| 66 CORRUGATED METAL PIPE AND PIPE ARCHES
Section 66-1 includes general specifications for constructing corrugated metal pipe and pipe arches.
Corrugated metal pipe arches must comply with section 66-1.02E.
Excavation, backfill, and shaped bedding must comply with section 19-3.
Submit a certificate of compliance for:
1. Corrugated steel materials
2. Corrugated aluminum materials
66-1.01D Quality Assurance
Perform field leakage tests on corrugated steel pipe siphons.
Fill the pipe with water to a hydrostatic head of 10 feet above the highest point in the line after the pipe has been laid and backfill has been placed and compacted to a minimum of 2 feet above the pipe.
Conduct a hydrostatic test for a period of not less than 24 hours. Make accurate measurements of the water required to maintain the test pressure during the test period. Any leakage developed by the test must not exceed the allowable leakage as computed by the following formula:
E = 0.00002H1/2LD
E = allowable leakage in gpm
H = difference in elevation in feet between the water surface at 10 feet above the highest point in the line and the invert elevation of the pipe at its lowest point
L = length of the culvert or drainage pipe in feet
D = internal diameter of the pipe in inches
Furnish all water, materials, and labor for the hydrostatic test. Conduct all hydrostatic tests in the presence of the Engineer. The Department does not pay for hydrostatic testing.
Stop any leakage in excess of the allowable leakage as authorized. Repeat the hydrostatic test until the total leakage does not exceed the allowable leakage. Stop all obvious leaks whether or not the leakage from the line exceeds the allowable leakage.
Corrugated metal pipe must be corrugated aluminum pipe or corrugated steel pipe as described. Do not mix aluminum and steel materials in any installation, except coupling band fastening hardware.
Ship, handle, and lay corrugated metal materials in a way that prevents bruising, scaling, or breaking of the galvanized surface, aluminized surface, or protective coating.
If concrete collars or tee connections are required, construct the collars or tee connections with minor concrete. Reinforcement must comply with section 52.
66-1.02B Dimensions and Thickness
Dimensions and thicknesses shown are nominal and must comply with AASHTO M 36 for corrugated steel pipe and AASHTO M 196 for corrugated aluminum pipe.
The nominal sheet thickness for corrugated metal pipe must be equal to or greater than the nominal thickness described.
Lapped longitudinal seams of riveted pipe arches must be placed in the top arch and must be staggered so as to alternate on each side of the center of the top arch at least 3 inches.
Where coating, lining, or paving is shown, pipes must be protected with bituminous coating or bituminous lining, or have the invert paved with one or more of the following materials:
1. Bituminous coating
2. Polymeric sheet coating
3. Bituminous lining
4. Bituminous invert paving
Remove moisture, dirt, oil, unbonded or incompatible paint, grease, alkalies, or other foreign matter from the surface to be protected before application of the coating. lining, or paving material.
The bituminous coating for bituminous coated pipes must be applied to the inside and outside of pipes to a minimum thickness of 0.05 inch under AASHTO M 190, Type A.
An asphalt mastic coating may be used instead of the bituminous coating on corrugated steel pipe if linings and paving are not required. The asphalt mastic must be placed on the outside surface of the pipe. The inside of the pipe does not need to be coated.
Asphalt mastic coatings must comply with AASHTO M 243, except the asbestos fibers are not required. The asphalt mastic material must be applied uniformly to the surface with a thickness of at least 0.05 inch at any point. The asphalt mastic coating must be applied at the fabrication plant. Pinholes, blisters, cracks, or lack of bond are cause for rejection.
Polymeric sheet coatings must comply with AASHTO M 246. The polymeric sheet coating must be applied to both sides of the galvanized sheet before corrugating. The thickness of the coating must be at least 0.010 inch. Pinholes, blisters, cracks, or lack of bond are cause for rejection.
A bituminous lining must be applied to the inside of the pipe over the bituminous coating wherever bituminous lining is shown.
For bituminous lined corrugated metal pipe, the rivet heads inside the pipe must be located in the valley of the corrugation. Provisions must be made at the ends of the pipes to retain bituminous material during the fabrication process. Both the inside and outside surfaces must be bituminous coated under AASHTO M 190, Type A. In addition to this coating, the valleys on the inside periphery must be filled by the centrifugal process with the same type of bituminous material to the extent that the thickness on the crests of corrugations is at least 1/8 inch. The lining must be smooth and uniform, and its surface must be parallel to a line projected along the crests of the corrugations.
Bituminous paving must be applied to the inside bottom portion of the pipe over the bituminous coating under AASHTO M 190, Type C, where bituminous paving is shown.
If protective coatings are applied to pipes, clearly identify the thickness of the metal on each section of pipe and fittings on the inner surface with paint or by other authorized means.
Repair damaged protective coatings, linings, and invert paving. Use bituminous material under AASHTO M 190 or other authorized materials to repair damaged bituminous coatings. Use asphalt mastic material under AASHTO M 243 to repair damaged asphalt mastic coatings. Use tar base material under AASHTO M 243 to repair damaged polymeric sheet coatings.
Coupling bands and connecting hardware for coated pipes must have a protective coating. Coupling bands to be protected by coatings under AASHTO M 190 may be single-dipped with the coating thickness requirement waived.
66-1.02D Coupling Bands
Coupling bands for corrugated metal pipe must comply with either section 66-1.02D or section 61-2.01D(1)(b).
Choose one of the types of corrugated metal pipe coupling bands shown. The metal bands must be corrugated, dimpled, or otherwise formed in a way that will effectively engage the corrugations of the pipe ends.
Coupling bands for corrugated steel pipe must comply with AASHTO M 36. Coupling bands for corrugated aluminum pipe must comply with AASHTO M 196.
If channel or wing channel coupling bands are used, the interior bend radii of the pipe flange and the channel must be at least the thickness of the metal of which they are formed.
Joints for siphons must consist of connections made with coupling bands shown for positive joints. Do not use universal coupling bands.
Joints for siphons and joints for pipes shown as watertight must be watertight under pressure and all conditions of expansion, contraction, and settlement, and must comply with section 61-1.01D(1)(b) for watertightness.
66-1.02E Corrugated Steel Pipe
Corrugated steel materials must comply with AASHTO M 36 and be fabricated from either zinc-coated steel sheet or aluminum-coated steel sheet as shown.
Zinc-coated steel sheet must comply with AASHTO M 218, except the coating weight is determined under ASTM A123/A123M and A153/A153M.
Aluminum-coated steel sheet must comply with AASHTO M 274.
Corrugated steel pipe must be fabricated by one of the following methods:
2. Helically corrugated steel pipe with a continuous helical lock seam
3. Continuous helical welded seam paralleling the corrugation
Pipes fabricated from 0.050-inch thick sheets must be helically corrugated steel pipe with a continuous helical lock seam or a continuous helical welded seam.
Annular corrugated steel pipe must be fabricated from sheets having either 2-2/3-by-1/2-inch or 3-by-1-inch corrugations.
66-1.02E(2)(b) Fabrication by Riveting
Pipes fabricated by riveting must comply with AASHTO M 36.
66-1.02E(2)(c) Fabrication by Continuous Helical Seam
Helically corrugated steel pipe must comply with AASHTO M 36.
Helically corrugated pipe must be fabricated using corrugation profiles and continuous helical seam pitches as shown in the following table:
aPitch must be measured at right angles to the direction of corrugations. A tolerance of ±1/2 inch on seam pitch is allowable.
66-1.02E(2)(c)(ii) Fabrication by Continuous Lock Seam
You may use pipes fabricated with a continuous helical lock seam extending from end to end of each length for full circle and equivalent pipe arch sizes. Fabrication must comply with AASHTO M 36.
66-1.02E(2)(c)(iii) Fabrication by Continuous Welded Seam
You may use pipes fabricated with a continuous helical welded seam parallel to the corrugations for full circle and equivalent pipe arch sizes. Control the welding process so that the combined width of the weld and adjacent spelter or aluminum coating burned by the welding does not exceed 3 times the metal thickness.
If the spelter is damaged by the welding outside the specified area, repair the weld and damaged spelter adjacent to the weld under section 75-1.02B
If the metalizing is applied immediately in a continuous operation following the resistance welding, apply a coating of aluminum to the welded area of aluminum-coated pipe using the metalizing process under AWS C2.2, except surface cleaning will not be required.
66-1.02E(3) End Finish
Helically corrugated steel pipe ends may be rerolled to form annular corrugations extending at least 2 corrugations from the pipe end or to form an upturned flange with or without reformed annular corrugations. The diameter of the reformed ends must not exceed that of the pipe barrel by more than the depth of the corrugation. All types of pipe ends, whether rerolled or not, must be matched in a joint so that the maximum difference in diameter of the abutting pipe ends is 1/2 inch.
If the ends of helically corrugated steel lock seam pipes have been rerolled, the lock seam in the rerolled end must not contain visible cracks in the base metal and the tensile strength of the lock seam must be at least 60 percent of the tensile strength required for the remainder of the pipe. This requirement does not apply to the lock seam located within a flange formed in rerolling. The rerolled ends of the pipe and flanges must exhibit good workmanship and must not have open lock seams.
If corrugated steel pipe is rerolled for coupling with a wing channel coupling or a channel coupling band, the maximum distance from any point on the end of the pipe to the plane, normal to pipe axis and passing through the outermost portion of the pipe end, must not exceed 1/2 the width of the channel minus the thickness of the pipe metal. The difference between the minimum and maximum flange diameter must not exceed 1/2 inch.
Fabricate pipes so that they can be joined effectively with the described standard coupling bands.
66-1.02E(4) Damaged Galvanizing
Repair damaged galvanized surfaces under section 75-1.02B.
If you burn the galvanized surfaces by welding, thoroughly clean all the surfaces of the welded connections by wire brushing and remove all traces of the welding flux and loose or cracked galvanizing before repair.
66-1.02E(5) Damaged Aluminum Coatings
Repair damaged aluminum coatings under section 75-1.02B.
66-1.02E(6) Corrugated Steel Pipe Siphons
The thickness of siphons must be the described thickness. If coating is required, coated pipes must comply with section 66-1.02C.
Order pipes for siphons in lengths that will keep the number of field connections to a minimum.
If soldering is required, the outside seams of pipe fabricated by riveting, or continuous helical lock seam must be soldered, the solder being sweated into the joints. If the pipe is fabricated by riveting, rivets on the circumferential seams must be spaced at approximately 2-1/2-inch centers with a maximum spacing of 3 inches. If the pipe is fabricated by a continuous helical welded seam, soldering is not required.
66-1.02F Corrugated Aluminum Pipe
Corrugated aluminum materials must comply with AASHTO M 196 and AASHTO M 197.
Corrugated aluminum pipe must be fabricated by riveting or with a continuous helical lock seam paralleling the corrugations. Annular or helically corrugated pipe must be fabricated from sheets having 2-2/3-by-1/2-inch or 3-by-1-inch corrugations.
66-1.02F(2)(b) Fabrication by Riveting
Pipes fabricated by riveting must be lap joint construction with annular corrugations. Fabrication must comply with AASHTO M 196.
For full circle and equivalent pipe arch sizes, you may install pipes fabricated with a continuous helical lock seam extending from end-to-end of each length. Fabrication must comply with AASHTO M 196.
66-1.02F(3) End Finish
Helically corrugated aluminum pipe ends may be rerolled to form annular corrugations extending at least 2 corrugations from the pipe end. The diameter of the reformed ends must not exceed the diameter of the pipe barrel by more than the corrugation depth. All types of pipe ends, whether rerolled or not, must be matched in a joint so that the maximum difference in diameter of the abutting pipe ends is 1/2 inch.
If the ends of helically corrugated aluminum lock seam pipes have been rerolled, the lock seam in the rerolled end must not contain visible cracks in the base metal and the tensile strength of the lock seam must be at least 60 percent of the tensile strength required for the remainder of the pipe. The rerolled pipe ends must exhibit good workmanship and must not have open lock seams.
Pipes must be fabricated so that they can be joined effectively with the described standard coupling bands.
Excavate a pipe trench to the lines and grades established by the Engineer. Grade and prepare the trench bottom to provide a firm and uniform bearing throughout the entire pipe length.
Lay annular corrugated pipe in a trench with:
1. Outside laps of circumferential joints upgrade
2. Longitudinal laps positioned other than in the invert
3. Separate sections spaced not more than 1-1/2 inches apart and then firmly joined together
Lay helical corrugated pipe in a trench with separate sections spaced not more than 1-1/2 inches apart and then firmly jointed together with corrugations in alignment.
Corrugations or projections on the coupler must properly engage the corrugations of the pipe section before bolts are tightened.
Connect new corrugated metal pipe to new or existing drainage facilities as shown.
Wherever pipes are connected to inlet and outlet structures, place the ends of the pipes flush or cut them off flush with the structure face.
The payment quantity for corrugated metal pipe is the length measured along the centerline of the pipe and parallel with the slope line. The payment quantity includes the length of pipe reducers, bends, wyes, tees, and other branches to the point of intersection. Pipe reducers are paid for as pipe of the larger diameter connected to the reducer.
If pipes are cut to fit a structure or slope, the payment quantity is the length of pipe necessary to be placed before cutting, measured in 2-foot increments.
66-2 SLOTTED CORRUGATED STEEL PIPE
Section 66-2 includes specifications for constructing slotted corrugated steel pipe.
Slotted corrugated steel pipe must be grate-slot type as shown.
Grate assemblies for slotted corrugated steel pipe must comply with section 75-1, but may be fabricated from any of the materials under section 75-1.02 for steel bars, plates and shapes. Any damage to the galvanized surface of the pipe at the toe of the grate assembly fillet weld connection to the pipe must be repaired under section 75-1.02B.
Where a heel guard is shown, the heel guard must be expanded metal and must comply with ASTM F1267, Type II, Class 2, and Grade B. Galvanizing must comply with section 75-1.02B.
Coupling bands for slotted corrugated steel pipe must be galvanized or coated as shown.
Joints must be watertight.
If you use a channel coupling band, place a 3/8-inch-thick closed-cell sponge neoprene gasket or butyl rubber joint sealant in the channel interior for its full width.
If you use a modified hugger band, place a butyl rubber joint sealant between the coupling band and the periphery of the pipe. The butyl rubber joint sealant material must:
1. Be an extruded strip or bead compounded from a nondrying, nontoxic, synthetic resin base with butyl rubber and inorganic extenders and be 100 percent solid material with no shrinkage
2. Be furnished in 5/8-by-1-inch strips or 1-inch-diameter beads on 1-inch-wide release paper and wound into rolls
3. Have enough adhesion so that the strip or bead will adhere to the galvanized steel and be soft enough to allow cold flow if compressed during connection of the pipe sections
4. Not flow or sag at temperatures up to 180 degrees F or become brittle, crack, or lose adhesion at -30 degrees F
5. Contain no migrating components that could leach out or produce a chemical reaction with the galvanized steel
You may use an alternative joint sealant or sealing method for slotted corrugated steel pipe to provide a watertight joint if authorized.
Do not start installation of slotted corrugated steel pipe until after paving of the traffic lanes adjacent to the pipe have been completed at the locations where the pipe is to be placed.
Join slotted corrugated steel pipe with coupling bands as shown.
Cover pipe slots with a heavy duty tape or other authorized covering during backfilling and paving activities to prevent material from entering the slots.
Place cement treated structure backfill for slotted corrugated steel pipe under the details shown and section 19-3.02E(3) for soil cement beddings. Cover the completed cement treated structure backfill with a curing seal of asphaltic emulsion, Grade SS1 or CSS1.
Do not place loads on the cement treated structure backfill within 16 hours after placement.
66-3 SPIRAL RIB PIPE
Section 66-3 includes specifications for constructing spiral rib pipe.
The specifications for profile and fabrication in section 66-1 do not apply to spiral rib pipe.
Steel spiral rib pipe must be fabricated by continuous helical lock seam under section 66-1.02E(2)(c)(ii).
Aluminum spiral rib pipe must be fabricated by continuous helical lock seam under section 66-1.02F(2)(c).
The fabricated rib configuration for spiral rib pipe must be one of the following:
1. Three rectangular ribs spaced midway between seams with ribs 3/4 inch wide by 3/4 inch high at a maximum rib pitch of 7-1/2 inches
2. Two rectangular ribs and 1 half-circle rib equally spaced between seams with ribs 3/4 inch wide by 1 inch high at a maximum rib pitch of 11-1/2 inches with the half-circle rib diameter spaced midway between the rectangular ribs
3. For steel spiral rib pipes, 2 rectangular ribs equally spaced between seams with ribs 3/4 inch wide by 1 inch high at a maximum rib pitch of 8-1/2 inches
The rib pitch measured at right angles to the direction of the ribs may vary by ±1/2 inch.
Coupling bands for spiral rib pipes must comply with section 66-1.02D.
You may use the coupling band shown, or an authorized coupling band under section 61-1.01D(1)(b) for use on a pipe corrugation of 2-2/3 by 1/2 inch for corrugated metal pipe on spiral rib pipe having 2-2/3-by-1/2-inch rerolled annular ends.
66-4 COMPOSITE STEEL SPIRAL RIB PIPE WITH SMOOTH INTERIOR
Section 66-4 includes specifications for constructing composite steel spiral rib pipe with smooth interior.
Composite steel spiral rib pipe must have a smooth interior and must comply with the specifications for corrugated metal pipe in section 66-1 except profile and fabrication.
The precoated exterior of composite steel spiral rib pipe with polymeric sheet coating must comply with section 66-1.02C. The pipe interior must be lined with polyethylene (polyolefin plastomer). The pipe dimensions, wall thickness, and fitting tolerances must comply with ASTM A978/A978M.
Composite steel spiral rib pipe must be fabricated by continuous helical lock seam under section 66-1.02E(2)(c)(ii). Three rectangular ribs must be spaced midway between seams with ribs 3/4 inch wide by 3/4 inch high at a maximum rib pitch of 7-1/2 inches on center. The rib pitch measured at right angles to the direction of the ribs may vary by ±1/2 inch.
Pipes formed from polymer precoated sheets must comply with ASTM A742/A742M, Grade 10, except the sheet side for the pipe interior must have additives that will enhance the bond of the sheet to the extruded polyethylene liner. Before application of protective coatings, the galvanized sheet must be cleaned with an alkaline cleaner followed by chrome pretreatment.
Steel sheets coated with zinc metallic coating must comply with ASTM A929/A929M.
The polyethylene for filling the ribs and the internal liner must be virgin resin. The virgin resin quality characteristics must comply with the values in the following table:
I2+ 7.5g/10 min ± 1.5
Flow rate ratio
0.902 g/cc ± 0.002
45 ± 5
Ash content (%)
Joint coupling bands fabricated from the steel sheets used to manufacture pipes must comply with section 66-1.02C and section 66-1.02D, except steel sheets with polymetric coating on both sides. Coupling bands must be 12 inches wide for nominal pipe diameters less than 60 inches. Coupling bands must be 24 inches wide for nominal pipe diameters 60 inches and greater.
Galvanized nuts, bolts, and washers must comply with sections 75-2 and 75-1.02B.
Expanded rubber gaskets must comply with ASTM D1056, Type 2, Class C, and Grade 1. Protect gaskets from excessive exposure to heat, direct sunlight, ozone, oil, or grease. Gaskets placed over spiral ribs must have a groove routed to match the rib's depth and width before installation. Do not substitute O-rings for gaskets.
The gasket adhesive must be 1 part urethane elastomeric joint sealant under ASTM C920, Type S, Grade NS, Class 25, Use NT, A, and M. Use the sealant within 9 months from the date of manufacture. Store the adhesive at an ambient temperature of 80 degrees F or below. Do not use any adhesive that has been stored at temperatures exceeding 80 degrees F.
Manufactured pipe joints must comply with section 61-2.01D(1)(b) for sleeve joints.
Each standard and random length of pipe must be marked clearly in permanent letters not less than 1/4 inch in height at intervals of 5 feet or less with at least the following:
1. Manufacturer’s code and name or trademark
2. ASTM A978/A978M
3. Nominal pipe size
Each coupling band must be marked clearly with at least the following:
1. Manufacturer’s code and name or trademark
2. ASTM A978/A978M
3. Nominal size
The manufacturer’s code must include the day, month, year, shift, and manufacturing plant.
Store pipes in unit packages with the pipe ends protected from deformation and damage. Support unit packages with racks or dunnage to prevent damage and bending. Stack unit packages to ensure that the weight of the upper units will not cause deformation to pipes in the lower units. Do not store pipes adjacent to electrical or exhaust heat sources.
Do not expose pipes to direct sunlight for periods exceeding 30 days. Cover pipes with an opaque sheeting material to provide sun protection. Arrange the opaque sheeting material so that it provides adequate air circulation around pipes to reduce excessive heat accumulation. Ship gaskets in containers that will prevent damage from UV exposure and handling. Do not store gaskets near electrical or exhaust heat sources or where they will be exposed to the sunlight for more than 48 hours.
Lay composite steel spiral rib pipe in the same way specified for helical corrugated pipe in section 66-1.03, except the gap between pipe sections must not be more than 1/2 inch. Clean the pipe ends before applying the adhesive and installing the gaskets and the coupling bands.
Cover the ends of installed composite steel spiral rib pipe that were not backfilled after installation at the end of each day.
Repair damaged polymeric pipe coatings on pipe and pipe fittings. For polymeric coatings with damaged areas less than 36 square inches in area, repair breaks and scuffs under the manufacturer's recommended repair procedures. Do not install a pipe if the individual breaks or total area of the breaks exceeds 36 square inches in area or if the total area of the breaks exceeds 0.5 percent of the total pipe surface area.
The polymer repair material must be one of the following:
1. Denflex Coating - Dennis Chemical Company, St. Louis, MO
2. Scotch-Clad 1706 Protective Coating - 3M Company, St. Paul, MN
3. Ranbar Trispec TPC-515-7 Black Synthetic Coating - P.D. George Company, Manor, PA
Clean and dry surfaces to be coated. The repair coating must be at least 0.010 inches thick after hardening and must bond securely and permanently to the pipe. Apply 6 coats if the thickness of the repair coating is not measured. Allow 30 minutes drying time between the coats.