement for isolated footing = 25mm
hence, subgrade modulus = 18000kn/m.sq
the compression axial load for the load combination (1.5DL + 1.5LL) is 2000Kn
Unfactored load = 2000/1.5= 1333.6kn
live load = 1333.3/2= 666.5 kn
dead load = 1333.3/2=66.5kn
footing thickness 600mm
column load size = 400x400 mm
1. define material properties :
- go to the define tab and select material property
- add M25 concrete
add new property as rebar
2.define section property
- next, define section property
- go to slab property
- add mat > thick shell > mat type > 600mm thicknes
add next stiff property
change the type as stiff
3.defining load pattern( dead load and live load)
anayze the data - run analysis
RESULT :
we have Modeled the isolated footing provided in week 11 challenge on 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 :
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 finite element method) is the best tool for designing concrete slab and foundations
PROCEDURE :
given data,
column size = 600x600mm
unfactored load = 1175 kn
pile length =16m
pile diameter= 500mm
load carrying capacity= 200kn
calculations :
number of piles = 1175/200=5.8
therefore no. of pillars = 6
spring constant = E X A/L
= 25000n/mm.sq
area A = ∏/4 x (500)^2
=196349mm.sq
spring length, L = 16000mm
= 25000 x 196349/16000
= 306795 n/mm
edge spacing taken as 200mm of 300mm
step-1:
- open the safe application
- select new model
- followed by input setting
- units was selected as metric and code IS 456:2000
- 50mm each provded as cover at top and bottom and bar size was defined as 16mm
step-2 :
coordinate was defined next '
grid spacing in x direction and y directionn take as 2.9 and 1.65 m respectively
step-3
material property data :
click define > material property
M25 grade of concrete
modulas of elasticity = √25 x 500 = 25000n/mm^2
fe500 rebar was added
step-4:
define slab properies
define pile cap
define column
define pile details
draw the slab by using quick draw tool
draw points
step-6:
add piles at point
modify edge distance to 0.3m
step-7 :
create a column of 600x 600m
draw the column in center using quick draw tool
step-8 :
springs were added
select pile > assign > support data > point springs
springs constant taken from above calculations
dead and live load of 587.5kn are added next
step-9 :
load case combination defined next
run the analysis
max displacement was found to br 0.84
so its safe
all the punching shear value are less than 1
so its safe
joint reaction diagram
as all the reaction forces are according to 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 :
successfully design the pile cap foundation using safe software
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