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duits and outside circumferential laps of flexible conduits shall be placed facing upstream. Flexible conduit shall be placed with longitudinal laps or seams at the sides.

Paved or partially lined conduit shall be laid so that the longitudinal center line of the paved segment coincides with the flow line. Elliptical and eliptically reinforced conduits shall be placed with the major axis within 5 degrees of a vertical plane through the longitudinal axis of the conduit.

603.06 Joining Conduit. Rigid conduits may be of bell and spigot or tongue and groove design unless one type is specified. The method of joining conduit sections shall be such that the ends are fully entered and the inner surfaces are reasonably flush and even.

Joints shall be made with (a) portland cement mortar, (b) portland cement grout, (c) rubber gaskets, (d) oakum and mortar, (e) oakum and joint compound (f) plastic sealing compound, or by a combination of these types, or any one type, as may be specified.

Mortar joints shall be made with an excess of mortar to form a continuous bead around the outside of the conduit and finished smooth on the inside. For grouted joints, molds or runners shall be used to retain the poured grout. Rubber ring gaskets shall be installed so as to form a flexible watertight seal. Where oakum is used the joint shall be calked with this material and then sealed with the specified material.

When portland cement mixtures are used, the completed joints shall be protected against rapid drying by suitable covering material.

Flexible conduits shall be firmly joined by coupling bands.

Conduit shall be inspected before any backfill is placed. Any pipe found to be out of alignment, unduly settled, or damaged shall be taken up and relaid or replaced.

603.07 Field Strutting. Where required by the plans, the vertical diameter of round flexible conduit shall be increased 5 per cent by shop elongation or by means of jacks applied after the entire line of conduit has been installed on the bedding but before backfilling. The vertical elongation shall be maintained by means of sills and struts or by horizontal ties when so specified. Only horizontal ties shall be used on paved invert pipe.

Ties and struts shall be left in place until the embankment is completed and compacted, unless otherwise shown on the plans.

These construction specifications shall equally apply in the case of relaid conduits. In addition, all conduit salvaged for relaying shall be cleaned of all foreign material prior to reinstallation.

603.08 Backfilling. Materials for backfill on each side of the conduit for the full trench width and to an elevation of 1 foot above the top of the conduit, shall be fine, readily compactible soil or granular material selected from excavation or from a source of the contractor's choice, and shall not contain frozen lumps, stones that would be retained on a 2-inch ring, chunks of highly plastic clay, or other objectionable material. Granular backfill material shall have not less than 95 percent passing a 12-inch sieve and not less than 95 percent retained on a No. 4 sieve. Oversized material, if present, shall be removed at the source of the material, except as directed by the Engineer.

When the top of the conduit is even with or below the top of the trench, backfill material shall be placed at or near optimum moisture content and compacted in layers not exceeding 6 inches (compacted) on both sides and to an elevation 1 foot above the top of the conduit. Care shall be exercised to thoroughly compact the backfill under the haunches of the conduit. The backfill shall be brought up evenly on both sides of the conduit for the full required length. Except where negative projecting embankment-type installation is specified, the backfill material shall be placed and compacted for the full depth of the trench.

When the top of the conduit is above the top of the trench, backfill shall be placed at or near optimum moisture content and compacted in layers not exceeding 6 inches (compacted) and shall be brought up evenly on both sides of the conduit for its full length to an elevation 1 foot above the top of the conduit. The width of backfill on each side of the conduit for the portion above the top of the trench shall be equal to twice the diameter of the conduit or 12 feet, whichever is less. The backfill material used in the trench section and the portion above the top of the trench for a distance on each side of the conduit equal to the horizontal inside diameter and to 1 foot above the top of the conduit shall conform to the requirements for backfill material in the first paragraph of this subsection. The remainder of the backfill shall consist of material from excavation and borrow that is suitable for embankment construction.

Compaction to the density specified in subsection 203.10 shall be achieved by use of mechanical tampers or by rolling.

All conduit after being bedded and backfilled as specified in this section shall be protected by a 4-foot cover of fill before heavy equipment is permitted to cross during construction of the roadway.

603.09 Imperfect Trench. Under this method, for rigid conduit, the embankment shall be completed as described above, to a height above the conduit equal to the vertical outside diameter of the conduit plus one foot. A trench equal in

width to the outside horizontal diameter of the conduit and to the length shown on the plans or directed shall then be excavated to within one foot of the top of the conduit, trench walls being as nearly vertical as possible. This trench shall be loosely filled with highly compressible soil. Straw, hay, corn stalks, leaves, brush, or sawdust may be used to fill the lower 14 to 13 of the trench. Construction of embankment above shall then proceed in a normal manner.

In no case shall the imperfect trench extend for the full length of the conduit.

Method of Measurement

603.10 Conduit of the different types and sizes, both new and relaid, will be measured by the linear foot in place. Conduit with sloped or skewed ends will be measured along the invert.

End sections will be measured by the number of units installed.

Branch connections and elbows will be included in the length measurement for conduit, or they may be measured by the number of units installed.

Class B bedding material placed and approved will be measured by cubic yards in the delivery vehicles or, whenever practicable, will be measured in place.

When the bid schedule contains an estimated quantity for "Furnishing and Placing Backfill Material, Pipe Culverts," the quantity to be paid for will be the number of cubic yards complete in place and accepted, measured in final position between limits as follows:

(1) Measurement will include backfill material in the trench up to the top of the original ground line but will not include any material placed outside of vertical planes 18 inches up outside of and parallel to the inside wall of the pipe at its widest horizontal dimension.

(2) When the original ground line is less than one foot above the top of the pipe, the measurement will also include the placing of all backfill material above the original ground line adjacent to the pipe for a height of one foot above top of pipe and for a distance each side of the pipe not greater than the widest horizontal dimension of the pipe.

(3) The measurement will include the placing of backfill material in all trenches of the imperfect trench method. Material re-excavated for imperfect trench construction will be measured for payment under section 206.

Basis of Payment

603.11 The accepted quantities of conduit, determined as provided above, will be paid for at the contract unit price per linear foot for conduit of the types and sizes specified complete in place. End sections and, when so specified, branch connections and elbows, will be paid for at the contract unit price per each for the kind and size specified complete in place.

Excavation for culverts and storm drains, including excavation below flow line grade and for imperfect trench, will be measured and paid for as provided in Section 206Structure Excavation

Concrete for Class A bedding will be paid for under section 601.

When the bid schedule does not contain an estimated quantity for “Furnishing and Placing backfill material, pipe culvets,” payment for placing backfill material around pipe culverts will be considered as included in the payment for the excavation of the backfill material.

Payment will be made under:

Pay item

Pay unit

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inch cast iron pipe, class-
inch corrugated steel pipe,-
Gage
inch span,-inch rise corru-
gated steel pipe arch,—Gage
inch corrugated steel end sec-
tion,-Gage
inch span,-inch rise corru-
gated steel end section,-Gage
inch bituminous coated corru-
gated steel pipe,–Gage,
type


inch bituminous coated paved
invert corrugated steel pipe,-
Gage, type-
inch span,-inch rise bitumin-

coated corrugated steel
pipe arch,—Gage, type-
inch bituminous coated corru-
gated steel end section,
Gage
inch span,-inch rise, bitumi-
nous coated corrugated steel
end section,-Gage

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Pay item
603 (11) inch asbestos bonded bitumi-

nous coated corrugated steel

pipe,-Gage 603 (12) inch asbestos bonded bitumi

nous coated paved invert cor

rugated steel pipe,-Gage
603 (13) inch span,-inch rise asbestos

bonded bituminous coated cor-
rugated steel pipe arch,-

Gage
603 (14) inch asbestos bonded bitumi-

nous coated corrugated steel

end section,-Gage
603 (15) inch span,-inch rise asbestos

bonded bituminous coated cor-
rugated steel

end

section, -Gage 603 (16) inch corrugated aluminum pipe,

Gage 603 (17) inch paved invert corrugated

aluminum pipe,–Gage 603 (18) inch span,-inch rise, corru

gated aluminum pipe arch,

-Gage 603 (19) inch corrugated aluminum end

section,-Gage 603 (20) inch span,-inch rise corru

gated aluminum end section,

Gage 603 (21) inch reinforced concrete pipe,

class— 603 (22) inch reinforced concrete end

section 603 (23) inch nonreinforced concrete

pipe, class— 603 (24) inch vitrified clay lined rein

forced concrete pipe, class— 603 (25) inch vitrified clay pipe 603(26) inch asbestos cement pipe 603 (27) Pipe Elbow603(28) Branch connection603 (29) Pipe bedding material, class 603 (30) Furnishing and placing backfill

material, pipe culverts

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Cubic yard.

Cubic yard.

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