Culverts

• What is a Culvert?• Culvert Components• Culvert Design and Construction• Culverts – Pros / Cons

Culverts

What is a Culvert?

Culverts

CHBDC• Buried Structure• Bridged Opening – 3m span• Design – soil interactionAT• Surrounded by Soil• Below Road• Parallel to Stream• >= 1.5m DIA flow area

Culverts

Culvert Components

Culverts

Invert Streambed

Road

Rock

Bevel End

Cover

Burial(Embedment)

Elevation View

Crown(Obvert)

Clay Seal

Inlet Outlet

Barrel

Culverts

Plan View

Culverts

XS View

Rise

Span

Road

Burial(Embedment)

Cover

Haunch

CulvertsCulvert Shapes

EllipseRound

Arch Box

Culverts

Arch

Box

Round

Ellipse

Arch

Box

Round

Ellipse

Culvert Shape in AT System

Round

Ellipse

ArchBox

All (~2820) > 1999 (~380)

Ellipse BoxArch

Round

CulvertsCulvert Materials

SPCSPCSP

CIP PC Plastic

WSP

Culverts

Slide 11

CulvertsCulvert Material in AT System

CIP

Precast

CSP

SPCSP

WSP

Plastic

SPCSP

CSP

CIP PC

PlasticWSP

CulvertsCulvert Size in AT System

0

10

20

30

40

50

60

70

80

90

100

1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5

Perc

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f Str

uctu

res

Pipe Diameter (m)

CulvertsCulvert Age in AT System

0

10

20

30

40

50

60

70

80

90

100

1950 1960 1970 1980 1990 2000 2010 2020

Perc

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Year

Culverts

Culvert Design and Construction

CulvertsSoil Steel Structures – No backfill

CulvertsSoil Steel Structures – Compacted backfill

Culverts• Wide, Low Cover• Acts like Bridge• Costs like Bridge

Culverts

Pipe Arch

• High Stress• Compaction??

• Low Resistance• Bulging

Culverts

Culverts

OpenBottom

Culverts

Culverts

CulvertsBase Preparation

Culverts

NO CAMBER

CulvertsAssembly – Side Plates

CulvertsAssembly – Roof Plates

Check Dimensions Control Shape

CulvertsBackfill - Haunch

CulvertsBackfill - Sides

CulvertsConcrete End Treatment

Culverts

Culvert – Pros / Cons

CulvertsCost

Culvert = $1000/m2 * pi * L * DBridge = $4000/m2 * L * W

Culvert Bridge Ratio

D L Cost L W Cost

2 40 250,000 14 10 560,000 0.45

3 40 375,000 15 10 600,000 0.63

4 40 500,000 16 10 640,000 0.78

5 40 625,000 17 10 680,000 0.92

Culverts

Bridge Preferential Icing

Culverts

Bridge Barriers

Culverts

Unstable Valley Walls

Culverts

Need Soil Support

Culverts

Channel Work

Culverts

Blockage - Drift/Icing

Culverts

Pros ConsCost Need Soil SupportPreferential Icing Channel WorkNo Barriers Drift, IcingUnstable Valleys

Hydraulics, Fish Passage ????

Note: Selection of crossing structure is based on an optimization process involving assessment of a range of options (see Bridge Conceptual Design Guidelines)