1031TIMBER STRUCTURES

1031.1DESCRIPTION —This work is the construction of all timber structures except hardwood glue -

laminated (glulam) structures.

1031.2MATERIAL—

Red Maple, Northern Red Oak, Red Oak, Mixed Oak, White Oak, and Yellow Poplar. Provide Select Structural, No. 1 or No. 2 grade lumber and timber. Provide sawn lumber and timber conforming to the Specifications for Structural Timber, Lumber and Piling, AASHTO M 168. Certify as specified in Section

106.03(b)3

Accept only pieces consisting of sound wood, free from decay. Avoid boxed heart timber. Use structural timber complying with the American Softwood Lumber (ASL) Standard PS 20 -70 for manufacture of dressed -sized lumber and timber products. Grade Douglas Fir -Larch and Hem -Fir using West Coast Lumber Inspection Bureau (WCLIB) or Western Wood Pro ducts Association (WWPA) inspection rules. Grade Douglas Fir -Larch (North) and Hem -Fir (North) using National Lumber Grades Authority (NLGA) inspection rules. Grade Southern Pine according to Southern Pine Inspection Bureau

Oak, Mixed Oak, and White Oak according to Northeast Lumber Manufacturer's Association (NELMA) grade rules. Grade Yellow Poplar according to Northern Softwood Lumber Bureau (NSLB) rules. Adequately protect structural timber during transport. Accept only kiln dried dimension lumber at 15% average moisture content, and 19% maximum moisture content. Accept only solid sawn timbers that have been air seasoned or dried to an average moisture content not exceeding 19%. Accept only softwood glue-laminated timbers with a maximum 16% moisture content. Preservative treat lumber and timber by pressure treatment process according to the AWPA C1, “All Timber Products - Preservative Treatment by Pressure Processes.” Treat structural timbers for highway/bridge construction according to AWPA C14, “Wood for Highway Construction - Preservative Treatment by Pressure Processes.” Minimum retention of creosote preservative for wood species not covered under AWPA C14 is 11.6 pounds per cubic foot. Treat piles as specified in Section 1005.2(a) and according to the AWPA C3, “Piles - Preservative Treatment by Pressure Processes.” Provide treated lumber and timber products with permanent symbol imprints or documentation to identify the treating company, treatment type, year of treatment, and certification of conformance with AWPA. Certify as specified in Section 106.03(b)3. Accept treated structural timber that conforms to appropriate recommended AWPA treatment requirements.

Glued Laminated Timber,” Section 4.4. Provide wet -use adhesives. Certify as specified in Section

other metal fasteners, and wire rope as necessary. Provide bolts and nuts as specified in Section

1105.02(c)1. Provide machine head bolts and nuts of regular hexse ries and coarse thread series, Class

6g and 6H (Class 2) tolerances, all conforming to applicable ANSI Standards. Provide cast iron Ogee, malleable iron, plate, or cut washers, as indicated. Galvanize all hardware except cast and mallea ble iron. Certify as specified in Section 106.03(b)3.

1.a Mechanically Laminated Panels. Perform all possible fabrication of mechanically laminated members before preservative treatment. Treat mechanically laminated girders and deck panels for highway construction according to AWPA C14.

1.b Glued laminated Members. Fabricate structural glued laminated softwood timber according to ANSI/AITC 190.1, “Structural Glued Laminated Timber,” and AITC -117, “Manufacturing, Standard Specifications for Structural Glued Laminated Timber of Softwood Species.” Treat glued laminated timbers for highway construction according to AWPA C14.

on the structural drawings, and with tolerances according to the ANSI/AITC A190.1 (AITC 113, “Standard for Dimensions of Structural Glued Laminated Timber”) or tolerances as follows:

• Width. ±1/8 inch of the indicated width.

• Depth. ±1/8 inch per foot of indicated depth.

• Length. ±1/8 inch up to 20 -foot length with a ±1/8 -inch allowance for every 20 feet of additional length.

• Squareness. Provide a cross section for all glued laminated structural members which is square within ±1/8 inch per foot of depth of member unless a special shape is indicated.

• Beam Camber. ±1/4 inch for lengths up to 20 feet. Add ±1/8 -inch allowance for each additional 20 foot length.

Provide industrial appearance grade glued laminated timbers according to AITC 110, “Standard Appearance Grades for Structural Glued Laminated Timber.” Accept only glued laminated timbers in standard dressed widths according to AITC 113.

• Asphalt Wearing Course. Section 413.2

preservatives with hardwood lumber and timber.

1031.3CONSTRUCTION—

exposure to the elements if stored for prolonged periods of time. Store material so that it can be readily inspected.

Handle in a manner to avoid injury or breakage. Handle treated lumber with nylon or other non-damaging rope slings. Do not use cant hooks, peaveys, or other sharp instruments in handling treated timber. Provide corner protection for banded material. The Department will reject treated lumber unduly injured in handling.

bearing of joints over the entire contact surfaces. Make joints without shimming. Field drill only as indicated or as allowed.

AWPA M4, “Standard for the Care of Preservative -Treated Wood Products.” Plug unfilled holes, after field treatment, with treated timber plugs. Bore holes in untreated lumber 1/16 inch in diameter less than the pin or dowel. Bore holes 1/16 inch in diameter larger than the bolt. Bore holes for lag screws not larger than the base of the thread. Bore holes in small timbers with the same diameter as the spike shank when necessary to prevent splitting. Do not field drill or nail, except for railing.

split ring, shear plate, or spike grid. Install split ring and shear plate types in precut grooves of dimensions as indicated or as recommended by the manufacturer. Force spike grids into t he wood so that timbers are in firm contact. Use pressure equipment that does not damage the wood. High -strength bolts or rods fitted with low friction ball-bearing washers made for this purpose may be used. Replace the high -strength bolts with specified bolts for the final installation. Embed all connectors of this type at a joint simultaneously and uniformly. Cut connector grooves in timber concentric with the bolt hole, conforming to the cross-sectional shape of the rings, and providing a snug fit. Supply an inside groove diameter larger than nominal ring diameter so that the ring will expand slightly during installation. (See Table A)

timber bolts with economy type heads) and nuts that would otherwise come in contact with wood. After final tightening, lock the nuts of all bolts.

indicated, and as specified in Section 1005.3. Make cut-offs accurately to ensure uniform bearing between the sills and piles of a bent. Treat cut pile ends according to AWPA M4.

Construct concrete pedestals for the support of framed bents, as specified in the applicable portions of Section 1001.3. Finish pedestals carefully to provide full and even bearing for sills or posts. Provide for true and even bearing of sills on mudsills, piles, or pedestals. If possible, remove all earth from contact with sills to provide for free air circulation around them.

supporting posts or piles, and to secure an even alignment of their ends. Secure all sills as indicated. For sills secured using drift bolts, place drift bolts approximately in the center of the post or pile.

post, or cap. Furnish bracing of sufficient length to provide a minimum distance of 8 inches between the outside bolt and the end of the brace.

TABLE A Typical Dimensions of Timber Connectors (dimensions in in.) Split Rings Size 2 1/2 in. 4 in. Split ring Inside diameter at center when closed Thickness of metal at center Depth of metal (width of ring)

2.500 0.163 0.750

4.000 0.193 1.000 Groove Inside diameter Width Depth

2.56 0.18 0.375

4.08 0.21 0.50 Bolt diameter Bolt hole diameter 1/2 9/16 3/4 13/16 Washers, standard Round, cast or malleable iron, diameter Round, mild steel Diameter Thickness Square plate, mild steel Length of side Thickness

2 5/8

1 3/8 3/32

1/8

5/32

3/16 Shear Plates Size 2 1/2 in. 2 1/2 in. 4 in. 4 in. Shear plate material

Diameter of plate Diameter of bolt hole Thickness of plate Depth of flange Pressed steel

2.62 0.81 0.172 0.42 Light gage

2.62 0.81 0.12 0.35 Malleable

4.03 0.81 0.20 0.64 Malleable

4.03 0.94 0.20 0.64 Use steel straps or shapes, for use with shear plates, designed according to accepted engineering practices. Hole diameter in straps or shapes for bolts 13/16 13/16 13/16 15/16 Circular dap dimensions A B C D E F G H I

2.63 — 0.81 — 0.19 0.45 0.25 — 2.25

2.63 1.07 0.81 0.65 0.13 0.38 0.14 0.34 2.37

4.03 1.55 0.81 0.97 0.27 0.64 0.22 0.50 3.49

4.03 1.55 0.94 0.97 0.27 0.64 0.22 0.50 3.49 Bolt hole—diameter in timber 13/16 13/16 13/16 15/16 Washers, standard Round, cast or malleable iron, diameter Round, medium steel, minimum Diameter Thickness Square plate Length of side Thickness

5/32

1/4

5/32

1/4

5/32

1/4

3 1/2

2 1/4 11/64

1/4

the floor on the stringers. Use butt joints for outside stringers, centered over caps of floor beams. Lap interior stringers to take bearing over the full width of cap or floor beams at each end. Frame cross-bridging between stringers neatly and accurately, and fasten securely. Provide for full bearing of each end of cross -bridging members against the sides of stringers. Unless otherwise directed, place cross-bridging at the center of each span and at supports.

Provide for even bearing of the deck on all stringers at piers as indicated, but allow no less than 1/2 inch clearance between butt ends to allow for air circulation. Treat all field drilled holes or reamed holes before installation of hardware according to AWPA M4. Treat all field-drilled holes before installing diaphragms. Provide for close fit (full bearing) of diaphragm between stringer beams. Place diaphragms or cross bracing as indicated.

accurately and as indicated.

decks. Field drill or ream connections only if directed. Treat all field -drilled or reamed holes according to AWPA M4.

Using pressure process, treat portions of rail posts that are to be embedded in earth or concrete and where faces of timber bulkheads will be in soil contact, with a 11.9 pounds per cubic foot retention of creosote preservative for softwoods and 11.6 pounds per cubic foot to 11.9 pounds per cubic foot retention of creosote for hardwoods. Apply a two -coat finish sealer to treated structural timber railings where prolonged exposure to direct human contact is likely. Acceptable sealers include latex epoxy, urethane, shellac, or other finishes with effective coating agents that adhere to treated rails. When framing, cutting, or boring of treated timber is performed after treatment, swab all cuts, daps, and holes thoroughly with two applications of accepted wood preservative treatments according to AWPA M4.

Stress to 100% of the required tensioning force at the time of installation (Stage 1). Restress to 100% of the required tensioning force 1 week after completion of Stage 1 (Stage 2). Restress to 100% of the required tensioning force 4 to 8 weeks after completion of Stage 2. Pressure inject protective sheathing with noncorrosive material or with material containing a corrosion inhibitor.

excretions and surface residues of the treatment solution before constructing the asphalt leveling course. Spread a blotter of fine material (silt and sandy silt) over the surface. Use a mixture consisting of 20% crushed material passing a 2.36 mm (No. 8) sieve and 80% material passing a 150 µm (No. 100) sieve. Spread at a rate of 5 kg/m2 to 8 kg/m2 (10 pounds per square yard to 15 pounds per square yard). Broom off the blotter material. Repeat process until the surface is free of exudates. Construct the Superpave Asphalt Mixture Design, leveling course as indicated and as specified in Section

413.3Use only non-vibratory rollers for compaction of the Superpave Asphalt Mixture Design, leveling course

For stressed-laminated timber decks, prepare the Superpave Asphalt Mixture Design, leveling course surface and construct waterproofing membrane as indicated. Construct the Superpave Asphalt Mixture Design, surface course as specified in Section 413.3. Use only non-vibratory rollers for compaction of the Superpave Asphalt Mixture Design, surface course. Provide geotextile Class 4 fabric as specified in Section 735, for glued laminated timber decks. No leveling course is necessary for glued laminated decks.

1031.4MEASUREMENT AND PAYMENT—Lump Sum

• Asphalt Wearing Course. Section 413.4