DN400

(1)

Calculations for Isolation Valve Chamber for DN400 @ CH 0+003

1 Design Parameters

for

IVC-DN400

1.1 Soil Condition

From Geotechnical report

Reference Bore Hole

near BH-6

Net Allowable Bearing Pressure

=

160 @ Depth =

2 m

Soil Parameters used in Design

For layer designation -

Angle of Internal Friction for Soil Pressure Calculations

30 °

0.524 radians

Ka =

0.33 Kp =

3.00 Soil Pressure at Rest Coeff.

0.50 Angle of Internal Friction for Friction Calculations

30 °

=

0.524 radians

Friction Factor Concrete/Soil

0.36 Friction Factor Soil/Soil

=

0.58 Net Allowable Bearing Pressure

=

160

1.2 Unit Weights

Soil Bulk Density

17.0 Submerged Soil Density

7.0 Density of Water

10.0 Concrete Density

24.0 Submerged Concrete Density

14.0

1.3 Materials

(1)

Concrete

Specified Characteristic Strengt

30 Elastic Modulus

28,000

kN/m

2



=

Active Coefficient K

_a

= (1-Sinf/1+Sinf)

Passive Coefficient K

_p

= (1+Sinf/1-Sinf)

K

₀

=



=



= Tan (2/3.



)



= Tan



kN/m

2



=

kN/m

3



' =

kN/m

3



w

=

kN/m

3



c

=

kN/m

3



c'

=

kN/m

3

f

_c

=

_N/mm

2

E

_s

=

_N/mm

2

(2)

1.4 Factors of Safety

Stability of Structure

Required Factor of Safety Against Sliding =

1.4 Required Factor of Safety Against Overturning =

1.5 Required Factor of Safety Against Flotation =

1.2 Required Factor of Safety Against Rotation =

1.5 Factor of Safety Against Allowable Bearing Capacity

1.0

1.5 Load Combination

Ultimate Limit State

1.4[D.L.]+1.4[S.P]+1.6[I.L]+1.4[T.F]

i.e.

Partial Load Factor for Dead Load = 1.4

Partial Load Factor for Soil Pressure = 1.4

Partial Load Factor for Imposed Load = 1.6

Partial Load Factor for Pipeline Thrust = 1.6

Serviceability Limit State

1.0[D.L.]+1.0[S.P]+1.0[I.L]+1.0[T.F]

i.e.

Partial Load Factor for Dead Load = 1.0

Partial Load Factor for Soil Pressure = 1.0

Partial Load Factor for Imposed Load = 1.0

Partial Load Factor for Pipeline Thrust = 1.0

2. Pipe Details

Maximum Pressure for design

P =

16.0 bar

Pressure in SI units

1,600

Int. Dia

0.400 m

Ext Dia

0.429 m

Inner Area

0.126 Externa Area

0.145 In Line Force TF

201 kN

Weight of Pipe

=

0.89 kN/m

No. of valves closed

1

3. Chamber Dimensions and Levels

Base Length

D =

4.12 m

Base Width

B =

4.81 m

Chamber width -inner dimension

2.41 m

Chamber length -inner dimension

2.59 m

Side wall thickness

0.30 m

Pipe Invert Level

IL =

14.17 m

Ground Level

GL =

18.30 m

Finished Ground Level

FGL =

18.30 m

Water Table Level

WL =

0.00 m

DRY

Type of Construction

TC

III

Top of Base Slab Level

TBL =

13.87 m

Top of Chamber Wall Level

TWL =

18.60 m

U

_u

=

U

_s

=

kN/m

2

m

2

m

2

b

₁

=

d

₁

=

t

_SW

=

(3)

B

1.20

2.41

1.20

0.78 Back Wall

0.3

1.01

0.80

0.3

0.30

2.41 m

0.5 A

A

1.94 2.59 m

1.217

2.59

4.12

0.55

0.35 Front Wall

0.75 Cover Slab line

`

Rotating Point

B

PLAN

0.3

4.43 0.5145

0.60

4.81 SECTION A-A

WTL

4.43 5.63 m

0.5145

Flow

0.30

0.60

0.50

3.1

0.50 Overturning

4.1 Point

(4)

(5)

4. Stability Check

4.1 Bearing Capacity Check

Factor of Safety Required

1.0 a) Calculation of Pipe Thrust

Pressure in bar

16.0 bar

Pressure in SI units

1,600

Int. Dia

0.400 m

Ext Dia

0.429 m

Inner Area

0.126 Externa Area

0.145 In Line Force TF

201 kN

No. of valves closed

1 b) Volumes and Weights

Concrete Density

24.0 Submerged Concrete Density

14.0 Concrete

Volume

Weight

kN

Shear Key (front)

1.44

34.60 Shear Key (back)

1.44

34.60 Foundation Slab

11.87

284.92 Front Wall (minus pipe hole)

3.93

94.38 Back Wall (minus pipe hole)

3.37

80.90 Side Walls1

2.76

66.14 Side Walls2

2.76

66.14 Precast Cover Slab

1.25

29.93

28.82

691.62 Soil, Water & Pipe

Soil Bulk Density

17.0 Submerged Soil

7.0 Density of Water

10.0 Weight of Pipe

=

0.89 kN/m

Volume

Weight

kN

Soil from FGL to TBL - front (minus pipe)

15.86

269.61 Soil from FGL to TBL - back (minus pipe)

16.39

278.60 Soil from FGL to TBL - side1

13.78

234.24 Soil from FGL to TBL - side2

13.78

234.24 Pipe including Water

8.8 length of pipe is taken

for the entire chamber base

1026

c) Bouyant Force

No bouyant force since no water level is encountered.

kN/m

2

m

2

m

2



c

=

kN/m

3



c'

=

kN/m

3

m

3



=

kN/m

3



' =

kN/m

3



w

=

kN/m

3

m

3

(6)

e) Soil pressure calculations for the bearing capacity check :

(Water table above TBL)

Active Soil Pressure (for Bearing Capacity and Overturning check)

Angle of internal friction

30 °

Active pressure coefficient

Ka =

0.33 Soil Bulk Density

17.0 Submerged Soil Density

7.0 Width of chamber wall

2.41 m

Width of foundation slab

4.81 m

Total Active soil pressure

Force

a1

(at wall)

=

133.78 kN

a2

(at foundation slab)

=

164.38 kN

Active Soil Pressure

0.00 4.43 m

25.10 1.20 m

31.90 Passive Soil Pressure (for Bearing Capacity and Overturning check)

Angle of internal friction

30 °

Passive pressure coefficient

Kp =

3.00 Soil Bulk Density

17.0 Submerged Soil Density

7.0 Width of chamber wall

2.41 m

Width of foundation slab

4.81 m

Total Passive soil pressure assumed at foundation base slab level only for conservative design.

Passive pressure at TBL

=

225.93 Passive pressure bottom shear key =

=

287.13 Total Passive force from TBL to bottom shear key

=

-1479.46 kN

Moments about Centre of Base

Force

Lever

Moment

(service) (ultimate)

Arm

(service)

(ultimate)

kN

m

kN.m

Clockwise Positive

- Pipe Thrust

201.06

1.71

344.72

551.55 - Active soil pressure

(Above TBL)

a1 =

133.78

2.08

277.82

388.95 - Active soil pressure

(Below TBL)

a2 =

164.38

0.60

98.63

138.08 -

Passive soil pressure below TBL

p1 = -1479.46

0.60 -887.68 -1242.75



=



=

kN/m

3



' =

kN/m

3

b

₁

=

b

₂

=

kN/m

2

p

₁

=

ka.d1.



=

_kN/m

2

p

₂

= ka.(d1+d2).



=

kN/m

2



=



=

kN/m

3



' =

kN/m

3

b

₁

=

b

₂

=

kp.d1.



=

_kN/m

2

kp.(d1+d2).



=

kN/m

2

P

₂

d1 =

FGL TBL

d2 =

p

₁

p

₂

a1

a2

P

₁

d1 =

FGL TBL

d2 =

p

₁

p

₂

a1

a2

P

₂

P

₂

(7)

- Shear Key (front)

=

34.60

48.44 -1.81

-62.58

-87.61

Shear Key (back)

=

34.60

48.44

1.81

62.58

87.61 Foundation Slab

=

284.92

398.89

0.00

0.00 Front Wall

=

94.38

132.13 -1.15

-108.16

-151.42

Back Wall

=

80.90

113.26

1.12

90.69

126.96 Side Walls1

=

66.14

92.59

0.00

0.00 Side Walls2

=

66.14

92.59

0.00

0.00 Precast Cover Slab

=

29.93

41.91

0.00

0.00 - Soil from FGL to TBL - front

=

269.61

377.46 -1.68

-453.89

-635.45

Soil from FGL to TBL - back

=

278.60

390.04

1.67

465.54

651.75 Soil from FGL to TBL - side1

=

234.24

327.94

0.00

0.00 Soil from FGL to TBL - side2

=

234.24

327.94

0.00

0.00 - Pipe including Water

=

9

12.37

0.00

0

0.00 - Boyant force

=

0.00

0

0.00 Total Moment

-172

Total Vertical Load

1,717

2,404

Moment M

=

-172 kN.m

Vertical load N

=

1,717 kN

Base Length

D =

4.12 m

Base Width

B =

4.81 m

Base Area

=

19.79 Average load on base = N/BD

=

87 Effective eccentricity e = M/N =

-0.10 m

Middle third of the base = D/6

=

0.69 m

-13

99.5

74 a =

4.12 m

Allowable bearing pressure

=

160 Factor of safety against soil bearing pressure

=

2.16 OK

4.2 Resistance to Overturning

Factor of Safety Required

1.5 Force

Dist from

Moment

m

2

kN/m

2

Variation due to moment = 6M/BD

2

₌

_kN/m

2

P

₁

=

_kN/m

2

P

₂

=

_kN/m

2

kN/m

2

(8)

721 Total Overturning Moments M

_o

(9)

Stabilising Moments:

Shear Key (front)

=

34.60

3.87

134 Shear Key (back)

=

34.60

0.25

9 Foundation Slab

=

284.92

2.06

587 Front Wall

=

94.38

3.19

301 Back Wall

=

80.90

0.93

75 Side Walls1

=

66.14

2.05

135 Side Walls2

=

66.14

2.05

135 Precast Cover Slab (ignored)

=

0.00

2.05

0 Soil from FGL to TBL - front

=

269.61

3.74 1,009

Soil from FGL to TBL - back

=

278.60

0.39

108 Soil from FGL to TBL - side1

=

234.24

2.07

485 Soil from FGL to TBL - side2

=

234.24

2.07

485 Pipe including Water

9

2.06

18

Passive soil pressure above TBL

0

0.00

0

Passive soil pressure below TBL

1,479

0.60

888 4,369

Factor of Safety Against Overturning =

=

6.06 OK

4.3 Resistance to Sliding

Factor of Safety Required

1.4 Horizontal Forces:

Pipe Thrust

=

201 kN

Active soil pressure

(Above TBL)

a1 =

133.78 kN

Active soil pressure

(Below TBL)

a2 =

164.38 kN

Total horizontal sliding force

H =

499.23 kN

Vertical Forces:

Concrete weight

=

691.62 kN

Soil weight

= 1,016.70 kN

Pipe with water

=

8.838 kN

Bouyant force (uplift)

=

0.00 kN

Total vertical force

V = 1,717.15 kN

Frictional resistance soil

0.58 Frictional resistance from vertical force =

=

991.40 kN

Passive soil pressure (Below TBL)

= 1,479.46

Total resisting force

Fr= 2,470.86

Factor of safety against Sliding

=

Fr / H

=

4.95 OK

Total Stabilising Moments M

_s

M

_s

/M

_o

to soil,



=



. V

(10)

4.5 Resistance to Rotation

Factor of Safety Required

1.5 Forces acting on the chamber

Pa1 = a1+a2+a3

Pa2 = a4+a5

Pp1 = 0 (neglected)

Pp2 = pass pressure

below TBL

Rotating Point

In addition to the forces shown

there is friction on the base

Rotation Moment

Pipe Thrust

=

201

2.51

503.86 Active pressure at front wall:

Active soil pressure

(Above TBL)

a1 =

133.78

2.40

321.48 Active soil pressure

(Below TBL)

a2 =

164.38

2.40

395.02 Activer pressure at side wall:

Active soil pressure

(Above TBL)

a1 =

133.78

2.06

275.39 Active soil pressure

(Below TBL)

a2 =

164.38

2.06

338.39 Rotation Moment sum

=

1,834

kN-m

Resisiting Moment

Total vertical loads (including bouyancy)

V =

1,717.15

Frictional resistance

soil

to soil,

0.58 Frictional resistance at base

991.40 kN

Moment arm

=

3.16 m

Frictional resistance against Rotation

=

3,136.93 kN.m

1,479

2.40 3,555.14

1,479

2.06 3,045.47

Resistance Moment sum

9,737.54

Factor of Safety Against Rotation

=

5.31 OK

5. Summary of Results

Given below is the summary of the Stability Checks for the Chamber.

The required values of safety are compared with the ones obtained from the calculation.

Required Calculated

Pmax

99 Pmin

74 Bearing

1

2.16 Overturning

1.5

6.06 Sliding

1.4

4.95 Rotation

1.5

5.31 

=



. V =

Passive soil pressure below TBL (backwall) = Passive soil pressure below TBL (sidewall) =

Pa1

T

Pp1

Pa2

Pa1

Pa2

Pp2

Pp1

Pa1

T

Pp1

Pa2

Pa1

Pa2

Pp2

Pp1

(11)

6. Design Ultimate Loads on foundation and shear key:

Toe

Heel

5.03 m 5.63 m 4.12 3.35 0.76 0.00

Ultimate Moment M

=

-172 kN.m

Ultimate Vertical load N

=

2,404 kN

Base Length

D =

4.12 m

Base Width

B =

4.81 m

Base Area

=

19.79 Average load on base = N/BD

=

121.50 Effective eccentricity e = M/N =

-0.07 m

Middle third of the base = D/6

=

0.69 m

-12.69

Design Ultimate Soil Bearing Pressure:

134 <-- at Heel

109 <-- at Toe

129.49 <-- at Face of front wall

113.51 <-- at Face of backwall

Design moment at Heel

=

38.55 kN-m/m strip

Desing moment at Toe

=

32.09 kN-m/m strip

Design shear at Heel

=

100.53 kN/m strip

Design shear at Toe

=

84.76 kN/m strip

Design Ultimate Passive moment on shear key =

74.93 kN-m/m strip

Design Ultimate Passive shear on shear key =

228.34 kN/m strip

359.14 kN/m

401.98 kN/m

Note: Values of stresses calculated here can be compared with Staad results finite element analysis.

Maximum values as per the two results shall be used in the design of walls, base slab & shear key.

m

2

kN/m

2

Variation due to moment = 6M/BD

2

₌

_kN/m

2

P

₁

=

_kN/m

2

P

₂

=

_kN/m

2

P

₃

=

_kN/m

2

P

₄

=

_kN/m

2

P

₅

=

P

₆

=

Chamber

wall edges

Chamber

wall edges

(12)

7. Punching Shear Check of Front Wall

The thrust force on wall acts like punching force from column on the flat slab. Hence the

wall thickness should be checked for the value of shear stress at flange edge.

Punching Perimeter

DN

400 Flange

Chamber Wall Thickness

h =

0.35 m

Pipe External diameter

=

429 mm

Pipe Pressure

=

16.0 bar

Flange Diameter

Df =

565 mm

Pipe Thrust Force

=

201 kN

Thrust Force Distribution Ratio

=

1.00 Pipe Thrust force on wall

=

201 kN

Factored Thrust Force on Wall

=

322 kN

Characteristic Strength of Concrete (fcu)

30

4.38 Specified Yield Strength

460 Concrete Cover

cc =

75 mm

Main Reinforcement provided

f =

12 mm

Spacing =

150 mm

Total Effective Depth

d =

269.0 mm

Effective depth from the flange face

=

94.0 mm

1.93

Safe < 5N/mm2 , 0.8 Sqrt(fc)

Shear at First Perimeter

Punching shear stress at first perimeter should be less than the shear strength of reinforced

concrete. Otherwise shear links to be provided to resist the punching shear stress.

In this calculation punching perimeter is taken at 1.5 times the effective depth calculated

from the face of flange.

Distance to first punching perimeter from the flange edge

=

141 mm

Distance to bot slab from flange edge

232 mm

Punching perimeter = 4.[(flange diameter+2x1.5.df)]

u =

3388 mm

Diameter of perimeter =

1078 mm

Punching Shear Stress

V =

1.01 Shear stress at flange edge should not exceed 5 N/mm

2

_{and 0.8(f'cu)}

1/2.

N/mm

2

0.8 (fcu)

1/2

₌

_N/mm

2

f

_y

=

_N/mm

2

d

_f

= h/2-Cc-f/2

Shear at the edge

of pipe flange

V

f

=

N/mm

2

with shear area =



Dfd

_f

a

_v

=

(13)

Area of Main Steel

As =

754 r =

0.280 Concrete Shear Stress

Vc =

0.44 Table 3.8 BS 8110

V > Vc , Shear links reqd.

V-Vc =

0.57 Area of punching links req.

Asv =

416 Link diameter

=

12 mm

Number of legs required

=

3.68 Nos.

Spacing of legs required

=

1,842 mm

Maximum Spacing

0.75.df

=

141 mm

Spacing Provided

=

300 mm

Provide T12 links at 300 spacing in a matrix within the chamber wall, from end to end in both directions.

Shear on Second Perimeter

For the second punching perimeter consider the total effective depth of the section.

0.75d=

202 mm

Punching perimeter = 4.[(flange diameter+2x1.5.df+2x(0.75) d)]

u =

5002 mm

Diameter of perimeter =

1592 mm

Punching Shear Stress

V =

0.24 Area of Main Steel

As =

754 r =

0.802 Concrete Shear Stress

Vc =

0.62 Table 3.8 BS 8110

V < Vc , Shear links not reqd.

Bearing Stress at Flange Face

Pipe External Diameter

=

0.429 m

Flange Diameter

=

0.565 m

Surface Area of Flange

=

0.106 Thrust Acting on One Wall

=

322 kN

Bearing Stress

=

3.03 Allowable Bearing Stress

=

12 O.K.

mm

2

N/mm

2

N/mm

2

(V-Vc).d.u/(0.95.f

_y

)

mm

2

_/m

N/mm

2

mm

2

N/mm

2

m

2

N/mm

2

0.4.f

_cu

N/mm

2

(14)

(15)

8. Reinforcement Calculation for Chamber Walls & Base Slab

The Analysis of the Chamber is perfromed using STAAD software. Staad results for the walls shall

be used in the design. Results for base slab foundation and shear key stresses shall be compared with

the results from Section-6 (page 10) of this appendix and maximum values shall be used.

8.1 Loads and Load Combinations

The load combination of Pipe thrust force with lateral soil pressure on all sides of the chamber walls

and shear keys has been used in the Staad model. A surcharge of 10kN/sq.m has been assumed as

additional load for the chamber design of the walls. Passive pressure and water pressure are also

added in the design of the chamber walls.

Load 1 - Concrete Selfweight plus Pipe weight

Concrete selfweight calculated automatic by Staad

Cover slab weight = nodal concentrated load at top of wall =

0.58 kN over 52 points

at top of wall

Pipe selfweight at Front & back wall =

0.89 x Pipe length over base slab projection / 2

=

1.83 kN or at 3 points per wall

=

0.61 kN over 3 points per wall at pipe opening.

Load 2 - Thrust Force from Pipe & Weight of Water

Wall is modelled as a combination of square and rectangular plate elements.

The Front wall of the Chamber takes 100% of the Thrust. This Thrust is distributed equally over

6 points in the STAAD model.

Thrust from pipeline

201 kN

Thrust distributed over six points

34 kN

Weight of water at Pipe

=

1.26 x Pipe length over base slab projection / 2

=

2.59 kN or at 3 points per wall

=

0.86 kN over 3 points per wall at pipe opening.

Load 3 - Active and Passive Soil Pressure

4.43 1.20

P

Q

d1 =

FGL TBL

d2

=

p

₁

p

₂

p

₀

d1 =

FGL TBL

d2

=

p

₁

p

₂

p

₀

(16)

Active Press at Front Wall for Staad Input ->

Soil

Water (Pw)

Sur (Q)

Total (kN/m2)

0

3.33

25.10

0

3.33

28.44

31.90

0

3.33

35.24

Passive Press at backwall for Staad Input ->

Soil

Water (Pw)

Sur (Q)

Total

0

30.00

225.93

0

30.00

255.93

287.13

0

30.00

317.13 Load 4- Side Walls pressure

At Rest Press for Sidewalls Staad Input ->

Soil

Water (Pw)

Sur (Q)

Total (kN/m2)

0

5.00

37.66

0

5.00

42.66 Load 5 - Soil Weight at TBL

75.31 <-- at Top of foundation slab (TBL)

Load combination 6 - Service load combinations

Load combination 7 - Ultimate load combinations

Note:

Load 3 & 4 are modelled into STAAD in increments corresponding to chamber height, on side walls

back wall and front thrust wall.

8.2 Analysis Results

Factored Results for Design ( STAAD Result as per Loadcomb-7) - per meter width

Front Wall

43.4

44.3

715.0

340.0

250.3

119.0 Back Wall

36.6

33.4

576.0

523.0

172.8

156.9 Side wall

10.9

27.9

154.0

272.0

46.2

81.6 Base slab

325.0

72.4

482.0

485.0

289.2

291.0 Shear key

190.0

47.5

962.0

177.0

481.0

88.5 P

₀

P

₁

P

₂

P

₀

P

₁

P

₂

P

₀

P

₁

W

_soil

=

_

* (d1+d2) =

kN/m

2

MX

kNm/m

MY

kN/m2

SQX

kN/m2

SQY

SQX

kN/m

SQY

kN/m

(17)

8.3 Reinforcement Design for Front Thrust Wall

Design for Moment at Thrust Wall

Design Moment

M

44

kN.m/m

(At location adjacent opening)

Concrete Strength 30 Steel Strength 460 Width of Section

b

1000

mm

Depth of Section

h

350

mm

Bar Diameter f 12

mm

Clear Cover

Cc.

75

mm

Effective Depth

d

269

mm

Ultimate Moment Resistance

Mu

339

kN.m

K

0.020

Lever-arm factor

La

0.977

La=Z/d

Lever-arm

Z

256

mm

Z= MIN(0.95d , La.)

Area of Steel Required

As

397

As=M/(0.95 fy Z)

Minimum Area of Steel As< Asmin

Asmin

455

Asmin= 0.0013.bh

No. of Bars Required 4.03 T 12

No. of Bars Provided 6.67 T 12

Area of Steel Provided

As

754

Design for Shear at Thrust Wall

Design Shear Force

V

250

kN/m

Concrete Strength

fcu

30

Steel Strength

fy

460 Width of Section

b

1000

mm

Depth of Section

h

350

mm

Bar Diameter f 12

mm

Clear Cover

Cc.

75

mm

f

_cu

_N/mm

2

f

_y

_N/mm

2

d=h-Cc.-(

f/2) Mu=0.156 fcu bd2 K=M/fcubd2

mm

2

mm

2

mm

2_/m

N/mm

2

N/mm

2

(18)

V 0.25

Vc

0.44

Area of links

Asv

-Asv/Sv

-Spacing Required

Sv

Not reqd.

mm

Spacing Provided

Sv

-

mm

Crack Width Verification at Thrust Wall

Ref. BS 8007 Appendix B

Service Moment/m

Ms

28 kNm/m

Characteristic Strength of Concrete

fcu

30 Yield strength of Steel

fs

460 Modular ratio

a

15 Distance from the compression face to the point

at which the crack width is being calculated =a'

350 mm

Cover

75 mm

Main Bar diameter

12 mm

Spacing

150 mm

Distribution bar diameter

12 mm

Spacing

150 mm

b

1,000

mm

200 d

257 mm

h-x

284 mm

d-x

191 mm

As

754 0.0029

0.0440

depth to neutral x/d =

(-m)+SQRT(m(2+m))

0.2559

x

66 mm

z =d-x/3

235 mm

Reinforcement stress

156 0.00078

Strain at surface of concrete

0.00116

Strain due to stiffening effect of concrete between cracks

0.0009

Average strain

0.0002

Distance from the point considered to the

surface of the nearest longitudinal bar acr

104 mm

Calculated surface crack width

0.059 mm

Maximum crack width allowed

0.200 mm

OK

N/mm

2

N/mm

2

mm

2

N/mm

2

N/mm

2

E

_s

_kN/mm

2

mm

2

r =As/bd

m= ar

fs =M

_s

/(A

_s

x z)

_N/mm

2

e

_{s =}

f

_s

/E

_s

e

_{1 =}

e

_s

(h-x)/(d-x)

e

_{2 =}

b (h-x) (a'-x)/ 3EsAs(d-x))

e

_m

=e

₁

-e

₂

(19)

8.4 Reinforcement Design for Back Wall

Design for Moment at Back Wall

Design Moment

M

36.6

kN.m/m

b

1000

mm

Depth of Section

h

300

mm

Bar Diameter f 12

mm

Clear Cover

Cc.

75

mm

Effective Depth

d

219

mm

Mu

224

kN.m

K

0.025

Lever-arm factor

La

0.971

La=Z/d

Lever-arm

Z

208

mm

Z= MIN(0.95d , La.)

As

403

As=M/(0.95 fy Z)

Minimum Area of Steel As>Asmin

Asmin

390

Asmin= 0.0013.bh

As

754

Design for Shear at Back Wall

Design Shear Force

V

173

kN/m

(at d distance from face wall)

Concrete Strength

fcu

30

Steel Strength

fy

b

1000

mm

Depth of Section

h

300

mm

Bar Diameter f 12

mm

Clear Cover

Cc.

75

mm

f

_cu

_N/mm

2

f

_y

_N/mm

2

d=h-Cc.-(

mm

2

mm

2

mm

2_/m

N/mm

2

N/mm

2

(20)

V 0.17

Vc

0.47

Area of links

Asv

-Asv/Sv

-Spacing Required

Sv

Not reqd.

mm

Spacing Provided

Sv

mm

(Around bottom corners of backwall only)

Crack Width Verification at Back Wall

Ref. BS 8007 Appendix B

Service Moment/m

Ms

23 kNm/m

Characteristic Strength of Concrete

fcu

30 Yield strength of Steel

fs

460 Modular ratio

a

15 Distance from the compression face to the point

at which the crack width is being calculated =a'

300 mm

Cover

75 mm

Main Bar diameter

12 mm

Spacing

150 mm

Distribution bar diameter

12 mm

Spacing

150 mm

b

1,000

mm

200 d

207 mm

h-x

242 mm

d-x

149 mm

As

754 0.0036

0.0546

depth to neutral x/d =

(-m)+SQRT(m(2+m))

0.2804

x

58 mm

z =d-x/3

188 mm

Reinforcement stress

162 0.00081

Strain at surface of concrete

0.00131

Strain due to stiffening effect of concrete between cracks

0.0009

Average strain

0.0004

Distance from the point considered to the

surface of the nearest longitudinal bar acr

104 mm

Calculated surface crack width

0.112 mm

Maximum crack width allowed

0.200 mm

OK

N/mm

2

N/mm

2

mm

2

N/mm

2

N/mm

2

E

_s

_kN/mm

2

mm

2

r =As/bd

m= ar

fs =M

_s

/(A

_s

x z)

_N/mm

2

e

_{s =}

f

_s

/E

_s

e

_{1 =}

e

_s

(h-x)/(d-x)

e

_{2 =}

b (h-x) (a'-x)/ 3EsAs(d-x))

e

_m

=e

₁

-e

₂

(21)

(22)

8.5 Reinforcement Design for Side Wall

Design for Moment at Side Wall

Design Moment

M

28

kN.m/m

b

1000

mm

Depth of Section

h

300

mm

Bar Diameter f 12

mm

Clear Cover

Cc.

75

mm

Effective Depth

d

219

mm

Mu

224

kN.m

K

0.019

Lever-arm factor

La

0.978

La=Z/d

Lever-arm

Z

208

mm

Z= MIN(0.95d , La.)

As

307

As=M/(0.95 fy Z)

Asmin

390

Asmin= 0.0013.bh

As

754

Design for Shear at Side Wall

Design Shear Force

V

82

kN/m

Concrete Strength

fcu

30

Steel Strength

fy

460

Width of Section

b

1000

mm

Depth of Section

h

300

mm

Bar Diameter f 12

mm

Clear Cover

Cc.

75

mm

Details of Links No and

mm

Effective Depth

d

219

mm

Area of Main Steel

As

754

f

_cu

_N/mm

2

f

_y

_N/mm

2

d=h-Cc.-(

mm

2

mm

2

mm

2_/m

N/mm

2

N/mm

2 f of Link

d=h-Cc.-f

_L

-(

f/2)

mm

2

(23)

V 0.08

Vc

0.47

Area of links

Asv

-Asv/Sv

-Spacing Required

Sv

Not reqd.

mm

Spacing Provided

Sv

mm

Crack Width Verification at Side Wall

Ref. BS 8007 Appendix B

Service Moment/m

Ms

17 kNm/m

Characteristic Strength of Concrete

fcu

30 Yield strength of Steel

fs

460 Modular ratio

a

15 Distance from the compression face to the point

at which the crack width is being calculated =a'

300 mm

Cover

75 mm

Main Bar diameter

12 mm

Spacing

150 mm

Distribution bar diameter

12 mm

Spacing

150 mm

b

1,000

mm

200 d

207 mm

h-x

242 mm

d-x

149 mm

As

754 0.0036

0.0546

depth to neutral x/d =

(-m)+SQRT(m(2+m))

0.2804

x

58 mm

z =d-x/3

188 mm

Reinforcement stress

123 0.00062

Strain at surface of concrete

0.00100

Strain due to stiffening effect of concrete between cracks

0.0009

Average strain

0.0001

Distance from the point considered to the

surface of the nearest longitudinal bar acr

104 mm

Calculated surface crack width

0.033 mm

N/mm

2

N/mm

2

mm

2

N/mm

2

N/mm

2

E

_s

_kN/mm

2

mm

2

r =As/bd

m= ar

fs =M

_s

/(A

_s

x z)

_N/mm

2

e

_{s =}

f

_s

/E

_s

e

_{1 =}

e

_s

(h-x)/(d-x)

e

_{2 =}

b (h-x) (a'-x)/ 3EsAs(d-x))

e

_m

=e

₁

-e

₂

(3a

e

)/[1+2(a

-c

)/(h-x)]

(24)

(25)

8.6 Reinforcement Design for Base Slab

Design for Moment at Base Slab Toe

Design Moment

M

325

kN.m/m

b

1000

mm

Depth of Section

h

600

mm

Bar Diameter f 25

mm

Clear Cover

Cc.

75

mm

Effective Depth

d

513

mm

Mu

1229

kN.m

K

0.041

Lever-arm factor

La

0.952

La=Z/d

Lever-arm

Z

487

mm

Z= MIN(0.95d , La.)

As

1528

As=M/(0.95 fy Z)

Asmin

780

Asmin= 0.0013.bh

As

3274

Design for Shear at Base Slab

Design Shear Force

V

291

kN/m

Concrete Strength

fcu

30

Steel Strength

fy

b

1000

mm

Depth of Section

h

600

mm

Bar Diameter f 25

mm

Clear Cover

Cc.

75

mm

f

_cu

_N/mm

2

f

_y

_N/mm

2

d=h-Cc.-(

mm

2

mm

2

mm

2_/m

N/mm

2

N/mm

2

(26)

(27)

V 0.29

Vc

0.58

Area of links

Asv

-Asv/Sv

-Spacing Required

Sv

Not reqd.

mm

Spacing Provided

Sv

mm

Crack Width Verification at Base Slab

Ref. BS 8007 Appendix B

Service Moment/m

Ms

203 kNm/m

Characteristic Strength of Concrete

fcu

30 Yield strength of Steel

fs

460 Modular ratio

a

15 Distance from the compression face to the point

at which the crack width is being calculated =a'

600 mm

Cover

75 mm

Main Bar diameter

25 mm

Spacing

150 mm

Distribution bar diameter

25 mm

Spacing

150 mm

b

1,000

mm

200 d

488 mm

h-x

425 mm

d-x

312 mm

As

3,272

0.0067

0.1007

depth to neutral x/d =

(-m)+SQRT(m(2+m))

0.3592

x

175 mm

z =d-x/3

429 mm

Reinforcement stress

145 0.00072

Strain at surface of concrete

0.00098

Strain due to stiffening effect of concrete between cracks

0.0003

Average strain

0.0007

Distance from the point considered to the

surface of the nearest longitudinal bar acr

103 mm

Calculated surface crack width

0.188 mm

N/mm

2

N/mm

2

mm

2

N/mm

2

N/mm

2

E

_s

_kN/mm

2

mm

2

r =As/bd

m= ar

fs =M

_s

/(A

_s

x z)

_N/mm

2

e

_{s =}

f

_s

/E

_s

e

_{1 =}

e

_s

(h-x)/(d-x)

e

_{2 =}

b (h-x) (a'-x)/ 3EsAs(d-x))

e

_m

=e

₁

-e

₂

(28)

8.7 Reinforcement Design for Shear Key

Design for Moment at Shear Key

Design Moment

M

190.00

kN.m/m

b

1000

mm

Depth of Section

h

500

mm

Bar Diameter f 20

mm

Clear Cover

Cc.

75

mm

Effective Depth

d

415

mm

Mu

806

kN.m

K

0.037

Lever-arm factor

La

0.957

La=Z/d

Lever-arm

Z

394

mm

Z= MIN(0.95d , La.)

As

1103

As=M/(0.95 fy Z)

Asmin

650

Asmin= 0.0013.bh

As

2095

Design for Shear at Shear Key

Design Shear Force

V

481.0

kN/m

Concrete Strength

fcu

30

Steel Strength

fy

460

Width of Section

b

1000

mm

Depth of Section

h

500

mm

Bar Diameter f 20

mm

Clear Cover

Cc.

75

mm

Details of Links No and

mm

Effective Depth

d

415

mm

Area of Main Steel

As

2095

f

_cu

_N/mm

2

f

_y

_N/mm

2

d=h-Cc.-(

mm

2

mm

2

mm

2_/m

N/mm

2

N/mm

2 f of Link

d=h-Cc.-f

_L

-(

f/2)

mm

2

(29)

V 0.48

Vc

0.53

Area of links

Asv

-Asv/Sv

-Spacing Required

Sv

Not reqd.

mm

Spacing Provided

Sv

-

mm

N/mm

2

N/mm

2

mm

2

(30)

9. Design of Precast Cover Slab

Design Parameters

Characteristic Strength of Concrete

30 Specified Yield Strength

460 Concrete Cover

Cc =

50 mm

Main Reinforcement provided

f =

10 mm

Thickness of slab

h =

200 mm

Normal Condition

Span of Slab

l =

2592

mm

Self Weight

=

4.8 kN/m

Live Load

=

5 Factored Design Load

=

14.72 kN/m

2.41 Maximum Bending Moment

Mu =

12.36 kNm

Factored Shear

Vu =

19.08 kN

2.59 During Transportation

Span of Slab

l =

2592

mm

Self Weight

=

4.8 kN/m

0.80 Live Load

=

5 Factored Design Load

=

14.72 kN/m

Maximum Bending Moment

Mu =

12.36 kNm

Weight of the precast unit

1.34 kN

From transporting sling, weight considered is

N (half of the weight)

0.67 kN

Maximum eccentricty

20 mm

(BS 8110 (1)-3.8.2.4)

Additional moment

0.01 kN.m

Adding this moment to the maximum bending moment due to transportation

Total Moment during Transportation

12.38 kN.m

Span/Depth Ratio Check

Basic Span/ eff. depth ratio

20 Service Stress

161 Modification Factor

2.00 Allow Span/ eff depth ratio

40.00 Actual Span /eff. depth ratio

17.88 O.K.

Reinforcement Calculations

Design Moment

M

12.38

kN.m/m

Concrete Strength

fcu

30

Steel Strength

fy

b

1000

mm

Depth of Section

h

200

mm

Bar Diameter f 10

mm

N/mm

2

f

_y

=

_N/mm

2

kN/m

2

kN/m

2

f

_s

=2/3 f

_y.

A

_{s req}

/A

_{s prov.}

N/mm

2

N/mm

2

(31)

Effective Depth

d

145

mm

Mu

98

kN.m

K

0.020

Lever-arm factor

La

0.98

La=Z/d

Lever-arm

Z

138

mm

Z= MIN(0.95d , La.)

As

206

As=M/(0.95 fy Z)

Asmin

260

Asmin= 0.0013.bh

No. of Bars Provided 5 T 10

As

393

Design Shear Force

V

19.08

kN/m

Concrete Strength

fcu

30

Steel Strength

fy

460

Width of Section

b

1000

mm

Depth of Section

h

200

mm

Bar Diameter f 10

mm

Clear Cover

Cc.

50

mm

Diameter of Link

No &

mm

Effective Depth

d

145

mm

Area of Main Steel

As

393

 0.271

V 0.13

Vc

0.56

Area of links

Asv

-Asv/Sv

-Spacing Required

Sv

Not reqd.

mm

d=h-Cc.-(

mm

2

mm

2

mm

2_/m

N/mm

2

N/mm

2 f of Link

d=h-Cc.-f

_L

-(

f/2)

mm

2

N/mm

2

N/mm

2

mm

2

(32)

LVC Chain A B C D E F G H I J K L M N

NO.11 4+390 2.10 2.40 0.70 0.45 0.35 #REF! #REF! #REF! #REF! 0.60 1.00 3.61 #REF! #REF! no shear key NO.12 6+035 2.10 2.40 0.70 0.45 0.35 0.78 1.20 4.80 5.70 0.60 1.00 3.15 0.60 0.50 no shear key

NO.13 7+265 2.10 2.40 0.70 0.45 0.35 1.50 1.50 6.25 6.30 0.60 1.00 4.30 no shear key

NO.14 7+425 NO.15 9+875