ANALYSIS OF BOX TYPE MULTI- BARREL SKEW CULVERT

© 2018 JETIR April 2018, Volume 5, Issue 4 www.jetir.org (ISSN-2349-5162)

JETIR1804227 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 1

ANALYSIS OF BOX TYPE MULTI-

BARREL SKEW CULVERT

Virendrasinh . D. Chauhuan1, Gunvant Solanki

2, Minu Tressa

3

1Post-Gradution student, Department of Civil Engineering, CGPIT Collage, UTU, Bardoli, Gujarat, INDIA

2Assistant Professor, Department of Civil Engineering, CGPIT Collage, UTU, Bardoli, Gujarat, INDIA

32Assistant Professor, Department of Civil Engineering, CGPIT Collage, UTU, Bardoli, Gujarat, INDIA

Abstract-As the numbers of bridges comes up it has become healthy to provide box type multi-barrel skew

culvert where traffic moves on the top of continuous slab and water flows through barrels underneath it. Present

situation of traffic requirements demand straight alignment of road in view of the fast traffic and this in turn

necessities the use of skew crossings. By providing this type of alternatives, bridge span is in direction of road,

we can directly provide skew culvert. So, there is no need for provide approaches on both side in form of curve

which will solve land acquisition problem and project becomes faster and economical.

Modelling and analysis of the skew bridge deck and box is to be done in STADD PRO and/or in SAP.

For single cell analysis separate worked out manually with considering all load combination guided in IRC-6.

The problem consisting of two lane road width (7.5m) and span of 20m. Each barrel is dimension has 5m by 5m.

For dead load, live load, earth pressure, water pressures are considering and for various load combination it will

be analysed and for critical design will be made. For analysis, Culvert is designed for 0degree skewness for

single, two, three and, four barrels. Further comparative study is carried out for different skew angles 10degree,

20degree, 30degree, 40degree, 50degree and, 60degree.Parametric study also done for the given problem

statement by considering various skew angles for comparing bending moments. Another study done for different

support condition on base slab.

Keyword: Culvert, multi-barrel box culvert, Skew culvert, STADD PRO

1.INTRODUCTION 1. GENRAL

A bridge is a structure which maintains communication such as the road and railway traffic and other moving

loads over an obstacle, namely channel, river or a valley. The structure is termed as a bridge when it carries a

road and railway traffic or pipe line over a channel or a valley and an Overbridge when it carries the traffic or

pipeline over a communication system like roadways or railways.

2. CLASSIFICATION OF BRIDGE

The classification of bridge structures with reference to the size has been done differently by road and rail

alignment. The Indian railways consider structures having any span of clear waterway of 12 m or over as a

major bridge and those below as a minor bridge. For the purpose of investigation and cross drainage structures

can be grouped into three categories as follows,

1. Culvert and Minor bridge (linear water way up to 30m).

2. Major bridge (lineal waterway over 30 m but on stable rivers and canals).

3. Important bridge (lineal waterway over 30 m but on major rivers or tributarieswhich are shifting in nature).

3. culvert

A culvert is a bridge like structure designed to allow vehicle or pedestrian traffic to cross over the waterway

while allowing adequate passage for the water. Culverts are commonly used for ditch relief and also to pass

water under a road at natural drainage and stream crossings. Culverts come in many sizes and shapes including

round, elliptical, flat-bottomed, and box-like constructions.



According to construction a culverts are classified as follows,

- Slab culvert

- Pipe culvert

- Box culvert

BOX CULVERT

Box culvert is ideally suitable monolithic structure across a highway, railway embankment, which consist top

slab, bottom slab and two vertical side walls.

If the discharge in a drain or channel crossing a road is small, and if the bearing capacity of the soil is low, then

a box culvert is an ideal bridge structure. A box culvert is consisting of an RCC box of square or rectangular

opening. The top of the box is road level or it may be at a depth below the road level if the road is an

embankment. If the design discharge is considerable, a single box culvert becomes uneconomical because of the

higher thickness of the slab and walls. In such cases, more than one box cast side by side monolithically.

Box culvert is economical for the reasons mentioned below:

The box is a rigid frame structure and both the horizontal and vertical members are made of a solid

slab, which is very simple in construction.

In case of high embankments and ordinary culvert will require very heavy abutments that will not only

be expansive but also transfer heavy loads to the foundations.

The box type of structure is suitable for non-perennial streams where scour depth is not significant but

subgrade soil is weak.

The dead load and superimposed load are distributed almost uniformly over a wider area as the bottom

slab serves as a raft foundation, thus reducing pressure on soil.

4. NEED OF SKEW CULVERT

Skew bridges are necessary when a stream crosses the road at an angle different from 90 degree. Present

situation of traffic requirements demand straight alignment of road in view of the fast traffic and this in turn

necessities the use of skew crossings. Bridges in plane form is a parallelogram; the angle obtained subtracting

the acute angle of parallelogram from 90degree is termed as skew angle.

Figure 0-1 Box culvert Figure 2 Pipe culvert



5. Highway bridge loading

The following forces shall have to be considered in the design of road bridges and all members shall be designed

to sustain safely the effect of various loads, forces and stress that may act together.

1. Dead Load

2. Live Load (Consider 70R tracked vehicle)

3. Impact Load

4. water Current

5. Earth Pressure

6. Seismic Forc

2. Analysis of box type multi-barrel skew culvert

In present study consists of single, two, three and, four span of box type skew culvert at different skew angle

varies from 0 degree to 60 degree at 10 degree interval for analysis. The modelling is done in STADD.pro.

PROBLEM STATEMENT

For sample calculation only single culvert is consider,

Span of a culvert 5 m

Width of carriage way 7.5 m

Footh path 250 mm x 1200 mm

Height of box 5 m

Width of box 5m

Top slab thickness 500 mm

Bottom slab thickness 700 mm

Thickness of side wall 450 mm

Thickness of wearing coat 80 mm

Co-efficient of earth pressure 0.5

M-20 concrete, Fe-415 Steel should be consider.

Figure3 Skew crossing



1. MODELLING STEPS FOR A BOX CULVERT IN STADD.PRO

STADD.pro having nice facility to Model Bridge very easily. It is having step by step bridge modelling option.

First select the units in which all the loads to be given. Here for three-dimensional modelling global

system is selected and kN.m units selected. Then geometry of the modelling will be started.

The second

step is, develop a

geometry of multi-

barrel box culvert.

Figure 4 single span box culvert

Figure 5 Bridge wizard in STADD.pro

Figure 6 Geometry development for multi-barrel skew culvert



Third step is to assign the property to the box culvert.

The

four step is

assign a support

art base.

The fifth step is assign a load, which acting on a culvert.

Figure 7 Assign property to box culvert

Figure 8 Assign support at base

Figure 9 Assign D.L & L.L on top and bottom slab



Figure 10 Water pressure acting inside a culvert

Figure 11 Earth pressure due to earth fill

Figure 12 Earth pressure due to surcharge

Figure 13 Earth pressure acting at base



3.RESULT

1. DIFFERENT SKEW ANGLES COMPARISONS WITH BENDING MOMENT

A bending moment at a base slab of a culvert is find out for a Dead load, Live load, Earth Pressure and,

water pressure for a various skew angle 0degree to 60degree for a single, two, three and, four span box

culvert.

41

.23

26

.98

24

.83

26

.52

37

.04

36

.51

36

.11

14

2.6

2

98

.66

93

.39

82

.14

12

7.3

2

12

5.2

8

12

3.8

1

17

.76

5.3

9

2.1

2

0.1

04 16

.51

16

.49

16

.45

19

.37

5.8

8

2.2

4

0.8

6 18

13 1

7.9

5

0 1 0 2 0 3 0 4 0 5 0 6 0

BEN

DIN

G M

OM

ENT,

kN

.m

ANGLE OF SKEW (DEGREE)

BENDING MOMENT AT BASE SLAB

Dead Load Live Load Earth Pressure water Pressure

Figure 14 : Bending moment diagram for single span culvert

18

.23

15

.14

2

17

.03

5

15

.84

15

.62

16

.84

17

.31

79

.1

57

.04

64

.47

59

.02

59

.32

63

.14

64

.78

1.2

3

1.1

2

0.9

2

1.9

1

2.0

6

1.6

7

1.7

6

1.3

4

1.2

2

1.0

1

1.2

8

2.2

5

1.8

2

1.9

20 1 0 2 0 3 0 4 0 5 0 6 0B

END

ING

MO

MEN

T, k

N.m


BENDING MOMENT AT BASE SLAB


Figure 15 : Bending moment diagram for two span culvert

15

.71

12

.11

14

.18

12

.51

13

.07

13

.55

13

.92

65

.53

46

.65

54

.69

48

.23

50

.23

51

.89

53

.1

2.2

3

1.5

8

1.1

5

2.3

6

2.4

1

2.4

3

2.4

4

2.4

4

1.7

3

1.2

5

2.5

8

2.6

3

2.6

6

2.6

7

0 1 0 2 0 3 0 4 0 5 0 6 0

BEN

DIN

G M

OM

ENT,

kN

.m


BENDING MOMENT AT BASE


Figure 16 : Bending moment diagram for three span culvert



2. DIFFERENT SKEW ANGLES CMPARISONS WITH DISPLACEMENT

A maximum displacement of a culvert is find out for a various skew angle 0degree to 60degree for a

Single, Two, Three and, Four span.

15

.71

12

.11

14

.18

12

.51

13

.07

13

.55

13

.92

65

.53

46

.65 54

.69

48

.23

50

.23

51

.89

53

.1

2.2

3

1.5

8

1.1

5

2.3

6

2.4

1

2.4

3

2.4

4

2.4

4

1.7

3

1.2

5

2.5

8

2.6

3

2.6

6

2.6

7

0 1 0 2 0 3 0 4 0 5 0 6 0

BEN

DIN

G M

OM

ENT,

kN

.m


BENDING MOMENT AT BASE


Figure 17 : Bending moment diagram for four span culvert

2.5

1.8

2

2.0

3 2.3

2.6

7 3.0

2 3.3

4

0 1 0 2 0 3 0 4 0 5 0 6 0

DIS

PLA

CEM

ENT,

mm


DISPLACEMENT

Figure 18 : Displacement diagram for single span culvert

1.2

1

0.6

9

1.1

1 1.2

8 1.4

9 1.7

1.8

9

0 1 0 2 0 3 0 4 0 5 0 6 0

DIS

PLC

EMEN

T, m

m


DISPLACEMENT

Figure 20 : Displacement diagram for three span culvert



3.PARAMETRIC STUDY FOR A VARIOUS

BASE SLAB RIGIDITY

Normally base slab support condition, outer wall is

considered as fixed and internal wall considered in

hinged condition. So, considering base slab as

parameter two different support conditions will be

considered. One support condition in which

external wall having fixed support and internal

walls having hinged condition while on the other

hand whole base slab is resting on elastic

foundation ( Providing spring support).The bending moment and a

displacement are find out for a three span and four span box

culverts for a Dead load and Live load for both

support condition.

6.0

7

3.3

5

3.0

33

3.3

8

7.6

2 8.4

5 9.2

2

0 1 0 2 0 3 0 4 0 5 0 6 0

DIS

PLA

CEM

ENT,

mm


DISPLACEMENT

Figure 19 : Displacement diagram for two span culvert

1.7

4

1.2 1.3

1

1.4

6 1.9

5

1.7

2

1.7

7

0 1 0 2 0 3 0 4 0 5 0 6 0

DIS

PLA

CEM

ENT,

mm


DISPLACEMENT

Figure 21 : Displacement diagram for four span culvert

65

.53

46

.5 55

48 50 52 53

70

47

56

49 52 5

9 64

0 1 0 2 0 3 0 4 0 5 0 6 0

BEN

DIN

G M

OM

ENT,

kN

.m


BENDING MOMENT

Spring Support Fixed Support

Figure 22 Bending moment diagram for three span culvert due to live load

42

27

.5

35 37 39 39

.8

4142

.5

28

38 39 40

40 42

0 1 0 2 0 3 0 4 0 5 0 6 0

BEN

DIN

G M

OM

ENT,

kN.m


BENDING MOMENT

Spring Support Fixed SupportFigure 23 Bending moment diagram for four span culvert due to live load



1.7

4

1.2 1

.31

1.4

6

1.9

5

1.7

2

1.7

7

1.8

2

1.2

7

1.4

2 1.6

2 1.8

8 2.1

4 2.3

8

0 1 0 2 0 3 0 4 0 5 0 6 0

DIS

PLA

CEM

ENT,

mm


DISPLACEMENT

spring support fix support

Figure 24 Displacement diagram for three span culvert

1.2

1

0.6

9

1.1

1

1.2

8 1.4

9 1.7 1

.89

1.2

4

0.7

1 1.1

12

1.2

86 1.6

18

1.8

9

2.0

20 1 0 2 0 3 0 4 0 5 0 6 0

DIS

PLA

CEM

ENT,

mm

ANGLE OF SKEW (DEREE)

4 SPAN DIS

spring support fix support

Figure 25 Displacement diagram for four span culvert

58

0

39

5

37

0

33

0

51

0

50

0

49

5

0 1 0 2 0 3 0 4 0 5 0 6 0

AST

REQ

UIR

ED, m

m2


A S T REQUIRED PER METER

Figure 26 Ast required per meter for a single span culvert



4 Conclusion

From the analysis, we conclude that the value of a bending moment at a base slab for single,

two, three and, four span culvert decreases with increase in a skew angle up to 30degree and

then increases up to 60degree, but which is less then the value at normal culvert. Thus, reduce

the thickness of a base slab.

The value of a displacement for a culvert decreases with increases in the skew angle up to 30

degree and then increase up to 60 degree, but which is in permissible limit (20mm).

From the result we conclude that, value of a bending moment and displacement for a spring

support condition is less then the value at a fix support condition so, if we consider a base slab

on elastic foundation, we reduce the base slab thickness. Thus reduce in the cost of concrete.

From the table we conclude that, area of steel required per meter for a single, two, three and,

four span culvert decreases with increases in skew angle. Thus we can save a steel cost and

project becomes economical.

From the analysis we conclude that if we provide a culvert at a required skewness up to 60

degree ,there is no need to provide a approaches on both side in the form of curve, which will

solve land acquisition problem and project become faster and economical.

5. REFERENCES

[1] S. B.V and D. S.V, “EFFECT OF SKEW ANGLE ON STATIC BEHAVIOUR OF RAINFORCED

CONCRETE SLAB BRIDGE DECK,” International Journal of Research in Engineering and Technology,

pp. 50-58, 2013.

[2] H. Muhammad and N. Sakthieswaran , “Dynamic Response of Skewed Multi-Span Steel Composite

Bridge,” International Research Journal of Engineering and Technology, vol. 03, no. 014, pp. 2316-2320,

2016.

[3] M. Jun and . H. G, “Analytical and experimental study of skew bridge model,” Engineering Structure , vol.

26, pp. 1127-1142, 2004.

[4] l. Eric and M. Jun, “Seismic analysis and assessment of skew highway bridge,” Engineering Structure, vol.

22, pp. 1433-1452, 2000.

[5] S. Dr. and k. vinod, “ANALYSIS AND DESIGN OF BOX CULVERT USINGCOMPUTIONAL

MEHOD,” International Journal of Engineering & Science Research, vol. 5, no. 7, pp. 850-860, 2015.

[6] K. N and M. Molly, “ANALYSIS AND DESIGN OF RCC BOX CULVERT,” International Journal of

Scientific & Engineering Research, vol. 5, no. 12, pp. 36-40, 2014.

Documents

ANALYSIS OF BOX TYPE MULTI- BARREL SKEW CULVERT