508.01 508-1 SECTION 508 TIMBER STRUCTURES DESCRIPTION
508.01 This work consists of the construction of timber structures and timber portions of other
structures per these specifications and in conformity with the lines and grades shown on the plans or established. MATERIALS
508.02 Sawn lumber and timber shall conform to AASHTO M 168. Timber shall be Douglas Fir of
the coast region or Southern Yellow Pine. “Native” timber may be used when noted on the plans. “Native” timber shall be Red Cedar, Douglas Fir of the inland region, Lodgep ole Pine, Ponderosa Pine, Spruce, as listed and described in AASHTO M 168, or any other native wood specifically approved for the intended purpose. All timber shall be of the grade or shall meet the working stresses shown on the plans. Timber used in non- structural applications, whose working stresses are not shown on the plans, shall be graded to produce a working stress of 1,000 pounds per square inch on the extreme fibers when subjected to bending and 800 pounds per square inch when subjected to compression parallel to the grain. Material of equal or greater stress values may be used. All lumber shall be manufactured per Product Standard 20 -70 as published by the Department of Commerce and shall be grade- marked by a grading agency or have an accompanying certificate from a grading agency. The grading agency shall be certified by the Board of Review of the American Lumber Standards Committee.
508.03 Treated Timber. The preservative to be used shall be as specified on the plans. The
preservatives and entire treatment process shall be as described in AASHTO M 133 or by the American Wood Protection Association (AWPA) standards.
508.04 Inspection. All timber furnished shall be covered by a certificate of inspection issued
by the American Lumber Standard Committee (ALSC) or the International Accreditation Service (IAS) accredited inspection agency. Inspection approval shall be marked on each piece. Shop drawings shall be submitted per subsection 105.02 for all major structures and for other structures when specified. The Department may provide an inspector at the treating plant for material quality review and inspection of the treatment process for treated timber. The plant shall notify the Engineer sufficiently in advance of time of treating so that inspection may be arranged.
508.05 Hardware. Hardware shall include all bolts with necessary nuts and washers, timber
connectors, drift pins, dowels, nails, screws, spikes, metal pile protectors, steel anchor plates and all other metal fastenings as shown on the plans. Bolts shall conform to the re quirements of Section 509. Bolts over 12 inches long shall be threaded at least 4 inches. Drift bolts, spikes, boat spikes and other spikes shall be wrought iron or steel. Washers shall be standard cast iron ogee or malleable cast washers. Timber connectors and common nails shall be of the type and size specified on the plans. All hardware, except timber connectors and common nails, shall be galvanized per AASHTO M 232. 508.06 508-2 CONSTRUCTION REQUIREMENTS
508.06 Timber for the various portions of the structure shall be treated or untreated as
stipulated on the plans. Treated timbers shall not be sized or trimmed in the field, except when ordered. The Contractor shall not make temporary use of treated timber. All pieces that have been field cut shall be treated per AWPA Standard M4. Untreated stringer ends shall be separated at least 1/2 inch and shall be secured to the timber where they rest. Sway bracing shall be securely bolted to piling or post and caps as shown on the plans. Treated filling pieces shall be used in lieu of framing or dapping to bring bracing into a plane. Bulkheads, where required, shall be full size timber. Posts for framed bents shall be of the proper length for their position and provide an even bearing on cap and sill. All untreated caps shall be sized over the piles or posts to a uniform thickness and even bearing on piles or posts. Caps shall be within 1/4 inch of nomin al depth before treatment and may be surfaced on the vertical grain face. Before the timber capping is placed, a No. 20 gauge galvanized sheet metal cap shall be placed on each pile per the plans. In lieu of the sheet metal cap, three layers of heavy burlap may be used. Each layer of burlap shall be cut square to a dimension of 12 inches greater than the diameter of the pile head and shall be thoroughly swabbed with hot asphalt. The overhanging ends shall be turned down and secured to the pile with galvanized wire. The entire wrapping shall then be swabbed with a heavy application of hot asphalt. Longitudinal X -braces shall be properly framed and secured to piles or posts. Truss and bent timbers shall be cut and framed in such manner that they will have even bearing over the entire contact surface of the joint. Blocking or shimming will not be allo wed in making joints. Open joints will not be accepted. Stringers shall not be more than 1/4 inch off nominal size, before treatment. Floors shall be constructed as shown on the plans. The plank shall be secured to each stringer with two 7 -inch spikes. Half-inch cracks between planks shall be left in plain plank floors without surfacing. Laminated floors shall be secured as shown on the plans.
508.07 Holes and Bolts. All holes bored shall be treated per AWPA M4. Holes drilled for
drift bolts shall be 1/32 inch smaller than the diameter of the bolt. All other holes shall be bored to such size as to ensure a snug fit. Unless otherwise designated, all bolts shall be provided with two ogee washers .
508.08 Painting. All paint shall conform to the requirements of Section 708. Timber to be
painted shall be surfaced on four sides and shall be cleaned immediately preceding painting. New timber to be painted shall receive one coat of primer. “White Wood Primer” shall be used when the surface is to be finished with “Outside White Paint.” For “Exterior Black Paint,” the specification paint shall be thinned by adding one part linseed oil and one part turpentine to eight parts paint for use as a primer. The surfaces of all untreated timber to be painted shall be primed with one coat of primer immediately after the material is delivered to the project. Unless otherwise designated, pieces shall be primed as specified for the finish coat of paint, or “White Wood Primer” shall be used when additional painting is not required. Untreated timber will not require additional priming. 508.09 508-3 All handrails and handrail posts shall be of untreated timber and shall be painted as described hereafter. Contact surfaces shall receive the primer and one coat of paint before placing handrails. Parts specified, parts shown on the plans, and all exposed non -galvanized iron and steel shall, after the prime coat, be given two coats of the specified paint, which shall be thoroughly brushed in. Paint shall be applied only to thoroughly dry surfaces. A ll previous coats shall have thoroughly dried before subsequent coats are to be applied. Portions to be painted above the wheel guards or top wales shall be painted white and those portions below the wheel -guards or top wales to be painted shall be painted black.
508.09 Structure Number . The location, letters, figures, and paint used for stenciling shall be
per the plan details. METHOD OF MEASUREMENT
508.10 Timber will be measured by the thousand feet board measure [MFBM ] actually
incorporated in the structure and shall include hardware unless otherwise designated on the plans. BASIS OF PAYMENT
508.11 The accepted quantities will be paid for at the contract unit price for each of the pay
items listed below that appear in the bid schedule. Payment will be made under: Pay Item Pay Unit Untreated Timber MFBM Treated Timber MFBM Structure excavation and structure backfill will be measured and paid for per Section 206. Timber piling will be measured and paid for per Section 502. 508.11 508-4 THIS PAGE INTENTIONALLY LEFT BLANK 509.01 509-1 SECTION 509 STEEL STRUCTURES DESCRIPTION
509.01 This work consists of furnishing, fabricating, erecting, and painting structural steel per
these specifications and to the dimensions, shapes, and design shown on the plans, and to the lines and grades established. Structural steel shall include galvanizing, bolting, welding, special and alloy steels, electrodes, and steel forgings. When the term “main stress carrying members” or “main members” is used, it shall include girder web and flange plates and splice plates, pier and abutment diaphragm web and flange plates and splice plates.
509.02 The latest edition of the AASHTO LRFD Bridge Design Specifications, with current
interim specifications, will govern the design of steel bridges, unless otherwise noted on the plans. Welding and fabrication of steel structures shall conform to the Bridge W elding Code ANSI/AASHTO/AWS D1.5, as amended by the contract documents. When AWS D1.5 is cited in the Standard Specifications, the reference shall be to the latest edition of the Bridge Welding Code. MATERIALS
509.03 Structural Carbon Steel. Structural carbon steel for bolted or welded construction shall
conform to AASHTO M270 (ASTM A709) Grade 36. Material supplied for main members in tension as designated in the Contract shall meet a longitudinal Charpy V -notch (CVN per AWS D1.5. Testing sha ll be per AASHTO T 243 (ASTM A673). The H frequency of heat testing shall be used.
509.04 High-Strength Low -Alloy Structural Steel. High -strength low -alloy structural steel for
welding shall conform to the following requirements : High-Strength Low -Alloy Columbian -Vanadium Steels of Structural Quality, Grade 50 shall meet the requirements of AASHTO M270 (ASTM A709). High-Strength Low -Alloy Structural Steel with 50 ksi Minimum Yield Point to 4 inches thick shall meet the requirements of AASHTO M270 (ASTM A709). Steel conforming to AASHTO M270 (ASTM A709) Grade 50W shall not be painted unless otherwise shown on the plans. Material supplied for main members in tension, as designated in the Contract, shall meet the longitudinal Charpy V -notch (CVN) tests as specified for Zone 2 in AASHTO M270.
509.05 Self-Weathering Tubing. Self-weathering structural steel tubing shall conform to ASTM
A847, Cold -Formed Welded and Seamless High Strength, Low Alloy Structural Tubing with Improved Atmospheric Corrosion Resistance.
509.06 Structural Tubing. Steel base metal to be used for tubular structures, including bridge
rail, shall conform to the plans or AWS D1.1. The grade and specification to be used shall be specified in the Contract.