57 WOOD AND PLASTIC LUMBER STRUCTURES
57-1 General
57-1.01 General
57-1.01A Summary
Section 57 -1 includes general specifications for constructing wood and plastic lumber structures.
57-1.01B Definitions
hardware : Bolts with necessary nuts and washers, timber connectors, drift pins, dowels, nails, screws, spikes, wire rope for wrapping, lag screws, and other metal fastenings. structural metal : Structural shapes, eyebars, ca stings, rods with necessary nuts and washers, metal shoes, and plates, but not including hardware.
57-1.01C Submittals
Reserved
57-1.01D Quality Assurance
Reserved
57-1.02 Materials
57-1.02A General
Deliver, store, and handle timber and lumber as follo ws:
1.Store in piles at the job site unless it is to be placed in the structure immediately .
2.Stack neatly on dunnage above ground so that it can be readily inspected .
3.Store and handle such that injury and breakage are avoided .
4.Protect from the su n to prevent warping .
57-1.02B Structural Metal
Structural metal must comply with section 75 -3. Hot-dip galvanize structural metal under section 75 -1.02B.
57-1.02C Hardware
Hardware must comply with section 75. Except for malleable iron washers, hot -dip galvanize hardware under section 75 -1.02B. Bolts and nuts must comply with ASTM A307. Machine bolt heads and nuts must be regular square series and threads must be coarse thread series, Class 2 tolerance, all complying with ANSI Standard. Washers must be cast iron ogee, malleable iron, plate, or cut washers. Nails must be common wire nails. Wire rope must be commercial -quality galvanized steel wire rope. Splices and end connections of wire rope must be made with metal clips.
57-1.03 Construction
Not Us ed
57-1.04 Payment
For a bid item with a MFBM measurement unit, the payment quantity is the volume determined from (1) nominal widths and thicknesses and (2) lengths shown. SECTION 57 WOOD AND PLASTIC LUMBER STRUCTURES
57-2 Wood Structures
57-2.01 General
57-2.01A General
57-2.01A(1) Summary
Section 57 -2 includes specifications for constructing wood structures .
57-2.01A(2) Definitions
Reserved
57-2.01A(3) Submittals
Submit a certificate of compliance for timber and lumber stati ng the species of the material to be shipped and including a certified grading report. If timber is treated, include a certified treating report. Submit a certificate of compliance for glued laminated timbers and glued laminated decking.
57-2.01A(4) Quali ty Assurance
Treated and untreated timber and lumber must comply with the grading specifications when delivered to the job site.
57-2.01B Materials
57-2.01B(1) General
Grease used to fill bolt holes must be recommended by the manufacturer for corrosion p rotection and must not melt or run at a temperature of 150 degrees F.
57-2.01B(2) Structural Timber and Lumber
Structural timber and lumber must be one of the species shown in the following table: Type Species Douglas fir Pseudotsuga menziesii Hem -Fir Abies magnifica, Abies grandis, Abies procera, Abies amabillis, Abies concolor, Tsuga heterophylla Redwood Sequoia sempervirens Southern yellow pine One of the species recognized by the Southern Pine Inspection Bureau Structural timber and lumber must be inspected and grade marked under the rules and specifications shown in the following table: Timber and Lu mber Grading Type Rules/specifications and publisher Douglas fir and Hem -Fir Standard No. 17 Grading Rules for West Coast Lumber published by West Coast Lumber Inspection Bureau, or Western Lumber Grading Rules published by Western Wood Products Association Redwood Standard Specifications for Grades of California Redwood Lumber published by Redwood Inspection Service Southern yellow pine Standard Grading Rules for Southern Pine Lumber published by Southern Pine Inspection Bureau Stress -graded lumber must comply with the following:
1.Wood must be sound and free from decay.
2.Green timber must be protected from uneven seasoning during transit.
3.Douglas fir must be end coated with a protective coating during manufacturing to reta rd checking. For all stress grades, the sizes described for timber and lumber are nominal sizes under American Softwood Lumber Standard , PS 20, published by NIST. SECTION 57 WOOD AND PLASTIC LUMBER STRUCTURES Plywood must be 3/4 -inch-thick Grade BC Douglas fir plywood manufactured with adhesives for wet use and must be preservative treated. Each glued laminated timber or decking unit must bear the American Institute of Timber Construction quality mark. Glued laminated timbers must be architectural grade with glue for wet use and saw -textured exposed surfaces. Glued laminated timbers must comply with ANSI/AITC A190.1 and AITC 117, published by the American Institute of Timber Construction. Glued laminated decking units must be:
1.Douglas fir, white pine, or Hem -Fir
2.Kiln-dried solid stock lumber
3.Factory laminated using adhesive for wet use
4.At least 3 plies thick, with tongue and groove edges
5.At least 5.5 inches in width and thickness The surface of glued laminated decking units at exposed faces must be saw textured.
57-2.01B(3) Preservative Treatment
Where preservative treatment is specified, treat timber, lumber, and piling after millwork is completed. Preser vatives, treatment, and treatment results must comply with AWPA Standards U1 and T1 and the specified AWPA Use Category. If a Use Category is not specified, the preservative treatment must comply with AWPA U1, Use Category UC4B. The treating plant must imp rint legible symbols in the ends of all treated timber and lumber . The symbols must indicate the name of the treating company and the type and year of treatment under AWPA Standards M1 and M6. Timber and lumber treated with waterborne preservatives m ust be dried after treatment and have no visual evidence of preservative on the surface. For treated wood that is to be painted, use a waterborne wood preservative. Manually applied wood preservative must compl y with AWPA Standard M4.
57-2.01C Construction
57-2.01C(1) General
Reserved
57-2.01C(2) Framing
Timber and lumber must be accurately cut and framed to a close fit and must have even bearing over the entire contact surface. Do not use shimming in making joints. Bore fasten er holes as shown in the following table: SECTION 57 WOOD AND PLASTIC LUMBER STRUCTURES Fastener Bore Holes Fastener type Member type Boring requirement Drift pin or dowel Untreated timber Hole diameter a minimum of 1/16 inch less than the pin or dowel diameter Treated timber Hole diameter the same as the pin or dowel diameter Bolt All cases Hole diameter a maximum of 1/16 inch larger than the bolt diameter Lag screw All cases Bit diameter a maximum of the root diameter of the lag screw thread Boat or wire spike Small member, if necessary to prevent splitting Bit diameter the same as the spike diameter or the smallest dimension of the spike Fit each bolt 5/8 inch or less in diameter with a cut washer. Fit each bolt or lag screw over 5/8 inch in diameter with a cast or malleable iron washer. Framed bents must comply with the following:
1.Mud sills must be firmly and evenly bedded in solid material.
2.Sills must have full, even bearing on the pedestals, mud sills, or piles.
3.Posts must be framed true and must have full bearing on pedestals, sills, and caps. Align bents before placing bracing . Provide a minimum of 8 inches between the outside bolt and the end of the brace. For bridge deck strin gers, place the better edge down. After placing stringers, the tops of the stringers must not vary from a plane more than will allow bearing of the floor on all the stringers. Wheel guards and railings must be accurately framed and aligned.
57-2.01C(3) Treated Timber
57-2.01C(3)(a) General
Chromated copper arsenate must not be used for handrails or other applications with possible direct exposure to the public. Do not remove bolts and hardware using flame -type or air -arc cutting equipment. Predrill for bridge spikes within 1 foot of the ends of existing timbers and new planking. Predril l elsewhere if necessary to avoid splitting the timber or bending the spikes. If authorized, you may relocate holes for new bolts and drift pins to avoid conflicts with existing hardware embedded in existing wood. For lumber treated with ammoniacal copper zinc arsenate, alkaline copper quaternary ammonium compound , or copper azole:
1.Fill bolt holes with grease before inserting bolts
2.Use nylon spacers, polyethylene tape, or other authorized corrosion -resistant barrier on surfaces of hardware that will b e in contact with treated wood
57-2.01C(3)(b) Manual Treatment
Do not manually apply preservative to unprotected wood in wet or damp weather or to wood with a moisture content exceeding 25 percent or with free surface moisture. If manually applying prese rvative, use suitable brushes for exposed surfaces, use swabs for holes, or use other means that result in adequate coverage. If treated timber is framed, cut, or bored after treatment, thoroughly swab each cut, dap, or hole with 2 applications of a preser vative as specified in AWPA Standard M4. SECTION 57 WOOD AND PLASTIC LUMBER STRUCTURES Manually treat the following items with 2 applications of wood preservative:
1.Portions of rail posts to be embedded in earth or concrete
2.Faces of timber bulkheads to be in contact with earth except those of tre ated Douglas fir
57-2.01C(3)(c) Handling
Handle and care for pressure -treated wood materials under AWPA Standard M4. Handle treated timber with rope slings. Do not use cant hooks, peaveys, or other sharp instruments to handle treated timber.
57-2.01C(4) Painting
For painted timber and lumber , comply with section 78 -4.02. Paint the following items with 1 application of latex -base wood primer and 2 applications of white exterior latex -base d paint:
1.Rails
2.Portions of rail posts not embedded in earth or concrete
3.Wheel guards or timber curbs except the bottom faces over an earth surface
4.Exposed faces of posts
57-2.01D Payment
Not Used
57-2.02 Timber Lagging
57-2.02A General
Section 57 -2.02 includes sp ecifications for installing timber lagging .
57-2.02B Materials
Timber members must be (1) preservative -treated Douglas fir and (2) full sawn to the dimensions shown. HDPE shims must be commercial quality.
57-2.02C Construction
Install lagging members 4 inches thick or less with a 3/8 -inch gap between members. Install lagging members greater than 4 inches thick with a 1/2 -inch gap between members.
57-2.02D Payment
Not Used
57-2.03 Timber Catwalk
57-2.03A Gen eral
Section 57 -2.03 includes specifications for constructing timber catwalks . A timber catwalk consists of a walkway of two 3 -by 12 -inch planks bolted to steel supports and a cable handrail, if shown.
57-2.03B Materials
57-2.03B(1) General
Reserved
57-2.03B(2) Timber Planks
The timber planks must be untreated Douglas fir Dense no. 1, rough sawn on top, optional surfaced on bottom.
57-2.03B(3) Cable Handrail
The cable for the cable handrail must be wire rope with a minimum diameter of 1/2 inch and a minimum breaking strength of 7,500 lb. The wire rope must be furnished with Class A weight zinc -coated wire under ASTM A603. SECTION 57 WOOD AND PLASTIC LUMBER STRUCTURES The turnbuckles, U -bolts, and thimbles must be commercial quality. The turnbuckles must be steel pipe type or drop forged steel and must have jaw or eye ends. The turnbuckles and U -bolts must have a minimum breaking strength of 7,500 lb. The cable clamps and other required fittings must be commercial -quality steel, malleable iron, or wrought iron. Galvanize hardware, turnbuckles, U -bolts, cable clamps, and other fittings under section 75 -1.02B.
57-2.03C Construction
Tension the handrail cables to provide taut railings between supports. Steel surfaces to be covered by timber must be painted the full nu mber of applications specified before placing timber. Painting of timber planks is not required.
57-2.03D Payment
Not Used
57-2.04 Abutment Lumber Blocking
Reserved
57-2.05 Timber Retaining Walls
Reserved
57-2.06 57-2.10 Reserved
57-3 Plastic Lumber S Tructures
57-3.01 General
57-3.01A Summary
Section 57 -3 includes specifications for constructing plastic lumber structures .
57-3.01B Definitions
postconsumer waste: Finished material, n ot including manufacturing waste, that has completed its life cycle as a consumer item and would have been disposed of as a solid waste. production lot of plastic lumber: Quantity of 100 cu yd or less that is ready for shipment to the job site and is of th e same type, manufactured by the same method, and made of the same material. recycled product: Material, good, or supply, of which at least 50 percent of its total mass consists of secondary waste and at least 10 percent of its total mass consists of postc onsumer waste. secondary waste: Finished products or fragments of finished products of a manufacturing process, including postconsumer waste but not including excess virgin resources of the manufacturing process.
57-3.01C Submittals
57-3.01C(1) General
Submit the following product dat a:
1.Manufacturer's material test reports
2.Manufacturer's performance data
3.SDSs
4.2 copies of the printed literature for the product Submit a certificate of compliance for each shipment of plastic lumber. The certificate must be accompanied by a la boratory test report. Submit test samples for void testing. Submit results of stiffness tests. SECTION 57 WOOD AND PLASTIC LUMBER STRUCTURES
57-3.01C(2) Shop Drawings
Submit 5 copies of shop drawings for the plastic lumber for initial review. After review, submit from 6 to 12 copies, as requested, fo r authorization and use during construction. Shop drawings must show:
1.Details for component layout and connections
2.Sequence of shop and field assembly
3.Installation procedures
57-3.01D Quality Assurance
57-3.01D(1) General
Reserved
57-3.01D(2) Quality Control
57-3.01D(2)(a) General
Start a new production lot if any production parameter changes before the maximum production lot size is reached.
57-3.01D(2)(b) Stiffness Test
Before shipment to the job site, perform stiffness tests for the plastic lumber in the presence of the Engineer at an authorized laboratory. Notify the Engineer at least 15 days before conducting the tests. The Engineer randomly selects 2 test samples from each production lot for stiffness testing. Determine the stiffne ss and the yield stress in bending under ASTM D790, except the test samples must have a minimum length of 13 feet and tests must be performed on a 12 -foot span length at a crosshead motion of 0.25 inch per minute. Calculate the stiffness using the secant m odulus at the flexural strain of 0.010 inch per inch. If the stiffness or the yield stress in bending of either of the 2 test samples does not comply with section
57-3 02A, perform a retest on 2 additional test samples selected by the Engineer. If the stif fness or the
yield stress in bending of either of the 2 additional test samples does not comply with section 57 -3.02A in the retest, the entire production lot of plastic lumber represented by the test samples is rejected.
57-3.01D(3) Department Acceptance
57-3.01D(3)(a) General
The Engineer selects 2 test samples of each size from each production lot of plastic lumber delivered to the job site for void testing.
57-3.01D(3)(b) Void Testing
57-3.01D(3)(b)(i) General
Before use in the work, the plastic lum ber must be tested for both exterior and interior voids. Allow 15 days for void testing.
57-3.01D(3)(b)(ii) Exterior Void Test
The Engineer examines the test samples for exterior voids. If the exterior voids of either of the 2 test samples do not comply w ith section 57 -3.02A, the Engineer selects 2 additional test samples and performs a retest. If the exterior voids of either of the 2 additional test samples do not comply with section 57 -3.02A in the retest, the entire production lot of plastic lumber represented by the test samples is rejected.
57-3.01D(3)(b)(iii) Interior Void Test
After acceptance under the exterior void test, cut the test samples into 1 -foot-long segments. The Engineer examines the cut sections for interior voids. If the interior voids of a cut section of either of the 2 test samples do not comply with section 57 -3.02A, the Engineer selects 2 additional test samples and performs a retest. If the interior voids of a cut section SECTION 57 WOOD AND PLASTIC LUMBER STRUCTURES of either of the 2 additional test samples do not comply wit h section 57 -3.02A in the retest, the entire production lot of plastic lumber represented by the test samples is rejected.
57-3.02 Materials
57-3.02A General
Plastic lumber must:
1.Be produced continuously and homogeneously without joints
2.Be straight and true and free from twist, curvature, bulging, or other deformations
3.Have a smooth outer layer with no visible voids
4.Not vary from the dimensions shown by more than 1/2 inch for cross -sectional dimensions or 1 inch for the length
5.Have total re sistance to marine borers and dry rot
6.Not swell, shrink, or crack
7.Comply with the requirements shown in the following table: Quality characteristic Test method Requirement Density (kg/m3, min) ASTM D792, Test Method A Skin: 880 Core: 680 Water absorption (weight increase, %, max) ASTM D570 1.0 at 2 hours; 3.0 at 24 hours Brittleness, (at -40 °C) ASTM D746 Skin: No break Hardness ASTM D2240, Type D Skin: 45 –75 UV deterioration (hardness change, percent after 500 hours of exposure, max) ASTM D4587a ASTM D2240, Type D Skin: 10 Abrasion ASTM D4060: Cycles: 10,000 Wheel: CS17 Load: 1 kg Skin: Weight loss: < 500 mg Wear index: 2.5 –3.0 Chemical resistance (weight increase, %) ASTM D543: Practice A, Procedure 1 Sea water: < 1.5 Gasoline: < 7.5 No. 2 diesel: < 6.0 Coefficient of thermal expansion (per degree C, max) ASTM D696 0.00009 Ignition temperature ( °C) ASTM D1929 > 340 aASTM D4329 using UVA 340 bulbs operating at a UV intensity of 0.77 W/m2/nm measured at 340 nm. The exposure cycle must be 4 hours of ultraviolet (UV) exposure at 60 °C and 4 hours of condensate (CON) exposure at 40 °C. Stiffness and yield stress in bending of plastic lumber must have at least the values shown in the followi ng table: Cross section size (inches) Stiffness EI (kip-sq ft) Yield stress in bending (psi) 8 x 10 932 4,650 8 x 12 883 3,775 10 x 10 1,764 3,900 10 x 12 1,830 3,625 12 x 12 2,892 3,050 NOTE: These values are for the weak axis of rectangular sections. For the exterior voids at each exposed end of plastic lumber:
1.Maximum dimension of any void must not exceed 1 inch
2.Total number of voids with a maximum dimension greater than 1/4 inch must not exceed 4 For the interior voids in the cut sections of each segment of plastic lumber: SECTION 57 WOOD AND PLASTIC LUMBER STRUCTURES
1.Maximum dimension of any void in a cut section must not exceed 1/2 inch
2.Total area of voids in a cut section must not exceed 5 percent of the total cross -sectional area Permanently mark each piece of plastic lumber with the manufacturer's name. Ship and store plastic lumber in a way that minimizes scratching or damage to the outer surfaces.
57-3.02B Reinforced Recycled Plastic Lumber
Reinforced RPL must consist of recycled plastic reinforced with fiberglass reinforcing bar elements, fiberglass filaments, or a combination of both. Reinforced RPL must be a recycled product. Fabricate reinforced RPL from one or more of the following thermoplastics:
1.High-density polyethylene
2.Medium -density polyethylene
3.Low-density polyethylene
4.High-density polypropylene Reinforced RPL must have a dense outer skin at least 3/16 -inch-thick surrounding a less dense core. The plastic for the outer skin must be mix ed with colorants to match color no. 37030 or 30097 of AMS -STD- 595 and must contain a UV inhibitor and antioxidants. Fiberglass reinforcing bar elements must comply with the requirements shown in the following table: Quality characteristic Test method Requ irement Flexural strength (psi, min) ASTM D790 70,000 Compression modulus (psi, min) ASTM D695 40,000 Tensile strength (psi, min) ASTM D638 70,000 Fiberglass filaments must comply with the requirements shown in the following table: Quality characteristic Test method Requirement Density (kg/m3) ASTM D792 2,560 –2,592 Mechanical, single filament tensile strength (MPa) ASTM D3822 3,450 –3,790 Tensile modulus of elasticity (MPa) ASTM D3822 69–72 All reinforced RPL must contain the same type of reinforcement.
57-3.02C Composite Plastic Lumber
CPL may be substituted for reinforced RPL. Fabricate the shell for CPL from polyester or epoxy resin reinforced with E -glass and mixed with colorants, UV inhibitors, and antioxidants. The CPL coating must match color no. 37030 or 30097 of AMS -STD-595. The core material for CPL must be lightweight aggregate polymer concrete. CPL must comply with the physical quality characteristics specified for reinforced RPL and the requirements shown in the following table: SECTION 57 WOOD AND PLASTIC LUMBER STRUCTURES Quality characteristic Test method Requirement Density of concrete core (kg/m3 , min) ASTM D792 1,762 28-day compressive strength of concrete core (psi, min) ASTM C579 5,000 Structural strength of shell: Tensile strength, tensile modulus ( % loss) Flexural strength, flexural modulus ( % loss) ASTM D638 ASTM D790 Less than 10 after UV deterioration test specified for plastic lumber Dry film thickness of coating (mils, min) -- 15 Color change of coating ASTM D4587, Test Cycle 2 No visible color change when tested for 800 hours Initial adhesion of coating (psi, min) ASTM D4541, Test Method D, E, or F and Protocol 2 150 Decrease in initial adhesion of coating, decrease ( %) ASTM D4541, Test Method D, E, or F and Protocol 2 ASTM D1183, Test Condition Da No more than 10 following 2 exposure cycles aUse a low temperature phase at 4 ± 5 °F and high temperature phase at 140 ± 5 °F. Seal the cut ends of CPL with a cap securely held in place with an adhesive recommended by the manufacturer. The adhesive must show no more than a 10 percent decrease in strength when tested under ASTM D3164 following 2 cycles of exposure under ASTM D1183, Test Condition D, with a low temperature phase of -16 ± 3 degrees C and a high temperature phase of 60 ± 3 degrees C.
57-3.02D Unreinforced Recycled Plastic Lumber
Unreinforced RPL may be substituted for reinf orced RPL for chocks, filler blocks, and other nonstructural members shown. Unreinforced RPL must comply with the specifications for reinforced RPL, except fiberglass reinforcement is not required and stiffness tests do not apply.
57-3.03 Construction
Install plastic lumber under the manufacturer's instructions. Cut, bevel, drill, counterbore, and otherwise fabricate plastic lumber under the manufacturer's instructions. Fabricate lumber in the manufacturer's plant to the greatest extent possible. Holes for bolts in plastic lumber must be bored 1/8 inch larger in diameter than the bolt to be placed. Holes for lag screws must be bored to a diameter under the manufacturer's instructions. Recess bolts and lag screw heads 1/2 inch from the surface of the face of plastic lumber fenders. Coat holes drilled through CPL members with a concrete sealant approved by the CPL manufacturer. Plastic lumber elements that are split, broken, warped, or otherwise damaged are rejected.
57-3.04 Payment
Not Used
57-3.05 57-3.10 Reserved
Source: California Standard Specifications, 2024 Edition. Pages 887–896 of 1,372.