712TIMBER STRUCTURES

712.01Description

This work shall consist of furnishing the materials for and the construction of timber structures, such parts of other structures which are of timber, and wood plank floors for structures in accordance with 105.03.

MATERIALS

712.02Materials 10

Materials shall be in acco rdance with the following:

Iron Castings................................................................ 910.05(b) Lumber and Timber (Treated) ..................................... 911.02 Lumber and Timber (Untreated) .................................. 911.01 Malleable Iron Castings ............................................... 910.05(d) Preservatives ................................................................ 911.02(h) Steel Castings .............................................................. 910.05(a) Structural Steel ............................................................ 910.02 Waterborne Finish Paint .............................................. 909.02(d) 20

Machine bolts, drift bolts, and dowels shall be medium steel. Machine bolts shall have square heads and nuts, unless otherwise specified. Nails shall be full-barbed, heavy, bright, flat-head, car nails. Lumber and timber shall be treated or untreated. Rods, plates, bars, and shapes shall be structural steel. Castings shall be steel or iron. Washers may be cast O. G. or malleable castings or they may be cut from medium steel plates. Spikes shall be cut, wire, or boat spikes. Spikes, bolts, dowels, washers, and lag screws shall be black or galvanized.

CONSTRUCTION REQUIREMENTS 30

712.03General Requirements

The ground beneath and in the immediate vicinity of all stored material shall be cleaned of weeds and rubbish and kept well drained. Lumber and timber at the site of the work shall be stored in piles. Untreated lumber shall be open stacked at least 12 in. 712.03

above the ground surface, arranged to shed water and prevent warping, and protected by a weatherproof covering when so required. Treated timber and piling shall be closed-stacked so that warping is prevented, and the tops of the stacks are covered. Treated timber shall be handled carefully without sudden dropping, breaking of outer fibers, bruising, or penetrating surfaces with tools. It shall be handled with rope slings. 40 Canthooks, peaveys, spikes, or hooks shall not be used. Treated piling may be handled with chains.

Workmanship shall be first-class throughout. Competent bridge carpenters shall be employed. All framing shall be true and exact. Nails and spikes shall be driven with just sufficient force to set the heads flush with the surface of the wood. Deep hammer marks in wood surfaces will be considered evidence of poor workmanship and sufficient cause for the dismissal of a worker causing them.

In structures of untreated timber, the e nds, tops, and all contact surfaces of sills, 50 caps, floor beams, stringers, end joints, cont act surfaces of bracing, the back faces of bulkheads, and all timber which is to be in contact with earth, road material, or other timber shall be field-treated with coppe r naphthenate in accordance with AWPA Standard M4 before being assembled. Countersinking shall be done where smooth faces are required. The recesses formed by co untersinking shall be field-treated with copper naphthenate in accordance with AWPA Standard M4 after the bolt or screw is in place.

All cuts in treated piles or timber, all abrasions, after having been trimmed, and all holes for bolts or other appurtenances shall be field-treated with copper naphthenate 60 in accordance with AWPA Standard M4. Insofar as practicable, cutting, framing, and boring of timber to be treated, except pile cut-offs, shall be done before treatment.

All lumber and timber shall be cut accurat ely and framed to a close fit in such manner that joints will have even bearing over the entire contact surfaces. Mortises shall be true and even for their full depth and tenons shall fit snugly. Shimming will not be allowed in making joints nor will open joints be accepted. Timbers requiring an exact fit shall be matchmarked.

Holes for bolts, dowels, rods, and lag screws shall be bored as follows: 70

that of the bolt or dowel to be used,

the bolt or dowel,

712.03

the screw diameter to the point of the screw.

A washer of the size and type specifie d shall be used under each bolt head and under each nut which would come in contact with wood. Any portion of a bolt projecting more than 1/4 in. beyond the nut shall be cut off. The threads of each bolt shall be checked at the face of the nut after the nut has been finally tightened. The ends of bracing shall be bolted through the pile, post, or cap with bolts of no less than 5/8 in. in diameter. Intermediate intersections shall be bolted or spiked with wire or boat 90 spikes as shown on the plans.

712.04Caps

Timber caps shall have an even and uniform bearing over the tops of supporting posts or piles and shall have their ends ev enly aligned. All caps shall be secured by drift bolts of no less than 3/4 in. in diameter extending at least 9 in. into the approximate center of posts or piles. Pile heads, after being cut to receive the caps and prior to placing the caps, shall be treated with copper naphthenate in accordance with AWPA Standard M4 to prevent decay.

712.05Stringers

Stringers shall be sized at bearings and so placed in position that any knots at or near edges are in the top portion. Outside stringers may have butt joints with the ends cut on a taper. Interior stringers shall be lapped to take bearing over the full width of the floor beam or cap at each end. The lapped ends of untreated stringers shall be separated at least 1/2 in. for the circulation of air and shall be securely fastened to the cap by drift bolting where specified. Where stringers are two panels in length, the joints shall be staggered. Cross-bridging between stringers shall be neatly and accurately framed and securely toenailed with at least two nails in each end.

712.06Bents

Untreated timber, if used for mudsills shall be heart cedar, heart cypress, redwood, or other approved durable timber. Mudsills shall be embedded firmly and evenly to solid bearing and tamped in place. Concrete pedestals for the support of framed bents shall be carefully finished so that the posts or sills take even bearing on them. The sills or posts shall be anchored to pedestals with dowels and the dowels set when the pedestals are poured. They shall be no less than 3/4 in. in diameter and shall project at least 6 in. above the top of each pedestal. Sills shall have true and even bearing on mudsills, grillages, piles, or pedestals. They shall be drift-bolted to mudsills or piles with bolts no less than 3/4 in. in diameter and extend into the mudsills or piles at least 120 6 in. When feasible, all earth shall be removed from contact with sills to enable free circulation of air around them.

Posts shall be fastened to pedestals with dowels of no less than 3/4 in. in diameter extending at least 6 in. into the posts. Posts shall be fastened to sills, as shown on the plans, by means of drift bolts of not less than 3/4 in. in diameter driven diagonally through the base of the post, and extending at least 9 in. into the sill, or by means of 712.06

dowels of no less than 3/4 in. in diameter extending at least 6 in. into posts and sills. Pile bents shall be driven in accordance with 701.

712.07Wheel Guards and Railings

These shall be framed and erected true to line and grade. Wheel guards and rails shall be surfaced as shown on the plans. Wheel guards shall be laid in sections of no less than 12 ft in length.

712.08Painting

Paint shall be applied to untreated lumber and timber as shown on the plans or as otherwise specified. Lumber or timber treated with preservative shall not be painted, unless otherwise specified. The color shall be as specified.

Surface preparation shall be the removal of all contamination such as oil, grease, dirt, foreign matter, rust, mold, mildew, and sealers. Knots and pitch streaks shall be scraped or burned, and sanded. All nail holes or small openings shall be caulked with a general purpose caulking compound.

The surfaces shall be painted with one coat of waterborne finish paint. The paint shall be applied by brush or roller only and at the rate recommended by the manufacturer. All finishes shall be uniform in texture and color. If a painted surface is unsatisfactory, the paint shall be removed and the surface shall be cleaned and repainted or corrected as may be directed. 150

At the end of each work day, paint stains and splatters shall be removed from all surfaces not intended to receive the paint applied for that day.

712.09Single-Ply Plank Floors

These floors shall consist of a single thickness of plank supported by stringers or joists. The planks shall be laid heartside down with 1/4 in. openings for seasoned material and with tight joints for unseasoned material. Each plank shall be fastened securely to each joist or stri nger. The planks shall be caref ully selected for thickness and laid so that a smooth riding surface is obtained. 160

712.10Two-Ply Plank Floors

These floors shall consist of two layers of wood planks supported by stringers or joists. Both courses shall have been pressu re treated in accordance with 911.02. The top course shall be laid pa rallel to the roadway centerl ine with each piece fastened securely to the lower course. The lower course shall be fastened as provided above for single-ply. Joints shall be staggered at least 3 ft. Ends shall be fastened securely. If required, the outer ends of the top planks shall be beveled at each end of the bridge.

712.11Method of Measurement 170

Structural timber and lumber, both treated and untreated, will be measured by the 1,000 board foot measure. Planks for floors will be measured by the square foot. Computation of the amount of lumber and timber will be based on full size for rough 712.07

lumber and nominal size for dressed lumber on the shortest commercial lengths which may be used.

Metal parts, other than hardware, w ill be measured by the pound computed in accordance with 711.73(b). Bolts, dowels, washers, nails, spikes, and lag screws will be classed as hardware.

712.12Basis of Payment

The accepted quantities of lumber and timber will be paid for at the contract unit price per 1,000 board foot measure for lumber and timber, either treated or untreated as specified. Plank floors will be paid for at the contract unit price per square foot for plank floors of the ply specified. Metal parts will be paid for at the contract unit price per pound.

Payment will be made under:

Pay Item Pay Unit Symbol 190

Lumber and Timber, Treated ..................................................... MFBM Lumber and Timber, Untreated ................................................. MFBM Metal Parts ................................................................................. LBS Plank Floors, ____ Ply .............................................................. SFT

The cost of preservative treatment, hard ware, painting, and necessary incidentals shall be included in the cost of the pay items.