Analysis of Ribbed Slab

C-25 S-300Km Ks

19.00 3.9520.00 3.9621.00 3.9622.00 3.9723.00 3.9824.00 3.9825.00 3.9926.00 4.0027.00 4.0228.00 4.0329.00 4.0430.00 4.0531.00 4.0632.00 4.0733.00 4.0834.00 4.0935.00 4.1036.00 4.1137.00 4.1238.00 4.1539.00 4.1740.00 4.1841.00 4.2042.00 4.2143.00 4.2444.00 4.2645.00 4.2946.00 4.3147.00 4.3448.00 4.3649.00 4.3950.00 4.4151.00 4.4652.00 4.4953.00 4.5154.00 4.5655.00 4.6256.00 4.6557.00 4.6758.00 4.73

Design of slab mat fondatiooon

P1= 1308.60P2= 1368.00Mx= -My= - 3.5P3= 729.00P4= 849.60Mx= -My= -S-1= 1432.49 4S-2= 982.13S-3= 1575.45

N.B .For dimensions please refer the drawings

a)

8245.269 KN

17597.73

x= 2.13

17265.8655

y= 2.09

Eccentricity about the center of the slab

0.13 m

-0.09 m

b) Calculation of contact pressure

126.00

171.50

775.331107.19

277+-4.82*y+-4.82*x 6.15

247.71 6.46

273.54

226.18

252.00

Calculation of SP, e xand e y

SP

M1,2

MA,B

ex=

ey=

s=SP(1/A+-ex*y/Ix+-ey*x/Iy)

Ix= m4

Iy= m4

Mx=My=

s = Mx/Ix=

sA1= My/Iy=

sA2=

sB1=

sB2=

P1 P2

P3 P4

B

A

1 2

c) Calculation of Bending Moment and Determination of the Required Depth to Satisfy the shear stress

Divide them in to two equivalent beams

A1-B1 s= 236.94

A2-B2 s= 262.77

290.26 In the short direction

420.43 In the long direction

M= 295.61 Cantilever

Maximum shear would be the punching shear under the 1306KN

4x(0.4+d)dx641.67=1306

4x(0.4+d)d= 2.04

solving the quadratic equationd= 0.540 mD= 0.570 m

Reinforcement determination

I- short direction

Km= 31.55Ks= 4.06

f 20

2182.31 140 mm

II- Long direction

Km= 37.97Ks= 4.12

f 20

3207.72 98 mm

III- Cantilever

Km= 31.84Ks= 4.06

f 20

2222.58 140 mm

MAB=

M12=

4d2+1.6d-2.04=0

AS=

AS=

AS=

Shop and office Wzr Sewunet

Structural analysis and design

Design of Ribbed slabs / With Hollow concrete slabs/

Design Date

Concrete class- C-25

20 MPa

11.33 MPa

Steel grade S-300

300 Mpa

260.87 Mpa

Use Class I Workmanship

HCB size 40x24x20 cm

g= 14Concrete

g= 24Floor finish

g= 23 (Cement screed

g= 23 (Terrazzo tiles)

g= 16 ( PVC tiles)

g= 27 (Marle )

Design procedure

The ribs are placed at a clear spacing of 400mm.

The Depth of the topping is 60mm and the concrete strength

shall be of the same class as that of the ribs.

Loading

The function of the building is for office and shop(Mixed use).Therefore the live loading depends on the specific use of the floors.

Shop 5.00

Department sores 5.00

Offices 3.00

Restaurants and dining rooms 3.00

fck=

fcd=

fy=

fyd=

KN/m3

KN/m3

KN/m3

KN/m3

KN/m3

KN/m3

KN/m2

KN/m2

KN/m2

KN/m2



References:EBCS 1, 2, 3 ,& 8

Slab Analysis Solid slabs are preferable in areas where soil waste pipes pass.

Slabs for first floor and second floor

.=Panel Type Case No220.00 11.33 1

300.00 260.87

0 S-1 1

Ratio calc. 1

30.00 40.00 1.14 38.57 1 -Continuous 30.00

Lx/4 0.88 0 -Discontinous

Panel Name S-1 D [mm] Panel Name

Depth Lx [m] Ly [m] d [mm] 60.00 Depth

3.50 4.00 38.57 36.30 200.00

D-Load Floor finish 5cm Screed Weight Ceiling PlasterOther.D.Load D-Load

0.06 1.15 5.00 0.46 0.00

Wall Load L(in) L(out) Wall HeightWall unit weight q Wall Load

1.70 1.70 2.70 3.30 2.50

Total dead load 9.17 Cover [mm] Total dead load

Live Load 5.00 15.00 Live Load

Design load 0.88 19.93 Design load

r values r values

0.00 1.33 1.33 1.33 1.00

Alpha values b Alpha values

0.045 0.037 0.034 0.028 0.32

Moment Mxs Mys Mxf Myf Moment

10.98 9.03 8.30 6.83

k-value 340 280 260 220 k-value

r 0.13 0.11 0.10 0.08 r

Amin[sq.mm] 300 300 300 300 Amin

Ascal [sq.mm] 238 195 179 147 Ascal

Asfinal [sq.mm] 300 300 300 300 Asfinal

f # of bars # of bars # of bars # of bars f10.00 5 5 5 5 10.00

S.max [mm] 400 400 400 400 S.max [mm]

S.calc[mm] 260.00 260.00 260.00 260.00 S.calc [mm]

S.final [mm] 260.00 260.00 260.00 260.00 S.final [mm]

Load Transfer on Beams Ly/Lx= 1.14

Shear coeffcien Shear coeffcie

#DIV/0! 0.00 0.36 0.24

Load on Beams #VALUE! Load on Beam

Total design lo #DIV/0! N.A. 25.11 16.74 Total design l

Live Load #DIV/0! N.A. 6.30 4.20 Live Load

Dead Load #DIV/0! N.A. 11.56 7.71 Dead Load

Note:- N.A.-Means Not Applicable

Fck Fcd Fck

Fyk Fyd Fyk

ba for 2:1 ba for 1:1 ba calc ba for 2:1

ba calc

r1 r2 r3 r4 nd

axs a ys a xf a yf

bvcx bvdx bvcy bvdy

Rdx Rcy Rdy

Fck for C25 is 20Mpa



Analysis and design of staircase

Depth determinationd= 133.52 mmD= 164.52 mm

Use D= 200.00 mmd= 169.00 mm

q= 29.740.52 rad

Dead load Inclined part Concrete 4.8

Screeed 0.69Marble 0.54

tread + riser 0.54

Total 6.57

Live load 5

7.57

5.00

17.84

Landing partConcrete 4.8Screeed 0.69

Marble 0.54Total 6.03 Kn/m

Live load 3Pd= 12.64

17.84

12.64 12.64

a b

1.25 2.52 1.6

Reaction determinationTaking moment about b)

Ra= 23.91Rb= 57.06

Mmax= 22.01 Kn-m SpanMmax= -15.92 Kn-m Support

Km= 27.76Ks= 4.02

Ascal= 522.81Reinf 12 c/c 150 mm

o

Kn/m2

Kn/m2

Pdead=

Plive=

Pd=

Kn/m2



x M(x) Mmax

0 - 0.20 (4.53) 0.40 (8.55) 0.60 (12.07) 0.80 (15.08) 1.00 (17.59) 1.20 (19.59) 1.40 (20.06) 1.60 (19.49) 1.80 (18.21) 2.00 (16.21) 2.20 (13.50) (13.50) 2.40 (10.08) 2.60 (5.94) 2.80 (1.09) 3.00 4.47 3.20 10.75 3.40 17.74 3.60 25.44 3.77 32.55 3.80 30.84 4.00 19.76 4.20 9.18 4.40 (0.89) 4.60 (10.46) 4.80 (19.52) 5.00 (28.07) 5.20 (36.12) 5.37 (42.57)

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6

-10

-5

0

5

10

15

20

25

30

35

Column D



Slabs for third floor and fourth floor

.=Panel Type Case No220.00 11.33 1

300.00 260.87

2.55 1.51 0 S-1 1

Ratio calc. 1

40.00 1.14 38.57 1

Lx/4 0.88 0 -Discontinous

S-1 D [mm]

Lx [m] Ly [m] d[mm] 60.00

3.50 4.00 38.57 36.30 270.00

Floor finish5cm Screed Weight Ceiling PlasterOther.D.Load

0.06 1.15 6.75 0.35 0.00

L(in) L(out) h Wall unit weight q

1.70 1.70 2.70 3.30 2.50

Total dead load 10.81 Cover [mm]

3.00 15.00

18.85

0.00 1.33 1.33 1.33 1.00

b0.045 0.037 0.034 0.028 0.32

Mxs Mys Mxf Myf

10.39 8.54 7.85 6.47

170 140 130 110

0.06 0.05 0.05 0.04

417 417 417 417

161 132 121 100

417 417 417 417

# of bars # of bars # of bars # of bars

7 7 7 7

540 540 540 540

180.00 180.00 180.00 180.00

180.00 180.00 180.00 180.00

Load Transfer on Beams Ly/Lx= 1.14

0.42 0.00 0.36 0.24

Rcx Rdx Rcy Rdy

27.97 N.A. 23.75 15.84

4.45 N.A. 3.78 2.52

16.04 N.A. 13.62 9.08

Fcd

Fyd

ba for 1:1 ba calc

ba calc

r1 r2 r3 r4 nd

axs a ys a xf a yf

bvcx bvdx bvcy bvdy



0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6

-10

-5

0

5

10

15

20

25

30

35

Column D



1) Design of Ribbed slabs / With Hollow concrete slabs/

Design Date

Concrete class- C-25

20 MPa

11.33 MPa

Steel grade S-300

300 Mpa

260.87 Mpa

Use Class I Workmanship

HCB size 40x24x20cm

14Concrete

24Floor finish

23 (Cement screed

23 (Terrazzo tiles)

16 ( PVC tiles)

27 (Marle )

2) Design procedure

The ribs are placed at a clear spacing of 400mm.

The Depth of the topping is 60mm and the concrete strength

shall be of the same class as that of the ribs.

fck=

fcd=

fy=

fyd=

g= KN/m3

g= KN/m3

g= KN/m3

g= KN/m3

g= KN/m3

g= KN/m3



2.1 Loading

The function of the building is for hospital.Therefore the live loading depends on the specific use of the floors.

Offices 3.00

Wards 3.00

Rib slab

Topping 60mm use f 8 c/c200mm

Each rib carry half of the load b/n the ribsLoading

Dead load HCB 1.34 KN/mConc. Topping 0.58 KN/m

Plastering 0.29 KN/mPVC tiles 0.02 KN/m

Light wt. conc 0.92 KN/mTotal 3.14 KN/mLive Load 1.50 KN/m

Load carried by end ribDead load 1.57 KN/m

Live Load 0.75 KN/m

Load carried by intermidiate ribDead load 3.14 KN/m

Live Load 1.50 KN/m

Analyze and design the rib beams as per the AR requirment

KN/m2

KN/m2

Analysis of Ribbed Slab

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