for Highway Construction Page 672 of 71 5 SECTION 710 – TIMBER AND PRESERVATIVES
710.01 Structural Timber and Lumber .
Provide Douglas Fir or Larch structural timber and lumber of the grade specified. Ensure grade of structural timber and lumber is determined using the current version of the Western Wood Products Association (WWPA) standard grading rules of western lumber. Ensure wood is incised and treated to meet the American Wood Preservers Association (AWPA) StandardU1, Commodity Specification A: Sawn Products.
710.02 Wood Sign Posts .
Provide sign posts surfaced four sides (S4S) and free of wane and decay. Ensure ends are cut square and the post incised on all 4 sides before treating. Checks will not be more than 1/4 inch in width. The E ngineer will not accept twisted pieces. Ensure sweep is limited to 1 inch per 10 feet. Incise in accordance with AWPA U1, Commodity Specification A: Sawn Products, and pressure treat as specified in 710.09. Provide treated and graded Douglas F ir or Hem- Fir sign posts. Use the current version of the West Coast Lumber Inspection Bureau (WCLIB) or the WWPA to meet the following grades and requirements: Table 710.02- 1: Wood Sign Post Grades and Requirements Species Grade Douglas Fir 4” by 4” 85 percent of the sign posts free of heart center. Structural light framing, No. 2 grade in accordance with WCLIB paragraph 124c or WWPA paragraph 42.12. 4” by 6” 85 percent of the sign posts free of heart center. Structural joists and planks, No. 2 grade in accordance with WCLIB paragraph 123c or WWPA paragraph 62.12. 6” by 6” or 6” by 8” or 8” by 8” Posts and timbers, No. 1 grade in accordance with WCLIB paragraph 131b or WWPA paragraph 80.11. Hem -Fir 6” by 6” or 6” by 8” or 8” by 8” Posts and timbers, select structural in accordance with paragraph 131a WCLIB or paragraph 80.10 WWPA. Provide posts inspected and certified in accordance with the designated current grading and dressing rules of the WCLIB or the WWPA. Submit a certificate of inspection executed by the WCLIB, the WWPA, or the Pacific Lumber Inspection Bureau (PLIB ) at the time of delivery. Ensure certificates of inspection identify the destination or FOB for which the material is intended and each piece is inspected, certified, and stamped with an inspection mark. Such certification or grade marking does not constitute final acceptance of the material , and the Engineer may reject lumber or timber that does not meet specifications.
710.03 Timber Guardrail Posts and Timber Blockouts.
Provide rough surfaced 2 sides (S2S ) or 4 -sided (S4S) wood guardrail posts and wood blockouts. Do not exceed the size tolerance of plus or minus 1/4 inch for rough sawed blocks. Provide incising that meets AWPA U1, Commodity Specification A: Sawn Products, and pressure treat as specified in 710.09. for Highway Construction Page 673 of 71 5 Grade guardrail post and blockouts using WWPA standard grading rules for western lumber and the following: Table 710.03- 1: Guardrail Post and Blockout Grading Species Grade Douglas Fir or Larch No. 1 Grade Hem -Fir No. 1 Grade Pine (Lodgepole, Ponderosa, Idaho White, and Southern) No. 1 Grade Western Red Cedar No. 1 Grade The Engineer will reject an otherwise acceptable guardrail post with a thorough check, shake, or end split in the same plane or parallel plane as the bolt hole and extending from the top of the post to within 3 inches of the bolt hole, unless it is provided with a tight fastening across the separation centered 2 inches below the top of the post. Use a galvanized bolt fastener 1/2 inch in diameter with a galvanized washer under the bolt head and the nut. Treat holes for fastening in accordance with AWPA M 4.
710.04 Service Poles for Power .
Meet ANSI No. 05.1. The Contractor may use all species of Douglas Fir, Larch, Hemlock, and Pine. Treat poles as specified in 710.09.
710.05 Timber Piles .
1.Provide first quality timber piles Douglas Fir or Western Larch that meet ASTM D25.
2.Treated Piles. Treat as specified in 710.09.
3.Untreated Piles. Provide untreated piles with a high heartwood content and a diameter of heartwo od at least eight -tenths of the diameter at the butt.
4.Dimensions. Provide piles with a diameter at a section 3 feet from the butt and at the tip as specified in Table 710.05- 1 below.
5.Material used in or over aquatic environments will be produced in compliance with the Western Wood Preservers Institute’s (WWPI) “Best Management Practices for the Use of Treated Wood in Aquatic and Wetland Environments”. Material produced in compliance with the WWPI’s BMPs w ill require certification by an independent third party inspection agency as specified in the BMPs. Table 710.05 -1 – Bolt Diameter Length of Piles , feet Butt Diameter, in ch Tip Diameter , inch, minimum Under 40 12-18 8 40-60 13-18 7 Over 60 14-20 6 for Highway Construction Page 674 of 715 The Engineer will measure the diameter of the piles after peeling. When the pile is not exactly round, the Engineer will use the average diameters or the circumference divided by pi (3.14159) to determine the diameter. For structures , provide pile with the butt diameters and length as uniform as practical.
710.06 Service Poles for Illumination .
Provide poles thoroughly seasoned and treated, 35 feet long, rated Class 4, machine peeled, and that meet ANSI 05.1, except the number and size of knots and the sweep of the pole can be two- thirds that allowed by the ANSI specification. Provide treated poles as specifi ed in 710.09.
710.07 Pole Keys.
Provide thoroughly seasoned and treated pole keys , 5 feet long, have a 4- inch minimum dimension, and a minimum cross -sectional area of 25 square inches. Treat pole keys as specified in 710.09.
710.08 Posts for Bar bed or Woven Wire Fence .
Provide line posts with a minimum post circumference of 10 inches and install a minimum distance between opposite faces or between faces and an opposite corner of 3 inches. Provide posts for corner, terminal, or braces with a minimum circumference of 171/2 inches and install a minimum distance between opposite faces or between faces and an opposite corner of 4 inches. Pressure treat wood posts as specified in 710.09. The Contractor may use any species of Douglas Fir, Western Larch, Cedar, or Pine.
710.09 Preservative Treatment .
Provide treated timber and lumber requiring preservative treatment that meets the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) requirements as registered preservatives, AASHTO M 133, and AWPA standards and specifications. These specifications include the following:
1.Storing and curing the timber and l umber.
2.Wood preservatives.
3.Preservative treatment process.
4.Documenting the results of the treatment.
5.Inspection.
6.Testing.
7.Identification of properly treated timber. Treat timber and lumber in accordance with AWPA C14. Perform cutting, boring, chamfering, routing, surfacing, and trimming before treating. Treat with 2 liberal applications of a compatible preservative after field drilling or cutoff in accordance with AWPA M4. Charges must consist of pieces of the same species that are similar in form, size, moisture content, and receptivity of treatment. The pieces in the charge must be separated to ensure contact of treating medium with surfaces. Test to determine the retention of the preservatives. for Highway Construction Page 675 of 715 Include the following information in the certificate of treatment:
1.Name and location of the wood preserving company.
2.Customer identification.
3.Date of treatment and charge number.
4.Type of chemical used and the amount of retention.
5.Treating process and identification of the specifications used.
6.Description of material that was treated.
7.Signature of a responsible plant official. Chemically treat timber and lumber to be used in aquatic environments using BMPs. The producer of the chemically treated products must supply a written certification the BMPs were used, including a description and appropriate documentation of the BMPs used. Include this i nformation with or on the certificate of treatment record. Pressure treat s ign posts and fence posts with ammoniacal copper zinc arsenate (ACZA), chromated copper arsenate type C (CCA -C), copper naphthenate, or pentachlorophenol in accordance with AWPA standards, but ensure the minimum preservative retention in the wood meets the AWPA standards. Provide pressure treated guardrail post and blockouts with ACZA, chromated copper arsenate (CCA), copper naphthenate or pentachlorophenol in accordance with AWPA P5, P8, P9, and C4, but ensure the minimum preservative retention in the wood as determined by AWPA standards. for Highway Construction Page 676 of 71 5 SECTION 71 1 – ROADSIDE IMPROVEMENT MATERIAL
711.01 to 711.03. Reserved .
711.04 Riprap .
Material for riprap consists of natural or quarry stones, that are durable, angular, sound, hard, without seams and other structural defects, resistant to weathering and water action, and meet the testing requirements of either set of criteria in Table 711.04-1 A or Ta ble 711.04 -1B. Table 711.04-1A – Rip Rap Quality Testing Criteria for Approved Aggregate Sources Property Test Method Requirement Idaho Degradation Idaho IT 15 8% Max Loss Los Angeles Abrasion AASHTO T 96 40% Maximum Ethylene Glycol Idaho I T 116 90% Minimum Retained Table 711.04 -1B – Rip Rap Quality Testing Criteria for All Other Sources Property Test Method Requirement Apparent Specific Gravity AASHTO T 85 2.5 Min imum Absorption AASHTO T 85 4% Maximum Coarse Durability Index AASHTO T 210 52 Minimum
Source: Idaho Standard Specifications for Highway Construction, 2023 Edition. Pages 708–711 of 768.