96sps_557.doc

SPECIAL PROJECT SPECIFICATION

LITTLE SALMON PACK BRIDGE

Section 557 – TIMBER STRUCTURES

557.01 Work.

This work shall consist of assembly and installation of the treated wood structure provided on site by the Forest service.

No log forks or any device that penetrates into the treated lumber members will be allowed for placement of the structure. The treated lumber shall not be dragged on the ground or have cables in direct contact with wood members.

A cordless drill will be allowed for the pre-drilling of holes for bridge assembly.

557.03 General.

Open-stack untreated material to shed water. Stack material in layers on spacers (stickers) that extend across the full width of the stack to allow for free air circulation.

Align all stickers vertically and space them at regular intervals.

Close-stack treated material to shed water.

Protect material from the water. If covered, use sheet material such as water-resistant paper or opaque polyethylene film. Do not cover with impervious membranes, such as polyethylene film, during dry weather. Slit individual wrappings full length or puncture on the lower side to permit drainage of water.

Store and protect glued-laminated timber in accordance with the recommendations for Loading and Handling, Job Site Storage, and Erection in “Recommended Practice for Protection of Structural Glued-Laminated Timber During Transit, Storage, and Erection,” published by the American Institute of Timber Construction, AITC 111.

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

557.04 TREATED TIMBER. Handle treated timber according to the Consumer Information Sheet published by AWPA. Do not cut, frame, or bore treated timber after treatment unless approved by the CO. Handle treated timbers carefully and do not drop, damage outer fibers, or penetrate the surface with tools. Do not use cant dogs, hooks or pike poles.

Field treat all cuts, abrasions, bolt holes, and recesses that occur after treatment in accordance with the requirements specified in AWPA standard M4, Standard for the Care of Pressure-Treated Wood Products. Plug all unused holes with preservative-treated plugs. Perform all field-applied preservation treatment with necessary precautions so as to prevent and soil and/or water contamination.

557.06 Workmanship. Cut and form all lumber and construction timbers 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.

557.07 Holes for Bolts and Lag Screws. Bore holes for machine bolts with a bit 1/16” larger than the bolt diameter, except when galvanized bolts are specified. In this case, drill all holes 1/8” greater than the bolt diameter.

Prebore lag bolt holes using two diameters, one for the shank and one for the threads.

The lead hole for the shank is to be 1/16” larger than the shank diameter and is to be bored to a depth of penetration of the shank. The lead hole for the threaded portion is to be 70% of the bolt diameter shown on the PLANS and is to be bored at least to the length of the threads. DO NOT DRIVE LAG BOLTS WITH A HAMMER.

557.08 Hardware. All hardware is furnished on the site by the Government as SHOWN ON THE DRAWINGS. Work shall conform to the specified below.

(a) Bolts and washers. Final tighten all nuts to provide proper bearing, and cut off excess bolt length of more than ½”. After final tightening, check or burr all bolts effectively with a pointing tool to prevent loosening of the nuts.

Use malleable iron washers with a diameter approximately four times the bolt diameter under all bolt heads or nuts in contact with wood , unless otherwise SHOWN ON THE DRAWINGS.

557.17 Stringers. Glued-laminated stringers shall be positioned so that the camber is

up. Diaphragms between stringers shall be neatly and accurately framed and securely fastened.

Follow erection procedures given in FPL-263, Forest Service, Forest Products

Laboratory (FPL), Madison, Wisconsin.

Measurement

557.24 Method.

Use the method of measurement that is DESIGNATED IN THE SCHEDULE OF ITEMS.

557.25 Basis. The accepted quantities will be paid for at the contract unit price for each PAY ITEM DESIGNATED IN THE SCHEDULE OF ITEMS.

Payment will be made under:

Add the following:

Pay Items

Pay unit 557(03)A – Untreated structural timber & lumber…..………………… LS 557(03)B - Untreated structural timber & lumber…………………….. LS

557(04) Treated structural timber & lumber ……………………… LS

96 SPS 557

-2 (1/20/10)