pipe construction ohio department of transportation corrugated metal pipe installation brian flint...
TRANSCRIPT
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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H C
onstru
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roducts, In
c. 80 years of M
etal Produ
ct Inn
ovation
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
D
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
HU
GG
ER
Ba n
d
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