The surface shall be dry and free of dust and loose materials immediately before the application of the waterproofing. Waterproofing shall not be done in wet or freezing weather without written authorization from the Engineer. Asphalt shall be applied at a temperature between 300° and 350° F, and tar between 200° and 250° F. A coating of primer shall be applied and allowed to dry before any mop coat is applied. The fabric shall be so laid that drainage will be over, and not against or along, the laps. It shall be "shingled" so that there will be two thicknesses at all points. Edge laps shall be at least 4 inches and end laps at least 12 inches. One ply of fabric shall not touch another or the primed concrete surface since there must be three unbroken moppings. Beginning at the lowest point of the surface to be waterproofed, a primed section about 20 inches wide shall be mopped with the hot asphalt or tar. A strip of fabric of half the width of the roll shall be placed immediately on the hot asphalt or tar and pressed carefully into place so as to expel all entrapped air and obtain close conformity with the surface. This strip and an adjoining area of concrete surface, slightly more than one-half the width of a roll, shall then be mopped with hot asphalt or tar and a full-width strip of fabric shall be pressed into place as before, so as to cover completely the first strip. This second strip and an adjoining area of the concrete surface shall then be mopped with hot asphalt or tar and the third strip of fabric placed so as to lap the first strip by not less than 4 inches. This process shall be continued until the entire surface is covered, each strip of fabric lapping at least 4 inches over the last strip but one. The entire surface shall then be mopped with hot asphalt or tar. The work shall be so regulated that at the close of the day's work the required mopping shall have been applied to all the fabric in place. Special care shall be taken to insure that all laps are thoroughly sealed down. Under no circumstances shall one layer of fabric touch another layer at any point or touch the unmopped surface. In all cases the mopping on concrete shall cover the surface so that no gray spots appear, and on cloth it shall be sufficiently heavy to completely conceal the weave. On horizontal surfaces not less than 12 gallons of asphalt or tar shall be used for each 100 square feet of finished work, and on vertical surfaces not less than 15 gallons shall be used for each 100 square feet. At the edges of the membrane and at any points where it surrounds such appurtenances as drains or pipes, suitable provisions shall be made to prevent water from getting between the waterproofing and the concrete surface. All flashing at curbs and against girders, spandrel walls, etc., shall be done with separate sheets lapping the main membrane not less than 12 inches. Flashing shall be closely sealed either with a metal counterflashing or by embedding the upper edges of the flashing in a groove poured full of joint filler. Joints which are essentially open joints but which are not designed to provide for expansion shall first be caulked with oakum and lead wool and then filled with hot joint filler. Expansion joints, both horizontal and vertical, shall be provided with approved water stops in accordance with details on the plans and in Section 616. The membrane shall be installed across all expansion joints as detailed on the plans. At the ends of the structure, membrane shall be carried well down on the abutments and suitable provision made for all movement. 615.03A Bridge Deck Waterproofing. Except as provided herein, subsection 615.03 shall apply. Bridge deck waterproofing shall be composed of an asphalt prime coat, two layers of asphalt-coated glass fabric, and three moppings of asphalt, or other approved protective systems as indicated on the plans or in the special provisions. The asphalt prime coat shall be applied by brush or hand roller so as to penetrate the concrete and provide bond between the concrete and the waterproofing. Primer shall be applied at the rate of 0.05 to 0.10 gallons per square yard. Primer shall not be applied when the ambient air temperature is less than 35 degrees F and shall be allowed to cure a minimum of 4 hours prior to application of the waterproofing. Surfaces shall be dry so as to prevent the formation of steam when the hot asphalt is applied. No waterproofing shall be done in wet weather or when the temperature is below 50 degrees F. The bituminized glass fabric shall be shingled so that there will be at least two thicknesses at all points. Edge laps shall be at least 2 inches. One ply of fabric shall not touch another or the primed concrete surface, since there must be three unbroken moppings. The first strip of fabric shall be one-half the width of the roll; the second shall be full width of the roll lapped with full width of the first strip; the third shall be full width of the roll lapped one-half the width of the second strip plus 2 inches. Each succeeding strip shall lap one-half the width of the preceding strip so that there will be at least two layers of fabric at all points. No strips less than 12 inches wide shall be used. On horizontal surfaces not less than 3 gallons and not more than 4 gallons of asphalt mop coat shall be used for each mopping for each 100 sq. ft. of finished work; on vertical surfaces not less than 4 gallons and not more than 5 gallons for each mopping per 100 sq. ft. shall be used. Each strip of fabric shall be carefully pressed into place to eliminate all air bubbles and to provide a smooth flat surface. Waterproofing applied to surfaces which change abruptly in direction shall be reinforced at these points by application of an extra layer of fabric of suitable dimensions. The Engineer shall be considered the sole judge to determine an abrupt change. Care shall be taken to prevent damage to the waterproofing strips and course during the placing of the pavement or by any other construction operation. Planks, plywood, or suitable sheet material shall be laid over the waterproofing when any trucking or tracking is unavoidable. Any damage shall be repaired at no additional expense to the Government. A special waterproofing detail at the juncture of the concrete deck slab and the curb shall be installed as indicated on the plans and in conjunction with the placement of the bridge deck waterproofing. Approximately 12 inches of the waterproofing strip nearest the curbs shall be turned up into a specially provided recess directly beneath the face of the curb. Recess filler shall then be installed between the concrete deck and the underside of the curb and in front of the turned-up waterproofing. Waterproofing at the juncture of the deck slab and scuppers, expansion joints, manholes, etc., shall be accomplished by turning up the waterproofing at such junctures, with the waterproofing snug against the face to a point that will be flush with the wearing surface when placed. 615.04 Membrane Waterproofing with Mortar Protection. Waterproofing membrane to be protected with mortar shall be constructed in all particulars in accordance with the requirements of subsection 615.03. Every part of the membrane, except on undercut surfaces (the underside of parts of the structure the surface of which makes an angle of less than 90 degrees with a horizontal plane), shall then be covered with a course of reinforced mortar. This course shall have a nominal thickness of 2 inches and shall be reinforced with welded wire fabric of 6-inch mesh and No. 12 gage, or its equivalent, placed so as to lie midway between the top and bottom surfaces of the mortar. The top surface of the mortar course shall be troweled to a smooth, hard finish. The protective mortar course shall be cured by burlap held in close surface contact and kept wet for 72 hours. On undercut surfaces the membrane shall be protected with a layer of asphalt roll roofing laid in hot asphalt or tar instead of the mortar covering. The bituminous material used for this purpose shall be the same as that used in mopping the membrane. 615.05 Membrane Waterproofing with Asphalt Plank Protection. Waterproofing membrane to be protected with asphalt plank shall be constructed in accordance with the requirements of subsection 615.03. The membrane shall then be covered with asphalt plank. The plank shall be laid in regular, straight courses as indicated on the plans. Whole planks shall be used in all cases except as otherwise required for closures and for fitting around openings and obstructions. Closing and trimming pieces shall be cut carefully to size. Before the planks are laid, all surplus talc or other powder shall be removed from them with a stiff brush or broom. Each piece shall be laid in a mopping of hot asphalt or tar and the edges and ends of pieces in place shall be coated with the hot asphalt or tar before another piece is placed against them. Each individual piece shall be pressed tightly against the piece next to it and the completed work shall have a uniform, smooth surface without open joints. 615.06 Defective Work. Any membrane waterproofing that is found to leak at any time prior to the final acceptance of the contract shall be made watertight at the sole expense of the Contractor. Method of Measurement 615.07 The quantity to be paid for will be the number of square yards of waterproofing of the several kinds, completed and accepted. If a lump sum payment is to be made, measurement will be in accordance with subsection 109.02. Basis of Payment 615.08 The quantities, determined as provided above, will be paid for at the contract price per unit of measurement, 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. 615(3) Membrane waterproofing (asphalt) with mortar protection Square yard. Square yard. 615(6) Membrane waterproofing (tar) with asphalt plank protection 615(7) Membrane waterproofing ( ) 615(8) Bridge deck waterproofing.. Lump sum. Section 616.-WATER STOPS Description 616.01 This work shall consist of water stops formed of rubber, plastic compounds or sheet copper furnished and placed in expansion and construction joints in reasonably close conformity with these specifications and at the locations shown on the plans or ordered by the Engineer. Materials 616.02 Materials shall conform to the requirements of the following subsections: Construction Requirements 616.03 Copper Waterstops. Copper sheets for water stops shall be of the thickness, weight, width, and shape shown on the plans or ordered by the Engineer. The sheet copper in each joint, if not a single sheet, shall be segment pieces connected by soldering joints into a continuous watertight unit. 616.04 Rubber Waterstops. Splices shall be made watertight by vulcanizing or mechanical means, in accordance with the manufacturer's instructions. If splices are used, the Contractor shall make at least one preliminary field splice sample for testing by the Engineer. No splicing shall be done until tests indicate a tensile strength of at least 50 percent of the reported tensile strength of the unspliced rubber waterstop. 616.05 Plastic Waterstops. Splices shall be made watertight by a heating process, without damage to the plastic, in accordance with the manufacturer's instructions. Preliminary splice samples shall be made and tested in accordance with subsection 616.04 and no splices shall be made in the work until a tensile strength for splices of at least 80 percent of that reported for unspliced plastic waterstops is indicated by tests. 616.06 Placing Waterstops. Waterstops shall be carefully placed and supported at the locations shown on the plans. Precautions shall be taken so that the waterstops shall be neither displaced nor damaged by construction operations or other means. All surfaces of the waterstops shall be kept free from oil, grease, dried mortar, or any other foreign matter while the waterstop is being embedded in concrete. Means shall be used to insure that all portions of the waterstop designed for embedment shall be tightly enclosed by dense concrete. Method of Measurement 616.07 Unless a pay item for waterstops appears in the bid schedule, no measurement or direct payment will be made for the work of this section, but any such work will be considered as included for payment under Section 552. Except as provided for in subsection 109.02, no measurements will be made for lump sum payment when so designated in the bid schedule. Measurements of waterstops to be paid for by designated units will be made of the specified material acceptably placed as directed. Basis of Payment 616.08 The quantities, determined as provided above, will be paid for at the contract price per designated unit of measurement or lump sum as shown for each of the pay items listed below that appears in the bid schedule. Such price and payment will be full compensation for the work of this section. If none of the pay items listed below appear in the bid schedule, no direct payment will be made, but the work will be considered as a subsidiary obligation of the Contractor, included for payment in the contract price for various classes of concrete. Section 617.-STRUCTURAL-PLATE PIPE, PIPE-ARCHES, AND ARCHES Description 617.01 This work shall consist of structural-plate pipe, pipe-arches, and arches of the sizes, thicknesses, and dimensions shown on the plans, furnished and installed at such places as are designated on the plans or by the Engineer in reasonably close conformity with these specifications and the lines and grades shown on the plans or established by the Engineer. This work shall include the furnishing and construction of such joints and connections to pipes, catch basins, headwalls, etc., as may be required to complete the structure as shown on the plans. Materials 617.02 Materials shall conform to the requirements of the following subsections: Structural Steel Plate Pipe, Pipe Arches and Arches.. Aluminum Alloy Structural Plate for Pipe, Pipe Arch and Arches. Zinc dust-zinc oxide paint. . . . . 707.10 707.12 708.03 Materials for underpasses shall conform to the requirement of subsection 707.10 or 707.12 as applicable. Construction Requirements 617.03 Excavation, Bedding, and Backfill. Excavating, bedding, and backfilling shall be performed as prescribed in Sections 206 and 603 supplemented as follows: When filling around and over arches before headwalls are in place, the first fill material shall be placed midway between the ends of the arch, forming as narrow a ramp as possible, until the top of the arch is reached. The ramp shall be built evenly from both sides and the fill material shall be compacted as it is placed. After the two ramps have been built to the top of the arch, the remainder of the fill material shall be deposited from the top of the arch both ways from the center to the ends, and as evenly as possible on both sides of the arch. If the headwalls are built before any fill material is placed around and over the arch, the fill material shall first be placed adjacent to one headwall until the top of the arch is reached, after which it shall be dumped from the top of the arch toward the other headwall, with care being taken to deposit the material evenly on both sides of the arch. In multiple installations the procedure above specified shall be followed, but extreme care shall be used to bring the material up evenly on each side of each arch so that unequal pressure will be avoided. 617.04 Fabrication. Plates for sectional plate pipe, pipe arches and arches shall be fabricated in accordance with AASHTO M 167 or WW-P-405. Plates shall be formed to provide lap joints. The bolt holes shall be so punched that all plates having like dimensions, curvature, and the same number of bolts per foot of seam shall be interchangeable. Each plate shall be curved to the proper radius so that the cross-sectional dimensions of the finished structure will be as indicated on the plans. Plates for forming skewed or sloped ends shall be cut to give the angle of skew or slope specified. Burned edges shall be free from oxide and burrs, and shall present a workmanlike finish. Legible identification numerals shall be placed on each plate to designate its proper position in the finished structure. |