Method of Measurement 630.05 The quantity to be paid for will be the number of cubic yards of gabions completed, accepted and measured in accordance with measurement of quantities, Section 109.01. The granular backfill material to be paid for will be the number of cubic yards, measured within the pay limits as shown on the plans or as directed by the Engineer, complete in place and accepted. If the original ground is excavated beyond the pay limits the Contractor shall backfill this area with granular backfill material at his own expense. Basis of Payment 630.06 The quantities, determined as provided above, will be paid for at the contract price per unit of measurement for the pay item listed below, which price and payment shall constitute full compensation for furnishing and placing wire baskets and rock, and for all labor, equipment accessories, and tools necessary to complete the work described in this section. 631.01 This work shall consist of the construction of concrete, steel, and timber crib type retaining walls, and aluminum cylindrical type retaining walls, in accordance with these specifications and in reasonably close conformity with the lines and grades shown on the plan or established by the Engineer. Materials 631.02 Materials. Materials shall meet the requirements specified in the following sections or subsections and as specified below: Design of the retaining wall members shall be as shown on the plans. However, minor variations in design and dimensions will be permitted to allow manufacturer's standards, subject to approval in writing by the Engineer. (a) Reinforced Concrete Crib Type Retaining Wall. Crib members shall be constructed of portland cement concrete in accordance with the requirements of Section 552. The maximum size of the aggregate shall be one inch. If specified, concrete crib members shall contain emulsified carbon black in an amount not to exceed 1/2 pound per bag of cement. Concrete crib members shall be free of cracks, depressions and spalled, patched, or plastered surfaces or edges, or any other defect which may impair their strength or durability. (b) Steel Crib Type Retaining Wall. Crib members shall consist of steel spacers and stretchers with all appurtenances necessary for complete assembly in the field. Sheets from which all spacers and stretchers are manufactured shall be made of material conforming to the requirements of Section 719.19. Each spacer and stretcher shall be fabricated completely in the plant prior to shipment to the site. If indicated on the plans, fillers for placing between stretchers on the face of the wall and end caps for outside end of spacers will be furnished. The various members of the crib shall be constructed of steel sheets of the thickness called for on the plans. Details of crib members shall be shown on the plans, except that the Contractor may be permitted to furnish metal crib members of other equivalent designs approved in writing by the Engineer. In such case, he shall submit detailed specifications and plans for approval by the Engineer and such plans must be approved before delivery of material is begun. Bolts and nuts shall conform to the specifications of ASTM A 307, Grade A. The bolts shall be of the size shown on the plans and, at the option of the Contractor, shall either have heavy hexagon heads and nuts without washers, or hexagon heads and nuts with plate washers under the heads and nuts. Washers shall be round steel plate washers, 0.129-inch thick, minimum, including coating, with holes not more than 16-inch larger than the diameter of the bolt. Bolts, nuts, and washers shall be galvanized in accordance with the specifications of ASTM A 153. (c) Treated Timber Crib Type Retaining Wall. Treated timber shall meet the requirements shown on the plans or in the special provisions. Hardware shall meet the applicable requirements of subsection 716.02. (d) Aluminum Cylindrical type Retaining Wall. Aluminum alloy sheet used in fabricating cells and facing sheets shall conform to the requirements of Federal Specification WW-P-402. Bolts for connecting cells and facing sheets shall not be less than 2-inch diameter. The threads shall be American Standard Coarse Thread Series, Class 2, free fit. Aluminum bolt and nut material shall conform to the requirements of ASTM B 211, Alloy 6061. Where thicknesses of metal are not specified or shown on the drawings, the thickness of metal furnished shall be as recommended by the fabricator of the member and shall be as required to develop fully the strength of each member. All members or parts shall be fabricated completely in the plant prior to shipment to the site, except that all facing sheet bolt holes shall be field drilled to the bins using the facing sheets as a templet. All units shall be fully interchangeable. No drilling, punching, or drifting to correct defects in manufacture will be permitted. Any member or parts having holes improperly punched or drilled shall be replaced. Construction Requirements 631.03 Foundation. Foundations shall be prepared in accordance with the requirements of Section 206. Bed course material shall be placed and compacted to form a bed course of the required thickness. The prepared foundation or bed for the retaining wall shall be firm and normal to the face of the wall, and shall have been approved by the Engineer before any of the wall is placed. In areas where foundation materials are not acceptable to the Engineer, material shall be excavated to the depth directed by the Engineer, refilled with bed course material, and compacted to a dry density of at least 95 percent of the maximum dry density as determined by AASHTO T 99, Method C. This excavation shall extend a sufficient distance horizontally beyond the toe of the wall to provide load distribution. Underdrain, when required, shall be installed prior to placing of the wall, and in accordance with the requirements of Section 605. 631.04 Erection. The wall members shall be erected as shown on the plans or in conformance with the fabricator's or manufacturer's recommendations and instructions. Wall members shall be carefully handled and erected in such manner as to avoid any damage. Any members which become cracked or otherwise damaged during erection shall be completely removed and replaced at the Contractor's expense. In the construction of a crib type wall on a curve, the proper curvature for the face shall be obtained by the use of shorter stringers in the front or rear panels of the walls as shown on the drawings. All necessary bolts and hardware shall be furnished for complete assembly of the units into a continuous wall of connected units. (a) Reinforced Concrete Crib Type Retaining Wall. Excavation for the site of the concrete crib shall be made to the elevations shown on the drawings. When the wall is to be set upon a solid rock foundation, an 8-inch minimum layer of bed course material shall be placed under each base plate. Special care shall be taken so that the foundation bearing material key at the toe of the wall is not destroyed during the site preparation. The units shall be erected as shown on the drawings. (b) Steel Crib Type Retaining Wall. Crib members shall be erected as shown on the plans. Bolts shall be torqued to not less than 25 foot-pounds. (c) Treated Timber Crib Type Retaining Wall. Crib type wall of the various types shall be constructed as shown on the plans and in accordance with the applicable construction requirements of Section 557. All drilling and attachment of hardware shall be performed in accordance with the applicable provisions of Section 557. (d) Aluminum Cylindrical Type Retaining Wall. Excavation for the site of the circular cells shall be made to the elevation as shown on the drawings. The prepared foundation for the individual cells shall be firm and normal to the face of the wall. Special care shall be taken so that the foundation bearing materil key at the toe of the cell is not destroyed during the site preparation. The units shall be erected as shown on the drawings. Any members twisted, bent, or with holes improperly located shall be replaced. In the construction of a wall on a curve, the proper curvature for the face shall be obtained by situation of the individual cells consistent with facing sheet spacing. The cell height and diameter may be varied. Two or more cell designs, as shown on the drawings, may be incorporated into the same wall. Necessary bolts and facing sheets shall be furnished for complete assembly of the cells into a continuous closed face wall. All bolts shall be torqued to at least 25 foot-pounds. Aluminum washers shall be placed on the inside of cells where the facing sheet bolts to the cell and shall be two inches outer diameter, inside diameter 16 inch larger than bolt diameter, and 0.090 inch thick. Vertical joints in the sheets forming the cell walls shall be drilled or punched with a double row of 16-inch diameter holes on 3-inch centers to match the crests and valleys of the corrugations. The centerline of the outer row of holes shall be not less than 3⁄4/4-inch from the ends of the sheet and the gage between rows of holes shall be not less than 1-1⁄2 inch. The horizontal joints for all sheets shall be drilled or punched with a single row of 16-inch diameter holes spaced not less than 18 inches or greater than 21 inches. The centerline of the row of holes shall be centered on the crest or valleys of the corrugation and shall be not less than 4 inch from the edge of the sheet. The facing sheets shall be drilled or punched with a single row of 16-inch diameter holes spaced on 6-inch centers to match the crests of the corrugations, and the centerline of the row of holes shall not be less than 1-1⁄4-inch or more than 1-3/8 inch from the end of the sheets. 631.05 Backfilling Wall. The cells formed by the wall members shall be backfilled with granular backfill material. Granular backfill material shall also be placed back of and beyond each retaining wall to the depths and dimensions shown on the plans. Backfilling shall conform to the requirements of Section 206. Filling of the interior of the walls or cells may progress simultaneously with the erection of the walls or cells. The granular backfill material shall be placed in approximately 6-inch layers and tamped or compacted. Each layer shall be compacted to a density of at least 95 percent of the maximum dry density as determined by AASHTO T 99, Method C. Method of Measurement 631.06 The quantity of reinforced concrete, steel, and treated timber crib type retaining walls to be paid for will be the number of square feet of facial area for each type, complete in place and accepted. Measurements will be made on the plane of the face, and will be made to the outermost elements of the structure. The quantity of aluminum cylindrical type retaining wall to be paid for will be the number of square feet in the outside face of the wall, complete in place and accepted. Facial area for circular bins shall consist of the diameter multiplied by the height of each cell. Bed course and granular backfill material will be measured by the ton or cubic yard. Reinforcing steel will not be measured for payment, but will be considered as a subsidiary obligation of the Contractor under this section. Basis of Payment 631.07 The quantities, measured 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, which price and payment will be full compensation for furnishing and placing all material, including all labor, equipment, tools, and incidentals necessary to complete work prescribed in this section, except structure excavation will be paid for under Section 206 and granular backfill filter material for underdrains and perforated metal pipe for underdrains will be paid for as specified in Section 605. 632.01 This work shall consist of slope paving, of the type or types called for in the bid schedule, constructed in accordance with these specifications, and in reasonably close conformity with the lines, grades, and dimensions shown on the plans. Materials 632.02 Materials shall meet the requirements of the following sections or subsections: 632.03 The foundation bed shall be constructed to the required elevation below the finished surface of the slope and shall be compacted and shaped to a smooth, uniform surface. Concrete shall be placed in accordance with the applicable requirements of Section 552. Construction joints shall be as shown on the plans. Welded wire fabric shall be placed at the center of the slab, shall run continuous through construction joints, and the adjacent runs of fabric shall lap not less than 6 inches. Finishing of the concrete slope paving shall conform to the requirements of subsection 552.12(c), except the finished surface shall vary not more than 1⁄2 inch along a 10-foot straightedge. The bricks, masonry blocks, or stones shall be founded on the foundation bed with flat faces up and their longest dimension parallel to the centerline of the gutter. Joints shall be broken and shall not exceed 1 inch in width. After each brick, masonary block, or stone has been rammed into place and the surface is satisfactory, mortar shall be applied on its exposed side in such quantities that when the adjacent stone is placed and rammed into position the mortar shall fill, to within an inch of the surface, the interstices between the brick or stone, but shall not protrude above their tops. The finished brick, masonry blocks, or stone surface shall be free from mortar stain. Method of Measurement 632.04 The quantity to be paid for will be the number of square yards, surface measurement, of slope paving completed and accepted. Basis of Payment 632.05 The quantity, determined as provided above, shall be paid for at the contract price per unit of measurement for the pay item listed below, as shown on the bid schedule which price and payment will be full compensation for furnishing and placing all materials, including all labor, equipment, tools and incidentals necessary to complete the work prescribed in this section. No direct payment will be made for any excavating or work necessary in preparing the subgrade or any backfilling required. |