96E03/29/06

S602-96E.doc

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  Include section 602 when grout or concrete backfill is specified.

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**Section 602. - CULVERTS AND DRAINS**

**Material**

**602.02** [Delete reference to "Special grout backfill, 704.11" and
substitute the following:]{.underline}

> Lean concrete backfill 614

[Add the following:]{.underline}

> Precast Concrete Units 725.11

**Construction Requirements**

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  Use when culvert pipe is required.

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**602.03 General.** [Delete the text and substitute the
following:]{.underline}

Furnish culvert pipe with a wall thickness not less than that shown on
the plans or determined from the fill-height tables included in the
plans. Use the same material and coating on all contiguous pipe sections
and special sections, such as elbows and branch connections. For culvert
extensions, furnish the same material as the existing culvert.

The plans show the approximate size, location and length of culverts.
Determine final size, location, skew, length, elevations, and grade
according to Subsection 152.03(g). Do not order culvert material until
the CO has accepted the final structure size, length, and alignment.

Perform excavation and backfill work under Section 209.

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  Use when metal pipe is required or permitted.

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[Add the following:]{.underline}

Do not use precast units unless included in the plans or approved by the
CO.

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  Use when metal pipe is required or permitted.

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**602.05 Laying Metal Pipe.** [Delete the second paragraph and
substitute the following:]{.underline}

Join pipe sections together with soil tight bell and spigot joints or
coupling bands according to AASHTO M 36 or M 196. Limit the use of bell
and spigot joints to slopes of 10 percent or less and limit the use of
coupling bands with projections (dimples) to attaching prefabricated
flared end sections.

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  Use when plastic pipe is required or permitted.

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**602.06 Laying Plastic Pipe.** [Add the following:]{.underline}

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| Insert if a reason is needed:                                         |
|                                                                       |
| {REASON: The standard split coupler used for plastic pipe is a "soil  |
| tight" connection which actually permits a fair amount of finer       |
| material to move through the joint. ADS has a \"silt tight\"          |
| connection which is superior to the soil tight, but we don\'t know if |
| Hancor has an equivalent; besides, a silt tight connection still      |
| allows for water leakage. The water tight joint is the superior joint |
| and is CFLHD\'s preference until we become comfortable with a lesser  |
| joint. Plastic end sections are too flimsy and collapse unless they   |
| are reinforced or stiffened. Shari Brandt distributed this CFLHD      |
| Division SS for 602.07 to the SCG on 1/27/00. On 9/13/00, the SCG     |
| approved this proposals based on the comments received.}              |
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Provide watertight joints for plastic pipe culverts.

Provide soil-tight bell and spigot joints for plastic pipe culverts.

If plastic end sections are used, reinforce and stiffen them such that
inward buckling during construction is less than ½ inch with 2000 lb of
force.