Box Culvert Design 2

Figure 01 Dimentional Properties

= m

= m

Soil Cover , = m

Safe Bearing Pressure = kN/m2

Section Thickness

= m ( hw , h = span/(10 ~15))

Main R/F

= mm

Cover to R/F

= mm

Grade of Concrete

= N/mm2 Properties of Soil

γc

= kN/m3 γs = kN/m3

γw

= kN/m3 Φ' = o 1 - Permanent Loads Dead Loads

The nominal dead doad consist of the weight of the materials and the part of the structure

Structural Unit Weight of Concrete shall be taken as 24 kN/m3

Engineering Becouse of the arching of soil, check whether the depth above culvert is Design in > 3 x width of culvert ( in which case limit depth to 3 x width )

preactice

(Roger - Depth of cover (H) =

m

westbrook) 3 x width = 3 x (page-94) = m 3 x width

<

= m So

Depth limited to

=

m

Surcharge on Roof

Surcharge Presure (qr) = x qr = kN/m2

Soil

Engineering

Casses of conduit installation consider as Ditch Conduit

(Spangler &

Ditch Conduit

Handy)

A ditch conduit is defined as one which is instaled in a relatively narrow

ditch dug in passive or undisturbed soil and wich is then covered with earth backfill.

12

45

25

7.2 20 25 1.1 96

9.81

1.6

4.8

Reference

Calculation

7.2 1.2 1.5 0.2 7.2 150 h l

24

Output

Design of Box Culvert

4.8 20

4.8

Date

31.05.2010 Environmental &

Page

1

Ceylon Electricity Board

Doc. No.

C

E

B

Dam Safety

Designed

S.M.P

H

Reference

Calculation

Output

Checked

Date

Civil Structure Maintanance

Job Code

Y hs hw Ground Level hs hw A B D C H l h X

Maximum load on ditch condition Depth of cover = m

Surcharge on Roof

Surcharge Presure (qr) , (qr) = Cd.γ.Bd 2

1-e

-2Kµ

'

(H/Bd) µ' = tan φ'

K

=

µ' -

coedicient of friction between fill material

and side of ditch

K

-

Active Lateral earth pressure coeficient Bd -

Horizontal width of ditch at top of conduit

γ

-

Unit weight (wet density) of filling material

H

- Height of fill above top of conduite

Cd - Load coeficient for ditch condition

So, K = Bd = m, Consider 1m length of Roof slab

= µ' = tan φ' = 2.K.µ'.(H/Bd) = Cd = (qr) = Cd.γ.Bd 2 (qr) = kN/m2

Structural Horizontal Earth Pressure Engineering

Design in If the backfill properties are known, preactice If wall friction is to be ignored (Roger

-westbrook) K0 = 1-sin Φ' =

(page-94) Ka = ( 1-sin Φ' ) / ( 1+sin Φ' ) =

q max

=

=

x

x

=

kN/m2

q

ep

=

x

x

=

kN/m2

q

= q

max

- q

ep

q

=

kN/m2

1.403

101.0

Cd

1-sin φ

1+sin φ

1-sin φ

1+sin φ 0.406 7.2 2.K.µ' = 0.466 0.76 3.60

20

0.41

0.577 0.406

15.42

9.1

73.9

20

0.41

1.9

58.44

γ.Ka.h

Output

Civil Structure Maintanance

Job Code

Page

1

31.05.2010

Designed

S.M.P

Date

Environmental &

Checked

Reference

Calculation

Date

C

E

B

Dam Safety

Ceylon Electricity Board

Doc. No.

(δ = 0 ) 1.2

AASHTO 2 - Vertical Live Loads 3.7.1

For Fill Depths H ≥ 8 feet (2400 mm) and Culvert Clear Span Length,

The effect of live load is neglected in design when the depth of fill is more than

8 feet

3 - Hydrostatic Pressure (Internal)

q

ip

= C.h

=

x

=

kN/m2

4 - Analysis Reinforced Concrete Constant K = h hs 3 = Designers l hw Manual k1 = = (ref-5.1) k3 = = k5 = = k7 = = k8 = =

Load Case -01 Testing Condition 4.1.1

Hydrostatic Pressure-(Internal)

Reinforced

=

= q

ip

.h

2

.K.k7

Concrete Designers

=

kN.m/m

Manual (ref-5.1)

=

= Ma. K8

=

kN.m/m

4.1.2

Flexure due to weight of wall

Wall weight ( G ) = hw.γ.h

q1 = 2.G

=

kN/m2

= kN/m

l.hw

Reinforced Concrete

=

= q1.l

2

.K

Designers

12.k1.k3

Manual

=

kN.m/m

(ref-5.1)

=

= Ma. K5

=

kN.m/m

4.1.3

Flexure due to weight of Roof

q = hs.γc =

kN/m2

C

E

B

Dam Safety

Designed

9.81

16.68

Date

Page

2

Reference

Calculation

Output

S.M.P

Date

31.05.2010 Environmental &

Doc. No.

1.7

2.21 3K+8

M

A

{

}

1.21 K+1 K+3 2K+3 2K+7 4.1

60.k1.k3

0.99

M

C

M

D

K

4.21 5.43 9.43 11.64

M

B

k7

1.217 8.2

M

A

M

B 10.20

0.22

Civil Structure Maintanance

Job Code

M

C

M

D

-0.97

Checked

4.8 A B D C q = q1 B.M.D Pressures A B D C qip q = qip B.M.D Pressures A B D C q1 G G B.M.D Pressures

=

=

=

= q.l

2

12.k1

=

kN.m/m

Addition of moment for Load case 01

Table - 01 Fixed end mement of the wall for Hydrostatic load

MA = MC =

= kN.m/m = kN.m/m

Maximum (-ve) moment =

(Where x is 0.45L from C)

= kN.m/m

* Calculation of moment at mid span of walls done by aproximatly by adding moment transferred to mid span from FEM to the Maximum negative meoment occurred at 0.45L after moment distribution

** Moment at mid span of the wall is calculated by considering full bending

Calculation of midspan moment due to wall load Niutral axis depth from A = m

Load Case -02 Culvert empty and trench filled

Lateral soil pressurees giving rise to flexture in the structure

"q"is the rectanguler pressure and "q

ep"

is the triangular pressure

4.2.1

Trianguler Pressure,q

ep Reinforced Concrete

=

= q

ep

.h

2

.K.k7

Designers Manual

=

kN.m/m

(ref-5.1)

=

= M

A

. K8

=

kN.m/m

4.2.2

Surcharge on walls,q

=

=

=

M

C

M

D

Job Code

-0.91

Environmental &

Reference

Calculation

Output

Checked

Date

Civil Structure Maintanance

Page

3

Doc. No.

C

E

B

Dam Safety

Designed

S.M.P

31.05.2010

-2.06

*

uls-Mb

Total

uls

-0.35 Roof

Date

23.3 Walls + Roof

γf

M

A

M

B

M

C

M

D

-0.35

A and B

0.99

1.4

1.38

0.22

Position

Hydrost-atic

γf

uls-

Mb

Walls

-0.14 1.4 -0.19 1.19 C and D

1.22

1.4

1.70

-0.97

-0.35 -1.32 1.4 -1.85 -0.15 Roof mid-Span

0.99

1.4

1.38

0.22

1.04 Base mid-Span

1.22

1.4

1.70

2.35 1.4

**

0.82

1.53

**

2.83 3.29 5.00

**

1.4 1.4 0.82 -1.02 -1.0 1.607 W.L -0.35 -0.73 1.45 W.L 2.41

-2.88

-0.38

-3.90 15 W.L

M

A

M

B

M

C

M

D Walls middle

1.4

4.2 0.26

k7

-1.13

M

A

M

B

60.k1.k3

10 A B D C qep qep B.M.D Pressures A B D C q = q1 B.M.D Pressures Pressures A B D C B.M.D

Reinforced

= q.h

2

.K

Concrete

12.k1

Designers

=

kN.m/m

Manual 4.2.3

Surcharge on Roof ,qr

(ref-5.1)

=

=

=

= q.l

2

12.k1

=

kN.m/m

Addition of moment for Load Case 2

Fixed end mement of the wall due to qep

MA = MC =

= kN.m/m = kN.m/m

Maximum (-ve) moment =

(Where x is 0.45L from C)

= kN.m/m

Load Case -03

4.2.1

This is load case 02 + Hydrostatic load from Load case 01

5 - Check on ground safe bearing pressure Load Case -01 1.486 2.229 W.L 23.3 -1.0 1.43 13.39 -7.45 6.65 1.4 9.31 W.L W.L

*

**

13.58 -1.13 -7.72 2.35 17.29 10.80 15.12 -0.91 -7.72 1.04 17.29 9.70 1.4 Roof mid-Span Base mid-Span -0.91 -7.72 -0.14 -7.45 -1.13 -7.72 1.4 -22.70 -17.62 1.4 -24.66 -16.22 1.4 Posotion -1.32 -7.45 A and B C and D Posotion L.C.02 (Service) 4.2

Calculation

Output

5.1 1.22 -16.40 -24.66 Hydrost. (Service) Total (Service) L.C.02 (U.L.S.) 1.70 -2.06 C and D -17.62 1.70 0.99 10.69 13.58 9.70 1.38 1.22 12.02 15.12 Base mid-Span 10.80 9.31 6.65 4.59 Walls middle Total (U.L.S.) A and B -16.22 1.38 -21.32 -22.96 0.99 -15.23 -22.70 Hydrost. (U.L.S.) 14.96 Roof mid-Span

S.M.P

Doc. No.

Date

31.05.2010 Environmental &

Reference

Designed

Civil Structure Maintanance

Job Code

Page

4

C

E

B

Dam Safety

Checked

Date

Walls middle -0.73 15 10 -2.88 6.43 16.83

-7.45

q

ep q Walls & Roof(LC-1) Surcharg -e (Roof) Total

(Survice) γf Total U.L.S.

M

A

M

B

M

C

M

D

-7.72

A B D C B.M.D Pressures Pressures A B D C B.M.D

Hydrostatic Pressure = kN/m2

Weight of walls = kN/m2

Weight of Roof + Floor = kN/m2

Total Pressure = kN/m2

Total Pressure <

kN/m2

Load Case -02

Weight of walls = kN/m2

Weight of Roof + Floor = kN/m2

Surcharge on Roof = kN/m2

Total Pressure = kN/m2

Total Pressure <

kN/m2

Load Case -03

Weight of walls = kN/m2

Weight of Roof + Floor = kN/m2

Surcharge on Roof = kN/m2 Hydrostatic Pressure = kN/m2 Total Pressure = kN/m2 Total Pressure <

kN/m2

6 - U.L.S. of Flexture Maximum Moments kN.m/m i - Slabs Maximum Moment = kN.m/m

6 -

Design Calculation for Box Culvert

U.L.S. of Flexture

Analysis was carried out for several load cases of various loading 9.60

6.1

Page

5

Reference

Calculation

Output

Date

31.05.2010

Environmental &

Checked

Date

10.20

C

E

B

Dam Safety

Designed

S.M.P

Civil Structure Maintanance

Job Code

96.00 122.28

Doc. No.

16.68 9.60 96.00 5.2 115.80 5.3 10.20 9.60 36.48 hence ok 150 10.20 16.68 hence ok 150 hence ok 150 -22.70 14.96 -24.66 9.31 Sagging Hogging (L.C-03) (L.C-02) -24.66 16.83 24.15 Walls Base Member (L.C-03) (L.C-01) (L.C-02) (L.C-02) Roof

arrangements to find out the maximum effect on the Box culvert

Diameter of main reinforcement =

mm

Diameter of secondary reinforcement =

mm

Section Thickness

=

mm

Maximum Bending Moment

=

kN.m/m

Assume severe environment condition, for driving rain

Cover =

mm

Effective depth, d = - 45- 6 d =

=

k = M / (bd2fcu) 2 = (24.15x106 /(1000x1492x25) = <

Hence no compression r/f is required

M = (0.87fy)Asz equation 1

z = (1 - 1.1fyAs/ fcubd) d equation 5 from these two equations

z = d (0.5+(0.25-k/0.9)1/2 z = d [0.5+(0.25-0.044/0.9)1/2 = < _d Take Z as 0.95d Z = d = x =

mm

Design of main reinforcement As = M / 0.87fyz = 24.15 x106 / 0.87x460x142 As req = =

mm

2

/m

mm2/m Use T @ ( As =

_mm

2

/m

A

s pro = mm2/m Minimum area of main rainforcement for slabs

100As / bad = 100x452/(1000x149) = ## Main r/f

T @

Hence o.k

Design for Shear Reinforcement

Check shear in U.L.S. on roof and floor slabs

Take Load case 02

Shear across support

=

(

-

Wt of Base x γf )

=

kN/m2

Therefore shear in the support =

x

1.2 /2

=

kN/m

Design shear force, V design = kN/m

Effective depth, d =

mm

Tension steel across shear plane = Y12 -250 c/c

100 As/bd

=

24.15

100 x 452

6.2

Reference

Calculation

C

E

B

149

Civil Structure Maintanance

Job Code

Page

65.45

6

Output

45

Environmental &

Checked

Date

Doc. No.

12 12

200

149 mm 149 mm 0.156 0.950 200 0.95 0.95 149 142 141.41 6.1.1 0.30 0.13

0.044

426 12

250

452 426 452

109.08

109.08

65.45

12

Dam Safety

Designed

S.M.P

Date

31.05.2010

250

=

BS 8110 Effective depth

=

mm

Part 01

v

c

= 0.79x{(100As/bd)

1/3.

(400/d)

1/4

/1.25

table 3.1

=

Design shear stress v = V/bd

= (65.45x103)/(1000x149)

=

v

<

vc

Hence o.k

Check in U.L.S. on the ability of the wall to trasmit the axial loads Bs 8110 Treat as a column with bending at right angle to wall

3.9.3.6.2

Check h/hw

=

/

3.4.4.1

=

<

hence column is short

BS 8110 indicates that the effect of the axial load may be ignored if this force does not exceed 0.1.fcu.(

c.s.a.)

hence

0.1.fcu.(C.S.A)

=

x

x

= kN/m

Ultimate Load /m/Wall = x x 1.4

+ x x 24x1.4 )

= kN/m < kN/m

hence o.k.

The above calculation assumes that the wall is cosidered as reignfoced and not mass concrete

vertical R/F provided = Y @ 2 Layers

so Area = mm2

Percentage of Concrete area = x

x

= % > %

> Minimum of 0.4% hence o.k.

100 1000 149 1.7 120 600 12 200 This is 0.4 0.759

12

0.1

30

8.5

0.2 1131.0 1131.0

1.7

0.44 Dam Safety

200

600

C

E

B

1.7

Reference

Calculation

Output

Date

N/mm2

7

Designed

Page

0.2

31.05.2010

Checked

Job Code

S.M.P

Date

0.30

149

0.54

Doc. No.

1000x149

1/2( 96.0 Environmental &

Civil Structure Maintanance 6.3

Job Code

Page

8

Dam Safety

Environmental &

Civil Structure Maintanance

C

E

B

Designed

S.M.P

Date

Doc. No.

Checked

Date

31.05.2010