SLAB DESIGN CALCULATIONS

Project Name

:

a

Client Name

:

a

Engineer Name

:

a

Design File

:

D:\Bentley\000 RCDC 2010\11.1.0\Validation Problem\RCDC Files\slab design.rcdx

Analysis File

:

D:\Bentley\000 RCDC 2010\11.1.0\Standard model for Demo\Staad\RCDC-Staad-Demo -with RCC wall.std

Analysis Last Modified

:

3/17/2021 4:34:09 PM

 

 

 

NOTES:

1.

Slab is designed as per 1 M width of panel.

2.

Density of concrete assumed as 25 kN/Cum.

3.

Maximum spacing of Main steel is smaller of (2 x Deff and 300 mm)

4.

Maximum spacing of Distribution steel is smaller of (5 x Deff and 450 mm)

 

Definitions Of Terms: :

1.

α

=

Short Span and Long Span Coefficient for One Way Slab

2.

α2

=

Coefficient for Compressive Stress Block

3.

β

=

Short Span and Long Span Coefficient for Two Way Slab

4.

εx

=

Longitudinal Strain in the Concrete at the Mid Depth Of The Section

5.

γ

=

Ratio of Depth of the assumed rectangular stress block to kud

6.

γs

=

Short Term Factor as per AS 1170 Table 4.1

7.

γl

=

Long Term Factor as per AS 1170 Table 4.1

8.

φ

=

Capacity Reduction Factor

9.

acr

=

Distance from the point considered to the surface of the nearest longitudinal bar

10.

D

=

Overall depth of slab in mm

11.

Deff

=

Effective depth of slab in mm

12.

dv

=

Effective Shear depth in mm

13.

do

=

Distance from Extreme Compressive fibre to Centroid of Tensile Reinforcement

14.

dn

=

Depth to Neutral Axis

15.

Ec

=

Modulus of Elasticity of Concrete due to creep in N/sqmm

16.

Es

=

Modulus of Elasticity of Steel

17.

f'c

=

Characteristic Cylinder strength of concrete in N/sqmm

18.

f'ctf

=

Characteristic Flexural Tensile strength of concrete

19.

Fcv

=

Concrete Shear Strength

20.

Fd.ef

=

Effective Design Service Load per Unit Area

21.

Fsy

=

Yield Stress of Steel in N/sqmm

22.

Kcs

=

Factors Used in Serviceability Design to Take Account of the Long-Term Effects of Creep and Shrinkage

23.

kuo

=

Ratio of Depth to Neutral Axis from extreme Compressive fibre; at ultimate strength

24.

Ku

=

Neutral Axis Parameter being the Ratio, at Ultimate Strength Under any Combination of Bending and Compression, of the Depth to the Neutral Axis from Extreme Compression fibre to D

25.

Kv

=

Coefficient used for Allowable Shear

26.

K3

=

Deflection Constant

27.

K4

=

Deflection Constant

28.

Lef

=

Effective Span

29.

Ln

=

Clear Span

30.

M*

=

Factored Bending moment in kNm

31.

Sp

=

Spacing Between bars at outer most layer

32.

Vc

=

Permissible Shear in concrete in kN

33.

V*

=

Design Shear Force at a Cross-section

34.

Z

=

Section Modulus of Uncracked Cross Section

35.

Wcr

=

Surface Crack Width

 


 

Code References :

AS 3600 : 2018

 

 

ELEMENT

 

CLAUSE / TABLE

1.

Factored Load Fd

:

AS1170 4.2.2 (b)

2.

F'ctf

:

3.1.1.3

3.

α2

:

8.1.3 (1)

4.

γ

:

8.1.3 (2)

5.

Ast min

:

9.1.1

6.

Total Deflection

:

9.4.4.1

7.

Deflection Constant k4

:

Table 9.4.4.2

8.

Moment Coefficient for Two way slab

:

Table 6.10.3.2 (A)

9.

Allowable Shear

:

8.2.4.1

10.

Shear Coefficient Factor

:

6.10.2.4

11.

Ultimate Strength in Bending

:

8.1.6.1

12.

Effective Shear Depth

:

8.2.1.9

13.

Kv, θv

:

8.2.4.3


    

Slab No. :

S6

Level

=

7.858 m

Design Code

=

AS 3600 : 2018

Grade Of Concrete

=

N20

Grade Of Steel

=

500N

Clear Cover

=

20.000

mm

Long Span, Ly

=

8.900

m

Short Span, Lx

=

8.000

m

Imposed Load

=

2.000

kN/sqm

Live Load

=

3.000

kN/sqm

Slab Thickness

=

295.000

mm

Effective Depth Along LX, Deffx

=

270.000

mm

Effective Depth Along LY, Deffy

=

260.000

mm

Self Weight

=

7.380

kN/sqm

Total Load, Fd

=

15.750

kN/sqm

Span

=

2-Way

Panel Type

=

Interior Panel

Load Combination

=

1.2 DL + 1.5 LL

 

Design Moments:

Short Span Positive Moment At Midspan -

Moment Coefficient, M1

=

0.029

M* = M1 x Fd x Lx x Lx

=

28.728

kNm

Area Of Reinforcement Required (M*)

=

328.650

sqmm/m

Reinforcement Provided

=

N10 @ 235 C/C

 

=

334.000

sqmm/m

Short Span Negative Moment At Continuous Support -

Moment Coefficient, M2

=

0.038

M* = M2 x Fd x Lx x Lx

=

38.208

kNm

Area Of Reinforcement Required (M*)

=

339.480

sqmm/m

Reinforcement Provided

=

N10 @ 230 C/C

 

=

341.000

sqmm/m

Short Span Negative Moment At Dis-Continuous Support -

Moment Coefficient, M5

=

N.A.

M* = M5 x Fd x Lx x Lx

=

N.A.

kNm

Area Of Reinforcement Required (M*)

=

N.A.

sqmm/m

Reinforcement Provided

=

N10 @ 240 C/C

 

=

327.000

sqmm/m

Long Span Positive Moment At Midspan -

Moment Coefficient, M3

=

0.024

M* = M3 x Fd x Lx x Lx

=

24.192

kNm

Area Of Reinforcement Required (M*)

=

328.650

sqmm/m

Area Of Reinforcement Required (M* + Defl.)

=

341.290

sqmm/m

Reinforcement Provided

=

N10 @ 230 C/C

 

=

341.000

sqmm/m

Long Span Negative Moment At Continuous Support -

Moment Coefficient, M4

=

0.032

M* = M4 x Fd x Lx x Lx

=

32.175

kNm

Area Of Reinforcement Required (M*)

=

341.290

sqmm/m

Reinforcement Provided

=

N10 @ 230 C/C

 

=

341.000

sqmm/m

Long Span Negative Moment At Dis-Continuous Support -

Moment Coefficient, M6

=

N.A.

M* = M6 x Fd x Lx x Lx

=

N.A.

kNm

Area Of Reinforcement Required (M*)

=

N.A.

sqmm/m

Reinforcement Provided

=

N10 @ 240 C/C

 

=

327.000

sqmm/m

Distribution Reinforcement @ 0.12% -

Area Of Reinforcement Required

=

324.000

sqmm/m

Reinforcement Provided

=

N10 @ 240 C/C

=

327.000

sqmm/m

Shear Check :

Total Load from Triangular Area

=

252.000

kN

Average UDL from Triangular Area (L1)

=

31.500

kN/m

Total Load from Trapezoidal Area

=

869.400

kN

Average UDL from Trapezoidal Area (L2)

=

34.685

kN/m

Shear Check Along Short Span Continuous Support

Vx* = 1.0 x L1

=

31.500

kN

φVc

=

105.684

kN

 

> 

31.500

Slab Is Safe In Shear

Shear Check Along Long Span Continuous Support

Vy* = 1.0 x L2

=

34.685

kN

φVc

=

108.558

kN

 

> 

34.690

Slab Is Safe In Shear

Deflection Check:

Allowable Deflection = k3 k4(D/Lef)1000 Ec)/(Fd.ef)]1/3

Lef

=

8000.000

mm

Ec-mean

=

23713.555

F'def = (1+kcs)DL + (kcs x Ψl)LL

=

32.625

Δ/Lef

=

0.004

K3

=

1.000

K4

=

2.100

Ψs

=

0.700

Ψl

=

0.400

Allowable Deflection

=

29.972

mm

Actual Deflection

=

29.630

mm

 

< 

29.972

Slab Is Safe In Deflection