502.1 General Description
This work consists of constructing timber bridges and other timber structures complete in place.
502.1.01 Definitions
General Provisions 101 through 150.
502.1.02 Related References
A. Standard Specifications Section 501—Steel Structures Section 520—Piling Section 645—Repair of Galvanized Coatings Section 852—Miscellaneous Steel Materials B. Referenced Documents AWPA Standard M4, Standard for the Care of Preservative Treated Wood Products
502.1.03 Submittals
General Provisions 101 through 150.
502.2 Materials
All materials shall meet the requirements of the following Specifications: Material* Section Lumber and Timber 860 Piling and Round Timber 861 Preservative Treatment of Timber Products 863 Miscellaneous Metals 858 Structural Steel 851 Plain Cotton Duck 881 Miscellaneous Steel Materials 852 Paint 870 *Insofar as practicable, all cutting, framing, and boring of treated timber shall be done before treatment. A. Miscellaneous Hardware Galvanize the following items according to Subsection 852.2.04.B.3, Galvanizing: • Bolts • Nuts • Washers • All hardware including (but not limited to) special couplings, dowels, and spikes Repair damaged galvanized coatings according to Section 645. Nails may be black or galvanized. B. Structural Purposes and Grades Lumber and timber meeting the requirements given in Table 1 of Section 860, Lumber and Timber, shall be used for the structural purposes shown therein.
502.2.01 Delivery, Storage, and Handling
A. Handling Timber Handle timber carefully without dropping it, breaking the outer fibers, bruising it, or piercing it with tools. Handle timber with non-metallic slings. B. Storing Materials Place all stored material in well-drained locations and keep these locations free from weeds and rubbish. Comply with the following material-specific storage guidelines: 1. Untreated Timber and Piling Store untreated materials as follows: a. Open stack the materials at least 12 in (300 mm) above the ground. b. Pile the materials so water can run off them to prevent warping. c. Protect the materials with durable waterproof covering approved by the Engineer. 2. Treated Timber and Piling Close stack treated materials at least 12 in (300 mm) above the ground and pile them to prevent warping. 3. Timber After Fabrication Store this timber so the members do not change dimensions before they are assembled. 4. Hardware and Miscellaneous Metal Place metal material in covered storage and protect it from rust and other damage.
502.3 Construction Requirements
General Provisions 101 through 150.
502.3.01 Personnel
General Provisions 101 through 150.
502.3.02 Equipment
General Provisions 101 through 150.
502.3.03 Preparation
General Provisions 101 through 150.
502.3.04 Fabrication
General Provisions 101 through 150.
502.3.05 Construction
A. Making Field Repairs and Applying Treatments and Coatings Make field repairs and apply treatments and coatings as follows: 1. Repair and Apply Treatments to Treated Timber Carefully trim cuts and abrasions in creosoted timber or piles and treat them with either of the following: • Two hot applications of 60 percent creosote oil mixed with 40 percent roofing pitch • Two thorough brush coats of hot creosote oil followed by a covering of hot roofing pitch For field treatment of other preservatives, see AWPA Standard M4 entitled, “Standard for the Care of Preservative Treated Wood Products.” a. Bolt Holes Treat bolt holes with creosote oil using an approved, manufacturer-recommended, pressure bolt hole treater. After the treatment, plug unfilled holes with creosoted plugs. b. Temporary Holes When the approved use of temporary forms or braces results in nail or spike holes in treated timbers or piles, fill these holes by driving galvanized nails or spikes flush with the surface or by plugging as specified in Subsection 502.3.05.A.1.a, Bolt Holes. c. Countersunk Holes Treat these holes with hot creosote oil before placing the bolts. After placing the bolts, fill the holes with hot roofing pitch. 2. Apply Treatment to Pile Heads See Subsection 520.3.05.J, Repair and Treat Timber Piling, step 5. B. Framing Cut and frame lumber and timber to a close fit so the joints will have an even bearing over the entire contact surface. The Department does not permit shimming or open joints. Match-mark timbers requiring an exact fit. 1. Meet Workmanship Requirements Ensure that workmanship meets the following standards: a. Nails and Spikes Drive nails and spikes hard enough to set their heads flush with wooden surfaces. Replace bent nails or spikes. The Department considers deep hammer marks on wooden surfaces poor workmanship. The Department may reject the work with these characteristics. b. Steel Plates and Structural Shapes Workmanship on steel plates and structural shapes shall meet the requirements of Section 501. 2. Drill Holes for Bolts, Dowels, Rods, and Lag Screws Drill holes with the following diameters to receive these hardware items Hardware Hole Diameter Round drift bolts and dowels 1/16 in (2 mm) smaller than the diameter of the hardware Square drift bolts and dowels Same as the smallest dimension of the hardware Machine bolts Same as the diameter of the hardware Rods 1/16 in (2 mm) larger than the diameter of the hardware Lag Screws No larger than the body of the screw at the base of the thread Countersink holes wherever smooth faces are required. 3. Use Bolts and Washers Use washers of the size and type specified on the Plans under bolt heads and nuts to prevent them from contacting the wood. After completely adjusting the nuts, do the following: a. Cut the excess length off of bolts projecting more than 1 in. (25 mm) beyond the nuts. b. Burr the bolt threads. c. Coat the bolt ends with galvanizing repair compound according to Section 645. C. Constructing Timber Substructures Construct the timber substructure as follows: 1. Drive the Pile Bents. See Section 520.3.05.E, Drive Piling. 2. Place the Caps. Place timber caps so the bearing on their supports is evenly secured and their ends are evenly aligned. Drift bolt the caps to piles and posts. 3. Bolt the Bracing. Bolt timber braces where they intersect with piles and posts. D. Constructing Timber Superstructures Construct the timber superstructure as follows: 1. Install Stringers. Install stringers using these guidelines: • Where stringers bear over the width of floor beams and caps, size the stringers to a uniform grade. • Ensure that lapped ends of treated stringers contact each other. • Neatly and accurately frame cross-bridging between stringers. • Securely toenail the cross bridging by driving at least two nails in each end. 2. Lay Single Plank Floors. Lay these floors using these guidelines: • Lay planks with the adjacent planks drawn together tightly. Lay the plank so the thickness of adjacent planks varies by no more than 1/16 in (2 mm). • Spike each plank to each joist or nailing strip using at least two spikes. The spike length shall be at least 3 in (75 mm) greater than the thickness of the planks. • Carefully grade the plank thickness. 3. Lay Laminated or Strip Floors. Lay these floors using these guidelines: • Dress strips to a uniform thickness of no more than 3 in. (75 mm) and to a uniform width when specified on the plans. • Place strips on the edge and at right angles to the roadway center line. • Spike each strip to the adjacent strip at 2 ft. (600 mm) intervals by staggering succeeding spike locations 8 in. (200 mm) from preceding locations. Ensure that the spike length is sufficient to pass through two strips and at least halfway into the third. • Toenail strips to the stringers with 20 d (4 mm) nails. Instead of toenailing, the Contractor may drive spikes vertically through the strip if they penetrate the stringer at least 3 in. (75 mm). 4. Frame and Erect Hub Guards and Railings. Accurately frame and erect hub guards, scupper blocks, joist blocks, and railings to true line and grade. Use these guidelines when erecting hub guards and railings: • Dress hub guards, scupper blocks, railings, and rail posts on all four sides. • Securely spike the scupper blocks in place. • Bolt the hub guards through the scupper blocks, floor planks, and, if required, through the outside joists or nailing pieces. • Lay hub guards in sections at least 12 ft. (3.7 m) long.
502.3.06 Quality Acceptance
General Provisions 101 through 150.
502.3.07 Contractor Warranty and Maintenance
General Provisions 101 through 150.
502.4 Measurement
A. Structural Metal Plates and structural shapes required on the Plans will be measured for payment as specified on the Plans only when set up as a Specified Pay Item. Measurement will then be made as provided in Subsection 501.4, Measurement, and the cost shall not be included in the Contract prices for lumber and timber. Otherwise, no separate measurement for payment will be made, and the cost shall be included in the Contract prices for lumber and timber. B. Lumber and Timber Lumber and timber will be measured per thousand feet (cubic meter) board measure (MBM). Quantities in the structure will be computed based upon nominal sizes and the actual length in place.
502.4.01 Limits
A. Timber Piling Timber piling shall be furnished, driven, and measured as a Pay Item under Section 520 unless otherwise specified. B. Splices No additional measurement will be made for splices except for overlaps shown on the Plans. C. Hardware No separate measurement for payment will be made for items such as the following: • U-bolts • V-bolts • Oval head bolts • Special couplings • Bolts • Nuts • Washers • Dowels • Nails • Spikes • Other hardware. The cost of these items shall be included in the Contract Unit Price bid for timber.
502.5 Payment
A. Structural Metal The quantity of structural metal (determined as described below in Subsection 502.4.A Structural Metal, will be paid at the Contract Price according to Subsection 501.5, Payment for Steel Structures. B. Lumber and Timber Lumber and timber will be paid for at the Contract Unit Price bid per thousand feet board measure (MBM) (cubic meter), complete in place and accepted. The payment will be full compensation for material, labor, and equipment necessary to complete the Work as shown on the Plans and as described in this Specification. Payment includes incidentals and all costs, both direct and indirect. Payment will be made under: Item No. 502 Bridge timber (untreated) Per MBM (cubic meter) Item No. 502 Bridge timber (treated) Per MBM (cubic meter)
502.5.01 Adjustments
General Provisions 101 through 150.
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