680 Page 475680 UNDERDRAINS
680.1DESCRIPTION
This work consists of installations of porous backfill, drainage tubing, and headwalls for subgrade drainage.
680.2MATERIALS
A.Porous Backfill: Porous backfill for underdrains will conform to Section 800, with the following modifications: The material will consist of natural sand. Crushed material is not acceptable. The percentage of material passing a #200 sieve will not exceed 2.0%. Quality testing will not be required. B.Impermeable Plastic Membrane: Impermeable plastic membrane, when required, will conform to C.Corrugated Polyethylene Drainage Tubing: Corrugated polyethylene drainage tubing will conform to Section 990. D.PVC Pipe: In lieu of corrugated polyethylene tubing a profiled wall PVC pipe may be substituted. PVC pipe and fittings will meet the physical requirement specified for polyethylene pipe and will meet the material requirements of ASTM D3034, except dimensions at time of manufacture. E.Concrete: Concrete for headwalls will conform to Class M6, Section 462.
680.3CONSTRUCTION REQUIREMENTS
The trench to receive the porous backfill will be excavated to the lines shown on the plans or as staked by the Engineer. The trench bottom will be shaped and tamped as required by the Engineer. Disposal of surplus excavation will be the responsibility of the Contractor. The porous backfill material will be placed in 1 foot layers without compaction. The backfill will be uniformly spread without segregation or contamination. Tarpaulins or other approved devices will be used as guides from the hauling vehicle to the trench to prevent pulling dirt in with the backfill. Clear and unobstructed outlets will be provided for all drains. Where possible, all outlets will have a 12 inch free fall and will be properly marked and protected with a 4 inch by 4 inch by 6 foot guide post painted with two coats of white paint. Drain installations and waste disposal areas will be shaped and left in a neat appearing condition satisfactory to the Engineer.
680.4METHOD OF MEASUREMENT
A.Porous Backfill: Porous backfill will be measured, to the nearest 0.1 ton. Material used to fill unauthorized trench widths or other dimensions will not be measured for payment. 680 Page 476B.Underdrain Pipe: Underdrain pipe will be measured parallel to the pipe to the nearest foot. C.Concrete Headwall for Drain: Concrete headwall for underdrain will be measured by the number of headwalls installed.
680.5BASIS OF PAYMENT
A.Porous Backfill: Porous backfill will be paid for at the contract unit price per ton. Payment will include full compensation for furnishing the material, labor, equipment, and incidentals necessary. B.Underdrain Pipe: Underdrain pipe will be paid for at the contract unit price per foot for the various types and classes of pipe, inclusive of necessary bands, bolts, wyes, elbows, grates, lids, covers, guideposts, screens, breathers, excavation, backfilling, and handling waste disposal. C.Concrete Headwall for Drain: Concrete headwall for underdrain will be paid for at the contract unit price per each. 700 Page 477700 RIPRAP
700.1DESCRIPTION
This work consists of furnishing and placing approved material for the protection of piers, abutments, walls, embankments, and other designated locations.
700.2MATERIALS
A.Riprap: Riprap will conform to Section 830. B.Drainage Fabric: Drainage fabric will conform to Section 831, Type B.
700.3CONSTRUCTION REQUIREMENTS
Slopes to be protected by riprap will be free of brush, trees, stumps, and other objectionable material and will be dressed to a smooth surface. Soft or spongy material will be removed to the specified depth and replaced with approved material. Filled areas will be thoroughly compacted. All excavation required to construct the slope to the configuration detailed in the plans will be incidental to the payment for riprap. When drainage fabric is specified on the plans, the surface to be covered will be smooth, free of obstructions, and will conform to plan shown dimensions prior to placement of the drainage fabric. The drainage fabric will be placed under and along all sides of the riprap that are in contact with earth, unless otherwise shown on the plans. Lapped joints in the drainage fabric will be placed transverse to the direction of flow with the overlap in the direction of flow. All lapped joints will be lapped a minimum of 1 foot. Vehicles and equipment will not be operated directly on the drainage fabric. Protection for structure foundations will be provided as early as the foundation construction permits. The area to be protected will be cleaned of waste materials. Riprap will be placed in a manner which will produce a reasonably well graded mass of stone with the minimum practicable percentage of voids. Riprap will be placed to its full course thickness in one operation without displacing the underlying material. Bridge berms, channel slopes/bottoms, and other surfaces that will be covered with riprap will be finished to an elevation that will permit the placement of the required depth of riprap and match plan elevations or existing channels. Placing of riprap in layers, or by dumping into chutes, or similar methods likely to cause segregation will not be permitted. The larger stones will be well distributed and the entire mass of stone will conform to the gradation specified. In order to produce a compact riprap protection in which all sizes of material are placed in their proper proportions, hand placing or rearranging of individual stones by mechanical equipment may be required. The riprap protection will be placed in conjunction with the construction of the embankment. To prevent mixture of embankment and riprap, sufficient lag in construction of the riprap may be necessary. The Contractor will maintain the riprap protection until accepted. Material displaced by any cause will be replaced.