building construction type of shallow foundation.

1. STEEL GRILLAGE
FONDATION
Presented By :
Name : Komal Prasad
Roll No : 1405003
Semester : 4th
Dept. of Architecture
N.I.T. PATNA

2. INTRODUCTION
 A Grillage foundation is a special type of isolated
footing, generally provided for heavily loaded steel
stanchions.
 It is a type of shallow foundation.
 It is used in the location where safe bearing capacity of
soil is very poor .
 Its name define its function and structure as it is made
up of steel beams, structurally known as rolled steel
joist.
 It may also be provided for masonry walls.

3. METHOD OF CONSTRUCTION
 The depth of foundation is limited from 1m to 1.5m
, as its a type of shallow foundation. However it
should not be less then 90 cm.
 Steel beams are provide in
two or more tiers, the top tier
of grillage beam is laid at right
angles to the bottom tier.
 The beam of each tier are
held in position by 20 mm
diameter spacer bars with
25 mm diameter pipe separators.

4. METHOD OF CONSTRUCTION
 The grillage beam are then embedded in concrete , a
minimum gap of 8cm is kept between beams so the
concrete can be easily poured and properly compacted.
 After levelling the base and pouring the concrete its
should be checked that compaction is done properly
and formed an impervious layer of thickness not less
than 15 cm. This protect steel joist from groundwater,
which can cause corrosion.
 Then the first layer of beams are laid over concrete bed
at a distance of 100mm to 300mm, with the help of
pipe separators.
 The upper surface of all the steel beams should lies in
one horizontal plane.

5. METHOD OF CONSTRUCTION
 Rich cement grout is poured all around the lower
flanges of the beam so that they are secured to the
concrete bed.
 Concrete is poured between and around the beams of
first of first tier.
 The second tier of beam is then placed at the right
angle to the first tiers and over the top flanges of the
beams of the first tier.
 They are properly spaced with the help of pipe
separators

6. METHOD OF CONSTRUCTION
 Concrete is then poured between and around the
steel beams.
 The steel stanchions is then connected to the upper
tier with the help of a base plate, side angles, and a
gusset plate.
 These connecting elements are also embedded in the
concrete so that joint become rigid.

7. PRECAUTION TO BE TAKEN
 The depth of footing should not be less than 90cm.
 The distance between the flanges should not exceed
30cm so that filled concrete acts monolithically with
the beams.
 The concrete filling should not carry any load ; its
simply keeps the beams in the position.
 A minimum gap of 10cm is kept on the outer side of
the external beam, as well as the upper flanges of top
tier.
 The depth of concrete below lower tier should be
atlest 15cm.

8. PLAN OF STEEL GRILLAGE

9. ELEVATION AND SECTION

10. VIEW OF ELEMENTS OF FOOTING

11. BIBLIOGRAPHY
 Book Building Construction by Dr. B.C. Punmia,
Ashok Kumar Jain and Arun Kumar Jain.
 Google ; Wikipedia
 Class work sheets.

12. THANK YOU