00570.00 564 Section 00570 - Timber Structures
Description
00570.00Scope - This Work consists of fur nishing and installing timber and glue laminated timber in
Bridges and other timber Structures as shown or directed. Timber and lumber will be identified as timber in this Section. The terms "hardware" and "fastenings" include nails, spikes, bolts, washers and nuts, dowels, lag screws, timber connectors, truss rods and shoes, and all other metal used in timber construction.
Materials
00570.10Materials - Furnish Materials meeting the following requirements:
Galvanizing ........................................................................................... 02530.70
When preservative treatment of timber is required, the Plans or Special Provisions will indicate the type and kind of treatment.
00570.11Metal Parts - Hot-dip galvanize all hardware and all other metal parts after fabrication
according to 02530.70 or coat all hardware and all other metal parts after fabrication according to
00570.12Timber Fabrication :
Use either split ring or shear plate timber connectors as specified. Install in precut grooves of dimensions as recommended by the manufacturer. Fabricate all members including holes, grooves, and special cuts, requiring timber connectors before treatment. When prefabricating from templates or shop details, bore bolt holes not more than 1/16 inch from specified location and perpendicular to the face of the timber . Bore bolt holes according to 00570.41. Submit unstamped Working Drawings for review, according to 00150.35, for prefabricated material before fabrication.
00570.13Timber Storage - Store timber on the site in orderly piles or stacks. Provide protection
from the weather or direct sun by a suitable covering.
Open-stack untreated timber on supports at least 12 inches above the ground surface and sticker to permit air circulation between the tiers and courses. Provide 1/2 inch thick by 1 1/2 inch wide stickers. Place stickers with the wide face bearing against the timber and at a spacing that provides adequate support for the members for their full length. Align stickers vertically to prevent uneven support and warp during storage.
Store timber after fabrication in a manner that prevents alignment changes of the members before assembly. 00570.42 565 Store, protect, and handle glue laminated timber according to the American Institute of Timber Construction AITC 111 "Recommended Practice for Protection of Structural Glued Laminated Timber during Transit, Storage, and Erection".
Construction
00570.40Treated Timber - Handle treated timber that prevents dropping, breaking of outer fibers,
bruising, or penetrating the surface with tools. Use nylon slings to handle treated timber. Do not use cant hooks, peaveys, pikes or hooks. When treated timbers are to be placed in a marine or brackish environments, field treated and untreated cuts, borings and other joint framings are not allowed below high-water elevation.
Do not cut, fr ame, or bore treated timber after treatment unless necessary. If untreated wood is exposed by cutting, planing, sanding, or any other means, trim all cuts and abrasions in timber, and cover with two applications of a field preservative according to 02190. 30.
Pour field preservative into all holes bored after treatment, or treat the holes with field preservative with an approved pressure hole treater. Treat all unfilled holes with field preservative and plug with treated plugs. Field treat according to 0 2190.30 and the recommendations of the manufacturer.
When forms or temporary braces are attached to treated timber with nails or spikes, fill the resulting holes by driving larger size galvanized nails or spikes flush with the surface, or plug holes as required for unfilled bolt holes.
00570.41Fasteners:
• Bore holes for drift pins, drift bolts, and dowels either 1/32 inch smaller than or the same size of the actual pin diameter. • Bore holes for bolts 1/32 inch to 1/16 inch larger than the bolt diameter. Accurately align holes in main members and side plates. Do not force drive bolts. • Bore holes for truss rods with a bit 1/16 inch larger than the rod. • Drive nails and spikes with sufficient force to set the heads flush with the surface of the wo od. Deep hammer marks in wood surfaces are evidence of poor Work and sufficient cause for removal of damaged material. • Bore holes for lag screws in two parts as follows: • Bore the lead hole for the shank the same diameter as the shank and the same depth as the length of the unthreaded shank. • Bore the lead hole for the threaded portion a diameter equal to approximately two-thirds of the shank diameter. • Use a malleable iron washer of the size and type designated under all bolt heads and nuts in contact with w ood except under button-head bolt heads. • Lock all nuts after final tightening with a second nut or use self -locking nuts. • Countersink where smooth faces are required. Coat recesses formed for countersinking with field preservative according to 02190.30 and the manufacturer's directions. After the bolt or screw is in place, fill horizontal recesses with asphalt roofing cement. • Install all fasteners and connections according to the manufacturer's recommendations.
00570.42Framing - Cut and frame all timber to a close fit so that the joints have even bearing over
the entire contact surfaces. Shimming is not allowed. 00570.43 566
allowed.
Select the piles for any one bent as to size, to avoid undue bending or distortion of the sway bracing. Distribute the piles of varying sizes to secure uniform strength and rigidity in the bents of any given Structure .
pedestals so the sills or posts support framed bents with even bearing.
Fasten posts to sills as shown. Remove all earth from contact with all timber so there will be free air circulation around them.
posts or piles.
00570.43Stringers - Place stringers according to the following:
• Knots near edges will be in the top portions of the stringers. • Outside stringers may have butt joints, but lap interior stringers to take bearing over the full width of the floor beam or cap at each end. Do not extend the stringer end more than 6 inches beyond the floor beam or cap. • Separate the lapped ends of untreated stringers at least 1/2 inch and securely fasten where shown or specified. • Stagger joints when stringers are two spans in length. • Frame cross-bridging between stringers as shown, with full bearing at each end against the sides of stringers, and securely toe- nail with at least two nails in each end.
00570.44Decking - Unless otherwise shown or specified, construct decking with 4 inch x 12 inch
planking and covering materials.
Place planking heart side down with 1/4 inch opening between planks for seasoned Material and with tight joints for unseasoned Material. Spike planks securely to each stringer with a minimum o f one 3/8 inch x 8 inch spike placed 3 inches in from each edge.
• 2 inch x 2 inch timber strips, placed transverse to the planking and nailed with 16d galvanized common nails at 12 inch centers. Cover deck with a Level 2, 1/2 inch ACP wearing surface according to Sections 00744 and 00745, as applicable; or • 1 inch thick tongue and groove structural CD exterior grade plywood. Nail the plywood with face grain parallel to stringers using 10d galvanized or zinc coated ring shank nails. Place nails at 6 inch centers along all edges and 12 inch maximum centers intermediate. Fasten expanded metal grillage with a minimum opening of 1/4 inch and a minimum thickness of 1/8 inch to the top of the plywood for the entire R oadway area. Minimum fastening shall be at 12 inch centers each direction using 8d galvanized comm on nails. Cover deck with a Level 2, 1/2 inch ACP wearing surface according to Sections 00744 and 00745, as applicable. 00570.90 567
00570.45Wheel Guards and Railings - Frame wheel guards and railing as shown, and erect true
to line and grade. Unless otherwise specified, provide wheel guards, rails, and rail posts that are surfaced on four sides (S4S).
Lay wheel guards in sections not less than 12 feet long unless otherwise shown.
For trusses, build railings after the removal of the falsework and the adjustment of the trusses to correct alignment and C amber.
00570.46Trusses - Finished trusses shall show no irregularities of line. Chords shall be straight and
true from end to end in horizontal projection and show a smooth curve through panel points conforming to the correct Camber. Fit all bearing surfaces accurately. Uneven or rough cuts at the points of bearing will be cause for rejection of the piece containing the defect.
00570.47Coating - When specified, coat timber Bridges according to the manufact urer's
recommendations. Kiln dry all timber to 19 percent before coating.
Measurement
00570.80Measurement - The quantities of all timber, except piling and glue laminated timber,
incorporated into the permanent, finished Structure , will be measured o n the volume basis, based on the nominal dimensions of the members and the actual dimensioned length. No allowance will be made for waste.
The quantities of glue laminated timber members will be measured on the volume basis, based on the net dimensions o f the members.
Driven piles will be measured according to 00520.80. Asphalt concrete wearing surface will be measured according to 00744.80 and 00745.80, as applicable.
Payment
00570.90Payment - The accepted quantities of Work performed under this Section will be paid for
at the Contract unit price, per unit of measurement, for the following items:
Pay Item Unit of Measurement
Payment will be payment in full for furnishing and placing all Materials, and for furnishing all Equipment , labor, and Incidentals necessary to complete the Work as specified.
Driven piles will be paid for according to 00520.90.
Asphalt concrete wearing sur face will be paid for according to 00744.90 and 00745.90, as applicable.
No separate or additional payment will be made for hardware, fastenings, preservative treatment, or coatings.