PIPE CONSTRUCTIONOhio Department of Transportation

Corrugated Metal Pipe InstallationBrian Flint

Regional Engineer

CONTECH CONSTRUCTION PRODUCTS, INC.

What is There to Talk About ?

• Materials– Corrugations & Gauges – Coatings

• Structural Design• Foundation Considerations• Backfill Procedures• Proper Cover Requirements• CSP Joint Options

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Corrugated Metal Pipe Design Criteria

• Hydraulics– Can You Achieve the Flow Requirements

• Structural Capacity– Can You Handle the Loading Condition

• Durability– Can You Last 75 Years

– Prove It !

• Economy

Structural Design

1. Determine the loads on the pipe.

2. Calculate ring compression.

3. Perform basic strength and stiffness checks.

a) wall strength

b) seam strength

c) handling stiffness

4. Ensure minimum cover.

5. Check and account for corner pressures on multiple radius pipes. (i.e. pipe arches)

Physical Strength

• Structural Design

• Installation Stiffness– Importance of a Quality Backfill

Deflection: Modified Iowa Formula

Deflection = Load

Pipe Stiffness + Soil Stiffness

Soil Stiffness Accounts for 90% of Total Stiffness

Approved ODOT Sizes

• CONTECH size range from 6 “ to 144 “.

• ODOT Sizes:• 707.01 1/4” or 1/2” deep 6” - 84”

• 707.02 1” deep 36” - 120”

• 707.12 Spiral Rib 18” - 78”– ALUMINIZED Steel Type 2 Only

• 707.08 and 707.09– Fiber Bonded CSP No Longer Available !

Durability

• How Long Should it Last ?• 50 years or 75 years

• What is the Design Service Life Required ?• ODOT has Durability Charts for Metal Pipe

– L & D Manual: 1002-5 and 1002-6

• ALT2 provides a minimum of 75 years for 16ga when 5<pH<9 and R>1500. As the gage is increased, the service life increases.

MANUFACTURER

TYPE OF COATING

GAUGE

HEAT NUMBER

DATE OF MANUFACTURE

SPECIFICATIONS

• Unloading and Handling• Basic Installation• Bedding• Backfill• ULTRA FLO (Spiral Rib)• Connections/Bands/Accessories

Installation Overview

Unloading and Handling

• Easily shipped in “nested” bundles (fewer trucks)

• Easy to handle and unload:

– Light weight ( light equipment )

• Lifting Lugs for Large Diameter

– used with slings and hooks

• Slings or fork lift for smaller Diameter

• DO NOT Roll off truck

– Long Joints ( 20 ft - 40 ft )

– Small outside Diameter

Proper Bedding

• Uniform Support– Lateral– Longitudinal

• Well graded granular material• Free of frozen soil, sod, and large rocks• Upper few inches should be relatively loose to

allow corrugations to seat in bedding

Proper Foundation

FirmSoft

Pipe

Uneven Foundation

Pipe

Uniform Foundation

Soft Foundations

Soft In-Situ Soil

W

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Soft Soft

Shape Bottom For Pipe Arch

For pipe-arch, excavate under pipe and replace withgranular material only as deep as is necessary toobtain stable bed to install pipe

Excavate Soft Soiland Replace with Highly compacted granular material

Minimum Permissible Spacing For Multiple Installations

Arches

Pipe Arches

SpanSpan

PipeDiameter Diameter Span

Up to 36”……..12”36” to 108”……1/3 span108” to 189”…..36”

Diam.Up to 24”…..12”24” to 72”….1/2 diam.72” and over..36”

Backfill

• Satisfactory material:

– Well graded granular, w/ little to no plasticity

– Clean/dense/stable/drainable soil

• Proper placement (6”- 8” lifts on each side)

• Proper Compaction (90% Std. Density)AASHTO T99

• Maintain minimum Height of Cover

• Installation conditions: – Embankment or Trench

Proper Backfill - Embankment

8” Lifts

Thoroughly compact fill in 8” max loose lifts. Keep fill at same level on both sides of pipe.

Diameter

Lifts Should extend at least 1 pipe diameter on each side

Proper Backfill - Trench

8” Lifts

Outside diameter plus sufficient roomfor compaction equipment

Diameter

Tamping Under the Haunches

SpanDiameter

Tampered Fill

Care must be taken to assure that voids and soft spotsare not left under the haunches of pipe

Proper Backfill: Pipe Arches

SpanCompacted Layers

in 8” Lifts

Compacted to max density below and beside the haunches

Stable

Heavy Construction Loads

Finished Grade

Height of Cover

Temporary Cover forConstruction Loads

Pipe

Compaction Techniques

• Walk Behind Compactor

• Sheep Foot or Rubber Tire Roller

• Vibrating Rollers

• Flooding with Water

– approved ODOT methodology

Bands and Accessories

• HUGGER® Band– Bolt Bar and Strap Connector– O Ring Gaskets

• Flat Band– Flat Gasket

• STAB Joint– Fluted Gasket

• Dimple Band

• Easy to assemble

• Positive Joint, w/ pull apart resistance

• Soil tight

• Can be done with 1 or 2 people

• Small amount of tools

– Felton Band Puller

– Mallet

– Open end or Deep socket wrench

– Impact Equipment

Your Greatest Strength Can be Your Greatest Weakness

Band Fasteners

• Scafco Angle– Used for smaller Diameter Pipe

• Bar, Bolt and Strap– Single – Double

• Rod and Lug (Levee Band Applications)

HUGGER Band

12-1/8”10-1/4”

H-12 HUGGER

BAND

H-12 HUGGER

BAND12-1/8”10-1/4”

O-RingGasket Gasketed

Section

Connection DetailSingle

Bolt, Bar, & Strap

HUGGER Bands

• Bands are normally furnished as follows:– 12” thru 48” 1 piece– 54” thru 96” 2 piece– 102” thru 144” 3 piece

• Band fasteners are attached w/ spot welds

• Rerolled ends are 2-2/3” x 1/2” corrugation

Longer Lengths = Fewer Joints

In Line Fittings: Improved Hydraulics

O RING Gaskets: Soil Tight Joints

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Band Puller: Helps You Get Started

Fabricated Fittings

• Full line of fittings including elbows, tees, wyes, risers, bulkheads, reducers, etc.

Conclusions

• Handle it Properly

• The Right Foundation:

– The Key to a Quality Life

• Quality Backfill and Placement:

– Important for all Systems

– Roadway Embankment is Final Objective

• HUGGER Bands

– Applied Properly

– Stab Joints are Coming