Method of Measurement 556.16 The quantity to be paid for under this item will be the number of linear feet of bridge railing of the several types, complete in place and accepted, measured along the line and grade of the railing from center to center of metal end posts. It will include all work constructed above the top of the curb and all fastenings and anchors required to attach the railing to the structure. It will include that portion of reinforcement steel for railing which extends into the curb. Lump sum measurement, if called for in the bid schedule, will be in accordance with subsection 109.01. Basis of Payment 556.17 When the bid schedule contains an estimated quantity for any of the pay items below, the quantity, determined as provided above, will be paid for at the contract price per pay unit or lump sum respectively, for each of the particular pay items listed below that is shown in the bid schedule, which price and payment will be full compensation for the work prescribed in this section. When the plans or special provisions provide for the construction of bridge railing for which the bid schedule contains no estimated quantity or lump sum under any one of the pay items below, such railing will be considered as an integral portion of the structure to which it is attached and will be paid for as provided under the applicable section covering the bridge construction. 557.01 Section 557.-TIMBER STRUCTURES Description This work shall consist of timber structures and the timber portions of composite structures, constructed in reasonably close conformity with the lines, grades, dimensions and designs shown on the plans or ordered in writing by the Engineer. 557.01 It will include the furnishing, preparing, erecting, and painting of structural timber of the stress values, sizes, and dimensions specified, treated or untreated as called for in the bid schedule. Also included will be any required yard lumber of the sizes and grades specified and all hardware, as shown on the plans or ordered by the Engineer. Materials 557.02 Materials shall meet the requirements of the following subsections: Structural Shapes, Rods, and Plates. All structural shapes, rods, and plates shall be of structural steel or wrought iron, as specified or indicated on the plans, meeting the requirements prescribed in Section 555. All eyebars and castings shall conform to the requirements therefor prescribed in Section 555. No welds will be permitted in truss rods, or in main members of trusses or girders. Construction Requirements 557.03 Workmanship. None but experienced bridge carpenters shall be employed and all framing shall be true and exact. Unless otherwise specified, nails and spikes shall be driven with just sufficient force to set the heads flush with the surface of the wood. Deep hammer marks in wood surfaces will be considered evidence of poor workmanship and sufficient cause for removal of the workman responsible for them. The workmanship on all metal parts shall conform to the requirements specified for those materials. 557.04 Storage of Materials. All lumber and timber on the site of the work shall be stacked to prevent warping. Untreated material shall be open-stacked at least 12 inches (305 mm) above the ground surface and so piled as to shed water. When required by the Engineer, it shall be protected from the weather by suitable covering. Creosoted timber shall be close-stacked and, when required by the Engineer, the stacks shall be covered with a 2-inch (50.8 mm) layer of earth. The ground underneath and in the vicinity of all stacks shall be cleared of weeds and rubbish. 557.05 Treated Timber. Treated timbers shall be framed before treatment and shall be handled carefully without dropping, breaking of outer fibers, or bruising or penetrating the surface with tools. Cant dogs, hooks, or pike poles shall not be used. In coastal waters, cutting and boring below highwater mark shall be avoided. All cuts in creosote treated piles, timber, and lumber, and all abrasions, after having been carefully trimmed, shall be coated with two applications of a mixture of 60 percent creosote oil and 40 percent roofing pitch or shall be brushcoated with at least three applications of hot creosote oil and covered with hot roofing pitch. All cuts and abrasions in timber or lumber, that have been treated with an oil-borne or water-borne preservative, shall be given three brush-coats with the same type of preservative used in the original treatment. This requirement may be waived if the timber and lumber are to be painted. Before driving bolts, all holes bored after treatment shall be impregnated with hot creosote oil by means of an approved bolt-hole treater. Any unfilled holes, after being treated with creosote oil, shall be plugged with creosoted plugs. 557.06 Untreated Timber. In structures of untreated timber, the surfaces named below shall be coated thoroughly with two coats of hot cresote oil before the timbers are assembled: ends, tops, and all contact surfaces of posts, sills, caps, floor beams, and stringers, all ends, joints, and contact surfaces of bracing and truss members. All surfaces of timber bumpers, the back faces of bulkheads, and of all other timber which is to be in contact with earth shall be similarly treated. 557.07 Holes for Bolts, Dowels, Rods, and Lag Screws. Holes for round driftbolts and dowels shall be bored with a bit one-sixteenth inch (1.59 mm) smaller in diameter than that of the bolt or dowel to be used. The diameters of holes for square driftbolts or dowels shall be equal to one side of the bolt or dowel. Holes for machine bolts shall be bored with a bit of the same diameter as that of the bolt. Holes for lag screws shall be bored with a bit not larger than the body of the screw at the base of the thread. 557.08 Bolts and Washers. Washers of the size and type specified shall be used in contact with all bolt heads or nuts that would otherwise be in contact with wood. Cast-iron washers shall have a thickness equal to the diameter of the bolt, and the diameter of the washer shall be four times its thickness. For malleable or plate washers the diameter or side dimensions of the square shall be equal to four times the diameter of the bolt, and the thickness shall be equal to one-half the diameter of the bolt. Cast-iron washers shall be used when the timber is in contact with the earth. All nuts shall be checked or burred effectively with a pointed tool after being finally tightened, to prevent turning. 557.09 Countersinking. Countersinking shall be done wherever smooth faces are required. Recesses formed for countersinking, except in railings, shall be painted with hot creosote oil and, after bolts or screws are in place, shall be filled with hot pitch. 557.10 Framing. Subject to the requirements of subsection 557.05 for treated timber, all lumber and timber shall be accurately cut and framed to a close fit so that the joints will have even bearing over the entire contact surfaces without shimming. Slabbing or trimming of treated piles for fitting sway or sash braces will not be permitted. The spaces intervening between the braces and the smaller piles shall be filled with treated blocks so that the bracing is securely fastened to the piles. 557.11 Framing Bents. Mud blocks shall be firmly and evenly bedded to solid bearing and tamped in place. Concrete pedestals for the support of framed bents shall be finished carefully so that sills or posts will bear evenly upon them. Dowels for anchoring sills and posts shall be set when the concrete is cast and shall project at least 6 inches (152 mm) above the tops of the pedestals. Sills shall have true and even bearing on mud blocks, piles, or pedestals. They shall be driftbolted with bolts extending into the mud blocks or piles at least 6 inches (152 mm). When possible, all earth shall be removed from contact with sills so that there will be a free circulation of air around the sills. 557.12 Caps for All Bents. Timber caps shall be placed to obtain even and uniform bearing over the tops of the supporting posts or piles and with their ends in alinement. All caps shall be secured by driftbolts, set approximately at the center and extending at least 9 inches (229 mm) into the posts or piles. 557.13 Bracing. The ends of bracing shall be bolted through the pile, post, cap, or still. Bracing at intermediate intersections with posts or piles shall be bolted, or spiked with wire or boat spikes, as indicated on the plans. In all cases spikes shall be used in addition to bolts. 557.14 Stringers. Stringers shall be sized at bearings and shall be placed in position so that knots near edges will be in the top portions of the stringers. Outside stringers may have butt joints with the ends cut on a taper, but interior stringers shall be lapped to take bearing over the full width of the floor beam or cap at each end. The lapped ends of untreated stringers shall be separated at least 1⁄2 inch (12.7 mm) for the circulation of air and shall be securely fastened by drift-bolting where specified. When stringers are two panels in length the joints shall be staggered. Cross-bridging between stringers shall be neatly and accurately framed and securely toe-nailed with at least two nails in each end. All cross-bridging members shall have full bearing at each end against the sides of stringers. Unless otherwise specified in the contract, crossbridging shall be placed at the center of each span. 557.15 Plank Floors. Plank shall be of the grade specified and shall be surfaced four sides (S4S). Single plank floors shall consist of a single thickness of planks supported on stringers. The planks shall be laid heart side down, with one-fourth-inch (6.35 mm) openings between them for seasoned material and with tight joints for unseasoned material. Each plank shall be securely spiked to each stringer. The planks shall be carefully graded as to thickness and so laid that no two adjacent planks shall vary in thickness by more than one-sixteenth of an inch (1.59 mm). Two-ply timber floors shall consist of two layers of flooring supported on stringers. The lower course shall be pressure-treated with creosote oil. The top course may be laid either diagonal or parallel to the centerline of roadway, as specified, and each floor piece shall be securely fastened to the lower course. Joints shall be staggered at least 3 feet (914 mm). If the top flooring is placed parallel to the centerline of the roadway, special care shall be taken to securely fasten the ends of the flooring. At each end of the bridge these members shall be beveled. 557.16 Laminated or Strip Floors. Pieces for laminated or strip floors shall have a nominal thickness of 2 inches (50.8 mm) and shall be surfaced one edge hit or miss %-inch (3.18 mm) scant (SIE-H or M 8-inch (3.18 mm) scant), and when so specified, shall be surfaced one side hit or miss %-inch (3.18 mm) scant (SIS-H or M 8-inch (3.18 mm) scant). The pieces shall be of the grade specified. They shall be placed on edge, at right angles to the centerline of roadway. Each piece shall be spiked to the preceding piece at each end and at approximately 18-inch (457 mm) intervals, with the spikes driven alternately near the top and bottom edges. The spikes shall be of sufficient length to pass through two pieces and at least halfway through the third piece. If timber stringers are used, every other piece shall be toenailed to every other stringer. The size of the spikes shall be as shown on the plans. When specified on the plans, the piece shall be securely attached to steel stringers by the use of approved galvanized metal clips. Care shall be taken to have each piece vertical and tight against the preceding one, and bearing evenly on all the stringers. Pieces shall be of sufficient length to bear on at least four stringers. No splicing of pieces between stringers will be allowed. End joints on any one stringer shall be no closer than every third piece. End joints in adjoining pieces shall be no closer than every second stringer. 557.17 Wheel Guards and Railings. Wheel guards and railings shall be accurately framed in accordance with the plans and erected true to line and grade. Unless otherwise specified, wheel guards, rails, and posts shall be surfaced on four sides (S4S). Wheel guards shall be laid in sections not less than 12 feet (3.66 m) long. All rails shall be squarely butt-jointed at the posts and the rails shall break joints. 557.18 Trusses. Trusses, when completed, shall show no irregularities of line. Chords shall be straight and true from end to end in horizontal projection and, in vertical projection, shall show a smooth curve through panel points conforming to the correct camber. All bearing surfaces and joints shall fit accurately. Uneven or rough cuts at the points of bearing will be cause for rejection of the piece containing the defect. 557.19 Drains. Drains shall be provided where indicated on the plans. They shall be constructed with galvanized iron linings and shall be arranged to discharge free of the structure. 557.20 Painting. Rails and rail posts shall be painted with three coats of white paint unless otherwise specified on the plans. Other parts of the structure shall be painted when so designated on the plans. 557.21 Cleaning Up. Upon completion and before final acceptance, the Contractor shall remove all falsework, falsework piling down to at least 2 feet (610 mm) below the finished ground line, excavated or unused materials, rubbish, and temporary buildings. He shall replace |