**Construction Specification 751---Corrugated Metal Pipe**

**1. Scope**

The work consists of furnishing and placing circular, arched, or
elliptical corrugated metal pipe and the necessary fittings.

**2. Material**

Pipe and fittings shall conform to the requirements of Section 850,
Roadway Pipe, of the latest edition of the Alabama Department of
Transportation Standard Specifications for Highway Construction.

**3. Coupling bands and hardware**

Pipe joint coupling bands shall be provided meeting the requirements
specified in section 9 of this specification.

Hardware consisting of coupling bands and band fastening devices, such
as connecting bolts, rods, lugs, and angles used in conjunction with
zinc-coated iron or steel pipe, shall be galvanized by the hot-dip
method. Hardware used in conjunction with aluminum pipe and aluminum or
aluminum-zinc alloy-coated iron and steel pipe shall be of the same
material as the pipe except that hot-dip galvanized or cadmium-plated
fasteners may be used. The surface of all band-fastening devices for
pipe specified with bituminous or polymer coating shall be coated with
asphalt-mastic material meeting the requirements of ASTM A 849. The
coupling band shall be coated similar to that specified for the pipe
unless otherwise specified in section 9 of this specification.

Coupling bands shall be installed to provide straight alignment of the
connecting pipe ends. Unless otherwise specified in section 9 of this
specification, the bandwidth shall be as specified in ASTM A 760 and A
762. The bands shall be positioned to overlap adjacent pipe ends
equally. The coupling bands shall be corrugated to match the
corrugations of the pipe section ends being connected.

**4. Fabrication**

Fabrication of appurtenant sections shall be performed as shown on the
drawings and described in section 9 of this specification. The items may
consist of inlet sections, outlet sections, end sections, elbows, skew
or beveled sections, rod reinforced ends, cut-off collars, or headwalls.
Fabrication of these appurtenant sections shall be made from
metallic-coated material identical to that from which the attached pipe
is fabricated. Fabrication shall be of a quality and finished
workmanship equal to that required for the pipe.

**5. Handling the pipe**

The contractor shall furnish equipment as necessary to install the pipe
without damaging the pipe or coating. The pipe shall be transported and
handled in a manner to prevent damage to the pipe and coating.

**6. Laying and bedding the pipe**

Unless otherwise specified, the pipe shall be installed in accordance
with the manufacturer\'s recommendations. Pipe shall be installed so no
reversal of grade between joints results unless otherwise shown on the
drawings. The pipe shall be installed with the outside laps of
circumferential joints pointing upstream and with longitudinal laps at
the sides near the vertical mid-height of the pipe.

Field welding of corrugated galvanized iron or steel pipe is not
permitted. The pipe sections shall be joined with fabricator-supplied
coupling bands meeting the specified joint requirements. The coupling
shall be installed as recommended by the fabricator.

The pipe shall be firmly and uniformly bedded throughout its full length
to the depth and in the manner specified on the drawings.

Perforated pipe shall be installed with the perforations down and
oriented symmetrically about a vertical centerline. Perforations shall
be clear of any obstructions at the time the pipe is installed in its
final position.

The pipe shall be loaded sufficiently during backfilling to prevent
displacement from line and grade and to maintain full contact with the
bedding during the placement operations.

**7. Repair of damaged coating**

Any damage to the metallic coating shall be repaired by cleaning the
damaged surface area by sand blasting, power disk sanding, or wire
brushing. All loose and cracked coating, dirt, and any products of
corrosion shall be removed before application of paint. Oil and grease
material shall be removed by use of a solvent. The surface shall be
clean and dry during the painting period and until the coating has
completely dried.

Painting shall be accomplished by one of the following options based
upon installed exposure conditions of the pipe as determined by the
engineer.

Normal exterior or interior atmospheric exposure:

a\. Zinc dust - zinc oxide primer, ASTM D 79 and D 520

b\. Single package, moisture cured urethane prime in silver metallic
color, or

c\. Zinc-rich cold galvanized compound, brush, or aerosol application

Submergence in water exposure:

a\. Zinc dust - zinc oxide primer, ASTM D 79 and D 520

b\. Zinc dust paint, ASTM D 4146

When the metallic coating is damaged in any individual area larger than
12 square inches or if more than 0.2 percent of the total surface area
of a single pipe section is damaged, that section of pipe will be
rejected.

Breaks or scuffs in bituminous coatings that are less than 36 square
inches in area shall be repaired by applying two coats of hot-asphaltic
paint or a coating of cold-applied bituminous mastic. The repair coating
shall be a minimum of 0.05 inch thick after hardening and shall bond
securely and permanently to the pipe and coating. The material shall
meet the minimum physical requirements for bituminous coating in ASTM A
849 and A 885. Whenever individual breaks exceed 36 square inches in
area or when the total area of breaks exceeds 0.5 percent of the total
surface area of an individual pipe section, that section of pipe will be
rejected.

Bituminous coating damaged by welding of coated pipe or pipefittings
shall be repaired as specified in this section for breaks or scuffs in
bituminous coatings.

Breaks or scuffs in polymer coatings that are less than 36 square inches
in area shall be repaired by the application of a polymer material
similar to and compatible with the durability, adhesion, and appearance
of the original polymer coating, as described in ASTM A 849, paragraph
6.8. The repair coating shall be a minimum thickness of 0.010 inch (10
mils) after drying. Whenever individual breaks exceed 36 square inches
in area or when the total area of breaks exceeds 0.5 percent of the
total surface area of the individual pipe section, that section of pipe
will be rejected.

**8. Measurement and payment**

***Method 1---***For items of work for which specific unit prices are
established in the contract, the quantity of each type, class, size, and
gauge of pipe is determined to the nearest 0.1 foot by measurement of
the laid length of the pipe along the centerline of the pipe. Payment
for each type, class, size, and gauge of pipe is made at the contract
unit price for that type, class, size and gauge of pipe. Such payment
constitutes full compensation for furnishing, transporting, and
installing the pipe and fittings and all other items necessary and
incidental to the completion of the work except items designated as
*special fittings*. Special fittings are those sections of pipe
requiring special fabrication to meet layout requirements. Payment for
special fittings is made at the contract unit price for special fittings
(CMP).

***Method 2---***For items of work for which specific unit prices are
established in the contract, the quantity of each type, class, size, and
gauge of pipe is determined as the sum of the nominal laying lengths of
the pipe sections installed. Payment for each type, class, size, and
gauge of pipe is made at the contract unit price for that type, class,
size, and gauge of pipe. Such payment constitutes full compensation for
furnishing, transporting, and installing the pipe and fittings and all
other items necessary and incidental to the completion of the work
except items designated as *special fittings*. Special fittings are
those sections of pipe requiring special fabrication to meet layout
requirements. Payment for special fittings is made at the contract unit
price for special fittings (CMP).

***Method 3---***For items of work for which specific lump sum prices
are established in the contract, payment for corrugated metal pipe
structures is made at the contract lump sum price. Such payment
constitutes full compensation for furnishing, fabricating, transporting,
and installing the pipe structure complete with metal pipe, fittings,
and appurtenances, and all other items necessary and incidental to
completion of the work, which includes, except as otherwise specified,
required excavation, dewatering, and earth backfill.

***All Methods---***The following provisions apply to all methods of
measurement and payment. Compensation for any item of work described in
the contract, but not listed in the bid schedule, is included in the
payment for the item of work to which it is made subsidiary. Such items
and items to which they are made subsidiary are identified in section 9
of this specification.

**9. Items of work and construction details**

The 18 in. diameter corrugated metal outlet pipes shall be fabricated
from 12 gage metal with polymer coating applied to both the interior and
exterior surfaces. Coating shall be polymer grade, 10/10 as specified in
ASTM A 762. The pipe shall be fabricated from steel sheets with
corrugations 2 2/3 in. x 1/2 in. and the sheets connected with folded
lock seams. The connecting bands shall be fabricated from 16 gage metal
and shall be coated with the same material as the pipe sections. The
pipes shall be connected with Type 10-C bands (24 in. wide min.) with
four 1/2 in. diameter rods and lugs. All rods and nuts will be
retightened 24ÿhours after initial tightening. Rods and nuts shall be so
threaded and shall be of sufficient length to develop full rod strength
without stripping threads.

Joints shall be sealed with strips or bands of preformed mastic sealing
compound (Ram Neck or Equivalent). Sealing compound shall be placed in
the reformed corrugations and across the lap area of the band as shown
on the drawings and/or in accordance with the manufacturer\'s
recommendations. All joints shall be wrapped and totally encased with
geotextile prior to backfill as shown on the drawings. The backfill
around the pipes shall not contain any rocks, hard clods or clumps of
soil and/or woody materials that could damage the geotextile or the
walls of the pipe. Items of work to be performed in conformance with
this specification and the construction details therefore are:

[Bid Item 18, Pipe, Corrugated Metal, 18 in. Diameter, Smooth
Lined]{.underline}

(1) This item shall consist of furnishing and installing the 18 in.
    diameter corrugated metal outlet pipes, connecting bands and the 4
    ft. + stubout the site as shown on the drawings.

(2) The 18 in. diameter corrugated steel pipe shall conform to the
    requirements of Material Specification 551 and ASTM A762. The pipe
    shall be Type IA, round and helically corrugated with a corrugated
    outer shell and smooth metal liner .

(3) The outlet pipes shall be furnished in 40 ft. minimum lengths with
    shorter sections only as required to fit design lengths.

(4) A minimum of two lifting tabs will be fabricated at equal distances
    along each pipe section for unloading and installing the pipe.

(5) Measurement and payment shall be by Method