Nabin Kumar Ijam | Civil & Hydropower Engineer

DESIGN OF FLAT SLAB AS PER BS 8110: 1997

INPUTS

Grade of Concrete (\(f_{cu}\) in MPa):

Grade of Steel (\(f_y\) in MPa):

Effective cover (\(c\) in mm):

GEOMETRY

Long span (\(L_1\) in m):

Short span (\(L_2\) in m):

Depth of slab (\(D_s\) in mm):

Long dimension of column (\(b\) in mm):

Short dimension of column (\(d\) in mm):

LOADS

Dead load (\(DL\) in kN/m²):

Live load (\(LL\) in kN/m²):

Provision of drop (YES or NO):

If Yes Drop Type (1 or 2):

Drop width shall be provided after calculation of minimum drop.

Width of drop (\(l_{ho}\) in m):

Thickness of drop (\(d_{h}\) in m):

INPUT VALUES FOR REINFORCEMENT DESIGN

depth of slab (\(d_{sl}\) in mm):

Input moment (\(M\) in kNm):

Diameter of reinforcement (\(\phi\) in mm):

Spacing of reinforcement (\(s\) in mm):

Flat Slab Diagram

DESIGN RESULT

1.DROP IF PROVIDED

Minimum width of drop(\(l_{min}\)) m

Ignorance of drop:

Width of Column strip: m

2. COLUMN HEADS (Clause 3.7.1.3)

Length of Column head (\(l_h\)): m

Effective diameter of column head: m

3. DIVISION OF PANEL

3.1 Column strip m

3.2 Middle strip

Long direction (\(l_{x1}\)): m

Short direction (\(l_{y1}\)): m

4. CALCULATION OF MOMENTS

4.1 MOMENTS (kNm)

Moments		x-direction	y-direction	Clause
Negative moments
Reduction of support moment	Internal support			3.7.2.7 d)
Reduction of support moment	External Support			3.7.2.7 d)
Design moment at support	Outer support			3.7.2.7 d)
	First interior support			3.7.2.7 d)
	Interior support			3.7.2.7 d)
Positive moments
Design moment at support	Outer support			3.7.2.7 d)
Design moment at support	Middle Interior support			3.7.2.7 d)

4.2 DISTRIBUTION OF DESIGN MOMENTS IN PANELS OF FLAT SLAB

Position	Column strip		Mid strip
Position	Total moment	Mt/width	Total moment	Mt/width
Negative moment
X-direction
Internal support
External support
Outer support
Y-direction
Internal support
External support
Outer support
Positive moment
X-direction
Mid of end span
Mid of interior span
Y-direction
Mid of end span
Mid of interior span

5. REINFORCEMENT DESIGN

Area of reinforcement (\(A_{st}\)): mm²

Area of reinforcement (\(A_{stp}\)): mm²