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

c = kN/m3

s = kN/m3

w = kN/m3

' =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..Bd2

1-e-2K

'(H/Bd)

' = tan '

K =

' - 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

- 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

=

' = tan '

=

2.K.'.(H/Bd) =

Cd =

(qr) = Cd..Bd2

(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 ' =

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

q max =

= x x

= kN/m2

qep = x x

= kN/m2

q = qmax - qep

q = kN/m2

1.403

101.0

Cd

1-sin

1+sin

1-sin

1+sin

0.406

7.2

2.K.'=

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

.Ka.h

Output

Civil Structure Maintanance Job Code Page 1

31.05.2010Designed S.M.P Date

Environmental & Checked

Reference Calculation

Date

C

E

B

Dam Safety

Ceylon Electricity Board Doc. No.

( = 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 = = qip.h2.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..h q1 = 2.G = kN/m2

= kN/m l.hw

Reinforced

Concrete = = q1.l2.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.c = kN/m2

C

E

B

Dam Safety Designed

9.81

16.68

Date

Page 2


S.M.P Date 31.05.2010

Environmental &

Doc. No.

1.7

2.21

3K+8

MA

{ }1.21

K+1

K+3

2K+3

2K+7

4.1

60.k1.k3

0.99

MC MD

K

4.21

5.43

9.43

11.64

MB

k7

1.217

8.2

MA MB

10.20

0.22


MC MD

-0.97

Checked

4.8

A B

D C

q = q1B.M.D

Pressures

A B

D C

qip

q = qipB.M.D

Pressures

A B

D C

q1

G G

B.M.DPressures

= = =

= q.l2

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 "qep" is the triangular pressure

4.2.1 Trianguler Pressure,qep

Reinforced

Concrete = = qep.h2.K.k7

Designers

Manual = kN.m/m

(ref-5.1)

= = MA. K8

= kN.m/m

4.2.2 Surcharge on walls,q

= = =

MC MD

Job Code

-0.91

Environmental &


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 +

Rooff

MA MB MC MD

-0.35

A and B 0.99 1.4 1.38 0.22

PositionHydrost-

aticf

uls-

MbWalls

-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-

Span0.99 1.4 1.38 0.22 1.04

Base mid-

Span1.22 1.4 1.70 2.35 1.4

**

0.821.53

**

2.83

3.29 5.00

**

1.4

1.40.82

-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

MA MB MC MD

Walls

middle1.4

4.2

0.26

k7

-1.13

MA MB

60.k1.k3

10

A B

D Cqepqep

B.M.DPressures

A B

D C

q = q1B.M.D

Pressures

Pressures

A B

D C

B.M.D

Reinforced = q.h2.K

Concrete 12.k1

Designers = kN.m/m

Manual 4.2.3 Surcharge on Roof ,qr

(ref-5.1) = = =

= q.l2

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 1.4Roof 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

PosotionL.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 13.589.70 1.38

1.22 12.02 15.12Base mid-

Span10.80

9.316.65 4.59Walls 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.)

14.96Roof 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

qep qWalls &

Roof(LC-1)

Surcharg -

e (Roof)

Total

(Survice)f Total U.L.S.

MA MB MC MD

-7.72

A B

D C

B.M.DPressures

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



Surcharge on Roof = kN/m2



Load Case -03



Surcharge on Roof = kN/m2

Hydrostatic 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


Date 31.05.2010

Environmental & Checked Date

10.20

C

E

B

Dam Safety Designed S.M.P


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 ok150

10.20

16.68

hence ok150

hence ok150

-22.70 14.96

-24.66 9.31

SaggingHogging

(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 /(1000x149

2x25)

= Minimum of 0.4% hence o.k.

100

1000 149

1.7

120 600

12 200

This is

0.40.759

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 OutputCalculation

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

box culvert design 2

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