SPECIFICATIONS FOR BRIDGE CONSTRUCTION SECTION 23 DIMENSIONAL STRUCTURAL LUMBER AND PILING General Standards...

Transcription

1 SPECIFICATIONS FOR BRIDGE CONSTRUCTION SECTION 23 DIMENSIONAL STRUCTURAL LUMBER AND PILING TABLE OF CONTENTS 23.1 General Standards Material Specification Planking (S1S1E Strip Deck ) Sheeting, Retainers, Nailers and S1S1E Subdeck Rough Caps Framed Subcaps Wheelguards Rough Stringers Struts and Handrails Posts S1S1E Cleats Railing Piling Air Seasoning Kiln Drying Incising Creosote Treatment Chromate Copper Arsenate (CCA) Treatment Handling, Storage and Care of Wood Inspection Acceptance

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3 23.1 General This specification is for the supply and treatment of dimensional structural lumber and round timber piles. Dimensions are metric, imperial dimensions are shown in parentheses Standards The grading shall be as per National Lumber Grading Authority (NLGA) Standard Grading Rules for Canadian Lumber and CAN/CSA O Softwood Lumber. The round wood piles shall be as per CAN3-056-M79. The treatment shall conform to CSA Wood Preservation, CSA Preservative Treatment of Lumber, Bridge Ties, and Mine Ties by Pressure Process; CSA Preservative Treatment of Piles by Pressure Process and American Wood Preservers Association (AWPA) Standard C1, C2, M4 and Supplementary Requirements to M Material Specification All material shall be full sawn unless otherwise noted in the Special Provisions Planking (S1S1E Strip Deck) The material shall be Species Group HEM-FIR conforming to the stress grade No. 1 Structural Joists and Planks (NLGA paragraph 124 b), allowing a maximum of 20% of the Board Measure (BM) to conform to the stress grade No. 2 of each size length supplied Sheeting, Retainers, Nailers and S1S1E Subdeck The material shall be Coast Douglas Fir or Pacific Coast Hemlock species conforming to the stress grade No. 1 Structural Joists and Planks (NLGA paragraph 124 b), allowing a maximum of 15% of the Board Measure (BM) to conform to the stress grade No. 2 Structural Joists and Planks, (NLGA paragraph 124 c) Rough Caps The material shall be Coast Douglas Fir species, conforming to the stress grade Select Structural Posts and Timbers (NLGA paragraph 131 a) Framed Subcaps The material shall be Coast Douglas Fir species, conforming to the stress grade Select Structural Posts and Timbers (NLGA paragraph 131 a). The 305 mm x 355 mm (12 x 14 ) cap has a length of 4.6 m (15 ). From the center of the 4.6 m (15 ) length in both directions along the length, for the 355 mm (14 ) depth, the cap is cut on a continuous 2% slope which results in an end depth of 310 mm (12¼ ). The 305 mm (12 ) width remains constant. 23-1

4 Wheelguards The material shall be Coast Douglas Fir or Pacific Coast Hemlock species conforming to the stress grade No. 1 Structural Beams and Stringers (NLGA paragraph 130 b), allowing a maximum of 15% of the BM to conform to the stress grade "No. 2 Structural Beams and Stringers" (NLGA paragraph 130 c) Rough Stringers The material shall be Coast Douglas Fir species conforming to the stress grade Select Structural Beams and Stringers (NLGA paragraph 130 a), allowing a maximum of 10% of the BM to conform to the stress grade No. 1 Structural Beams and Stringers (NLGA paragraph 130 b) Struts and Handrails Posts The material shall be Coast Douglas Fir or Pacific Coast Hemlock species, conforming to the stress grade Select Structural Post and Timbers (NLGA paragraph 131 a) allowing a maximum of 15% of the BM conforming to the stress grade "No. 1 Structural Post and Timbers" (NLGA paragraph 131 b) S1S1E Cleats The material shall be Coast Douglas Fir or Pacific Coast Hemlock species, conforming to the stress grade No. 2 Structural Joists and Planks (NLGA paragraph 124 c) Railing The material shall be S4S and is to be of the Coast Douglas Fir or Pacific Coast Hemlock species conforming to the stress grade No. 1 Structural Joists and Planks (NLGA paragraph 124 b) Piling All piles shall be cut from sound trees of Douglas Fir or Pine. The piles shall be clean peeled soon after being felled. All bark shall be thoroughly removed and no pile shall be considered thoroughly peeled unless all the rough bark and all the inner bark have been removed. When a portion of pile is rough and convoluted, the inner bark may remain in the depressions, provided that any such depression is not more than 20 mm (¾ ) in width and 205 mm (8 ) in length. (a) Dimensions Unless otherwise specified, the minimum diameter after the outer and inner bark has been removed and after seasoning, will be as follows: SIZES OF TIMBER PILES Length (m) Tip Diameter Butt Diameter Up to 6.1 (20 ) 230 (9 ) 305 (12 ) 6.2 to 12.2 (20.25 to 40 ) 205 (8 ) 305 (12 ) 12.3 to 18.3 (40.25 to 60 ) 180 (7 ) 330 (13 ) 23-2

5 However, a pile may be 12 mm (½ ) smaller in either or both tip and butt diameters in one axis provided that the minimum circumferences are as follows: Diameter Circumference 180 (7 ) 535 (21 ) 205 (8 ) 610 (24 ) 230 (9 ) 685 (27 ) 305 (12 ) 940 (37 ) 330 (13 ) 1015 (40 ) The maximum butt diameter shall not exceed 405 mm (16 ). (b) Sapwood The minimum thickness of the sapwood shall be 12 mm (½ ) as measured on the small end of the pile. However, no pile will be rejected where the thickness of the sapwood falls below 12 mm (½ ), but not lower than 10 mm (⅜ ) for a distance of 150 mm (6 ) as measured around the circumference, provided it is of the minimum thickness around the balance of the circumference. (c) Knots Single knots will not be considered a defect unless they are loose or show signs of decay. A knot cluster that is the grouping of two or more knots together as a unit, with the fibres of the wood deflected around the entire unit, shall be reason for rejection of the pile. All knots shall be trimmed close to the body of the pile. (d) Straightness A line drawn from the centre of the butt and to the centre of the tip shall lie within the body of the pile. Piles shall be free from short bends in which the distance from the centre of the pile to a line stretched from the centre of the pile above the bend to the centre of the pile below the bend exceeds 4 per cent of the length of the bend, or 65 mm (2½ ). (e) Pitch Streaks Pitch streaks that extend through the length of the pile shall be cause for rejection Air Seasoning Air seasoning shall be as per Clause 1.7 of CSA 080.M1-97 (Guide for Purchasers and Specifiers of Treated Wood). Moisture content shall not be more than 19% prior to treatment Kiln Drying The material may be kiln dried in lieu of air seasoning as per Clause 1.10 of CSA 080.M1-97 (Guide for Purchasers and Specifiers of Treated Wood). The moisture content shall not exceed 19% prior to treatment. The supplier shall ensure that the material is stacked to allow maximum ventilation between lumber and reduce any warping or checking. 23-3

6 23.6 Incising The material shall be incised on all four sides and all around for round piles prior to treatment by a method that will provide at least the minimum penetration specified without any damage and with the least loss of strength Creosote Treatment (1) The material seasoned and incised as per Clauses 4.0 or 5.0 and 6.0 shall be pressure treated using 100% creosote treatment. (2) Treatment shall conform to CSA Preservative Treatment of Lumber, Bridge Ties, and Mine Ties by Pressure Process and AWPA Standard C1 and C2. The retention shall be 96 kg/m 3 (6 lb/ft 3 ) by gauge, 128 kg/m 3 (8 lb/ft 3 ) by assay Chromate Copper Arsenate (CCA) Treatment (1) When noted in the Special Provisions the planking material (strip deck) and guardrail posts seasoned and incised as per Clauses 4.0 or 5.0 and 6.0 shall be pressure treated using a waterborne preservative Chromate Copper Arsenate (CCA). (2) Treatment shall conform to CSA Preservative Treatment of Lumber, Bridge Ties, and Mine Ties by Pressure Process and AWPA Standard C1 and C2. (3) The retention and penetration shall be 6.4 kg/m 3 (0.4 lb/ft 3 ) and 10 mm (0.4 ), respectively by assay Handling, Storage and Care of Wood Wood shall be kept free of dirt and shall be stored in a location which will not create an excessive increase in temperature (green house effect) resulting in rapid drying of the material. Wood shall be stored in a manner, which will prevent ponding or trapping of excess moisture between surfaces where it cannot dry readily. Where oil treatment is used, the wood shall be given three coats of creosote oil to repair all cuts, abrasions and holes made after the pressure preservative treatment. Each coat shall be allowed to dry before the next coat is applied. Repair of cuts, abrasions and holes in material treated with water-borne preservative shall conform to CSA 080 and AWPA Inspection The supplier shall provide for inspection of the material by an independent inspector who is qualified and has a minimum of 10 years of experience for this type of inspection. All material shall be inspected prior to and after the treatment. All material shall be stamped by the inspector 23-4

7 identifying the inspection date and that the material meets or exceeds the required specifications. The stamp shall be placed at the end of each member in a location that is clearly visible even when the material is in a large stockpile. A written report from the inspector along with his experience and qualifications indicating the material meets the specifications with a Certificate of Compliance shall be forwarded to the Consultant and Owner Acceptance (1) All materials shall be subject to inspection by the Consultant/Owner prior to usage. (2) Where S1S1E or S4S Size is specified the material shall be not more than 6 mm (¼") scant per side. (3) When for example 15% No. 1 or 15% No. 2 grade is allowed, this shall mean 85% must be the specified grade and not more than 5% of the 15% is below No. 1 or No. 2 grade or there will be grounds for reinspection. 23-5