96M03/29/06

S557-96M.doc

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  Use on projects as appropriate.

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**Section 557. - TIMBER STRUCTURES**

**Material**

**557.02.** [Add the following:]{.underline}

> Structural glued laminated timber

**Construction Requirements**

**557.03. General.** [Add the following:]{.underline}

Store and protect glued laminated timber according to the
recommendations for Unloading and Handling, Job Site Storage, and
Erection in "Recommended Practice for Protection of Structural Glued
Laminated Timber During Transit, Storage, and Erection." AITC 111.

Use slings or other devices to protect corners of heavy construction
timbers and banded packages of lighter construction timber.

Cut and form all lumber and construction timber so all joints will have
even bearing over the entire contact surface. Do not use shims in making
joints. Construct all joints to be closed. Drive nails and spikes to set
the heads flush with the wood surface.

Use the same end, face, and edge of the timber member for all layout
dimensions. Bore all holes from mating faces.

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  Include the following when treated timber is used:

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**557.04 Treated Timber.** [Delete the second paragraph and substitute
the following:]{.underline}

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  See the commentary attached to standard SCR 716.03 for discussion of
  preservative type selection.

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Carefully trim all field cuts or abrasions made in fabricated timber
after treatment and then dip, soak, spray or apply three brush coats of
a copper napthenate solution prepared in accordance with AWPA M4. Apply
the preservative in such a manner that it does not drip or spill into
the aquatic environment or onto the soil.

**557.06 Holes for Bolts, Dowel, Rods, and Lag Screws.** [Delete the
text and substitute the following:]{.underline}

Bore all holes before preservative treating the wood. Bore holes for
round drift pins and dowels to the same diameter as the dowel or pin.
Bore holes for square drift pins and dowels to a diameter equal to the
side dimension of the pin or dowel.

Bore holes for galvanized bolts to 3 millimeter larger than the diameter
of the bolt.

Bore holes for lag screws according to Subsection 7.3.1 of the American
Institute of Timber

Construction *Timber Construction Manual.*

**557.07 Bolts and Washers.** [Delete the text and substitute the
following:]{.underline}

Unless indicated otherwise on the contract drawings, all hardware for
timber structures shall be galvanized, except for glued laminated deck
panel dowels. All fasteners, including nails, spikes, bolts, washers,
and timber connectors, other than malleable iron or cast-iron shall be
galvanized.

Use washers under all bolt head or nuts in contact with wood. Use
malleable iron washer with a diameter approximately three times the bolt
diameter. Use cast-iron washers when the timber is in contact with the
ground. Use square washers only when indicated on the contract plans.

Cut off excess bolt lengths of more than 25-millimeters. After final
tightening, check or burr all bolts with a pointing tool to prevent
loosening of the nuts.

**557.20 Acceptance.** [Add the following:]{.underline}

Preservative treatment will be evaluated under Subsections 106.02 and
106.03.