2. What Is FLATE PLATES
FLATE PLATES:
Flat Plates are concrete slabs
which are carried directly by
columns, without the use of
beams or girders..
Uses :
Commonly used where spans
are not large (20 to 25 ft).
& also loads not particularly
heavy (60 to 100 Psf)
3. DIFFERENCE BETWEEN
TWO WAY & FLAT PLATE
TWO WAY SLAB:
Slabs are resting on T-Beams.
Slab load transfer to the beams and then in to the
columns.
FLAT PLATE SLAB :
load is directly transferred to the columns
the shear is very critical at the area of
connection of slab with column (called punching
shear).
4. LITTLE CONFUSION REGARDING
FLAT PLATE & FLAT SLAB!!!!!!!!!!!!!
The flat plat is a slab of uniform thickness while in flat
slab there is thickened slab region in the vicinity of the
column that includes either drop panel or column
capitals.
Figure: Drop Panel & Column Head
5. ENSURE THAT:
Reinforcement bars
should be properly
detailed between the
columns and slabs.
Punching shear checks
are critical & vertical
shear reinforcement
should be detailed
accordingly.
6. Analysis (Moment Determination):
1.
A method of frame analysis such as
moment distribution, or stiffness
method or a Computer.
2. A simplified method using the
moment & shear co-efficient Table.
7. STEPS OF FLAT PLATE SLAB DESIGN
DETERMINE THICKNESS
DEAD & LIVE LOAD CALCULATION
MOMENT CALCULATION BY USING
TABLS & CO-EFFICIENTS
REINFORCEMENT DESIGN
SHEAR CHECK
8.
9.
10. Figure: Design Moment &
Shears for flat plate floor
interior Panel C.
(a): Moments
(b): Shears
11.
Another Important Aspect regarding flat
plate design is punching shear at the
columns which require supplementary
shear reinforcement, & transfer of
unbalanced moments to the column which
may require additional flexural bars in the
negative bending region of the column
strip
12.
13.
ADVANTAGES:
The simplified Formwork.
Reducing the Story Height which makes it Economical.
There are no beams to obstruct light & circulation of air.
Less danger of concrete spalling & exposing reinforcement.
LIMITATIONS:
Loads due to higher thickness of plate elements as required to control
deflection
Stiffness & weight consideration in earthquake areas
