County-Specs-02720-Storm-Drainage.pdf

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GREENVILLE COUNTY

PUBLIC WORKS

STANDARD SPECIFICATIONS

SECTION 02720

STORM DRAINAGE

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STORM DRAINAGE

SECTION 02720

RELATED DOCUMENTS: Attention is directed to bidding requirements, contract documents, and general requirements which are binding in their entirety on this portion of the work and in particular to paragraphs concerning materials, workmanship, and substitutions.

General Conditions of the Contract and Special Conditions of the Contract shall apply to all Sections of the Work.

1.0 SCOPE

a. General Requirements: This section includes furnishing all labor, materials, and equipment for the installation of all drainage lines, including headwalls, inlets, catch basins, and other special appurtenances and structures as required for this project, shown on the drawings and specified herein.

b. Pipe Layout and Elevations: The layout of underground lines and invert elevations at governing points are shown on the drawings.

c. Inspection Required Before Backfilling: All pipe shall be inspected by the County inspector prior to backfilling operations.

d. Invert Elevations: All grades shown as pipe elevations are to the bottom of inside of pipe, unless otherwise noted.

e. Connections and Changes in Direction: All connections and changes of direction shall be made at inlets as shown.

f. Material Specifications: Where more than one material for an item is specified, the material used shall be as noted on the drawings or specified elsewhere in the Contract Documents.

g. Traffic Control: The Contractor shall be responsible for conducting all work in streets, roads, and highways in accordance with any and all Regulatory Authorities' current requirements. As a minimum, for any work in State Highways, the Contractor shall meet the requirements of Traffic Controls for Street and Highways Construction and Maintenance Operations, Part V of the South Carolina Manual on Uniform Traffic Control Devices for Streets and Highways - 1982, latest revision.

2.0 MATERIALS

Note: All ASTM references shall be the latest version for the specific product.

a. Concrete: Concrete shall be 3000 psi mix using Portland Cement ASTM C-50 Type 1, sand ASTM

C-33 and coarse aggregate ASTM C-33.

b. Rebar: Reinforcing bars shall conform to ASTM A 615, new billet steel, intermediate grade.

c. Water: Water shall be clean, free from oils, acids, alkalis, or organic or deleterious substances.

d. Reinforced Concrete Pipe (RCP): Reinforced concrete pipe shall be Tongue-and-Groove, Class III-Wall

B, unless otherwise indicated on the drawings and shall conform to requirements of ASTM C-76.

e. Gray Iron Castings: Frames, solid covers and grates for drainage structures shall be gray iron conforming to ASTM A-48, size as indicated, free from blow holes, porosity, hard spots, shrinkage distortion or other defects, well cleaned and coated with asphalt paint which shall result in smooth

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coating, tough and tenacious when cold, not tacky and not brittle. Bearing surface between frame and cover or grate shall be machined to prevent rocking and rattling.

f. Steps: Steps for manholes and drainage structures more than 4' deep shall be manufacturer's standard, spaced and embedded per OSHA requirements and approved by the Owner/Engineer.

g. Welded Wire Fabric: Welded wire fabric shall conform to ASTM A-185.

h. Masonry: Masonry materials for drainage structures are detailed on plans as concrete brick. Concrete manhole block and precast sections are equally acceptable, subject to design approval by the Owner/Engineer.

1. Concrete Brick: Concrete brick for storm inlets and catch basins shall be standard size, ASTM

C-90, Class A.

2. Concrete Block: Concrete block for storm drainage manholes shall comply with ASTM C-139.

3. Precast Manholes: Precast concrete manhole sections shall be 4000 psi concrete, tongue and groove, steel fabric reinforced, cement mortar joints bitumastic sealed, in accordance with ASTM C-478. Precast manholes shall have a conical top, coursed with brick. Precast bottoms are permissible. Handling holes shall be plugged with mortar or stoppers.

4. Portland Cement: Portland Cement shall be by an approved manufacturer, ASTM C-150, Type I.

5. Sand: Sand shall comply with ASTM C-144.

6. Lime: Lime shall be hydrated, ASTM C-207, Type N.

7. Water: Water for masonry materials shall be potable, free of suspended matter, injurious amounts of acids, or alkalis, and containing no industrial or domestic wastes.

8. Mortar: Mortar for drainage structures shall be 1 part of Portland Cement, 10% hydrated lime, 2 parts sand by volume, mixed with sufficient water to form a plastic mortar.

9. Flexible Butyl Resin Sealant: Flexible Butyl Resin Sealant shall comply with AASHTO specification

M-198 B, similar to Butyl Tite or ConSeal or approved equal.

i. PVC Pipe:

1. Polyvinyl Chloride (PVC) Pipe and Fittings (10-Inch Diameter and Smaller): ASTM D-3033 or ASTM D-3034, SDR 35, with ends suitable for either solvent cement or elastomeric gasket joints.

2. Polyvinyl Chloride (PVC) Perforated Pipe and Fittings: ASTM D-2729 with one-half inch diameter holes 5 to 8 inches on center, 120 degrees apart.

j. 2.17 Corrugated Aluminum Pipe and Fittings: Fed. Spec. WW-P-402 or AASHTO M-196, Class I or II, circular and arched; minimum thickness of metal shall be 18 gage.

k. 2.18 Corrugated Steel Pipe and Fittings: Fed. Spec. WW-P-405 and AASHTO M-36, Class I or II, circular and arched. Minimum thickness of metal shall be 18 gage. Pipe with annular corrugations shall be fully bituminous coated, half paved, for pipe diameters 18 inches and less. Pipe with helical corrugations shall be fully bituminous coated for pipe diameters 18 inches and less. Pipe larger than 18 inches diameter shall be fully bituminous coated and fully paved. Helical-corrugated pipe and fittings, when used with pipe joints, shall have a minimum of two factory-rolled annular corrugations at each end.

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l. Corrugated Metal Watertight Joints: Fed. Spec. WW-P-405 for steel pipe and WW-P-402 for aluminum pipe. The circumference of the coupling bands shall be provided with a 3 inch lap minimum. For tightening each coupling band, provide four 1/2 inch galvanized steel bolts. Gaskets shall be cylindrical in shape, fabricated of 3/8 inch thick by 6-1/2 inch minimum width rubber conforming to ASTM D-1056. Diameter of cylindrical gasket shall be 10 percent less than the nominal pipe diameter. On riveted pipe and fittings, omit the longitudinal seam rivets which would be under the coupling band and weld that portion of the seam. Coupling bands shall be of one or two piece construction and bituminous coated when specified for the pipe.

m. Filter Fabric: Woven or nonwoven polypropylene, nylon or polyester containing stabilizers and/or inhibitors to make the fabric resistant to deterioration from ultraviolet light. Filter cloth shall be of the type recommended by its manufacturer for the intended application.

n. Course Aggregate: The aggregate shall consist of washed crushed stone or gravel conforming to

SCHD "Standard Specifications for Highway Construction", Section 406.09.

o. Rip Rap:

1. Material Quality: Stones shall be hard quarry of field stone and shall be of such quality that they will not disintegrate on exposure to water weathering. The stone shall be suitable in all respects for the purpose intended and shall conform with SCHD "Standard Specifications for Highway Construction", Section 804 except as modified herein.

2. Hand Placed Rip Rap: Stone for hand placing to a thickness of 12 inches shall range in weight from a minimum of 25 pounds to a maximum of 150 pounds. At least 50 percent of the stone pieces shall weigh more than 60 pounds. The stone pieces, except spalls, shall have a minimum dimension of at least 12 inches. Stone for hand placing to a thickness of 6 inches shall be no less than 3 inches in one dimension and no less than 6 inches in another dimension.

3. Dumped Rip Rap: Stone used in dumped rip rap shall be a quarried stone of reasonably uniform grading from the larger to the smaller pieces with the larger pieces preferable not above 24 inches in size.

4. Grouted Rip Rap: Grouted rip rap stone shall conform to the requirements for hand placed rip rap.

The mortar for grout shall be composed of one part Portland Cement and three parts sand. The water content of the grout shall be such as to permit gravity flow into the interstices or voids with limited spading and brooming.

3.0 PIPE TRENCH EXCAVATION

a. Classification: Excavation shall be classified as defined in Section 02200.

b. Required Trench Dimensions: The trench shall be excavated by an approved method, to a depth to permit installation of the pipe along the lines and grades shown on the drawings. All side slopes for trench excavations shall be sloped by the Contractor to provide for safe working conditions by all personnel. The width of the trench shall be sufficient to allow thorough compacting of the backfill under and around the pipe. Where rock is encountered, the rock shall be removed to a depth below grade of at least 6 inches (6"), and the trench shall be refilled to grade with earth, sand, gravel, crushed stone or other suitable material as per the details on the drawings, firmly compacted to provide proper bedding for the pipe. Payment for rock will be to a depth of 6 inches below the invert and 12 inches on each side of the outside wall of the pipe.

c. Removal of Unsuitable Material: If directed by the Owner/Engineer, soft, mucky, or otherwise unstable or unsuitable material in the trench bottom shall be removed and replaced with crushed stone, or stabilized with crushed stone.

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d. Notification of Rock or Muck Excavation: The Contractor shall notify the Owner/Engineer immediately if "Rock Excavation" or "Muck Excavation" is encountered. Rock removal or backfill shall not proceed until directed by the Owner/Engineer. Section 02200, Article 10 Excavation shall apply to "Rock Excavation" in trenches.

4.0 BRACING AND SHEETING

a. General Requirements: The sides of all trenches and excavations shall be adequately braced and sheeted to protect personnel, structures and property from slides, cave-ins, or settlement and to maintain the work clear of all obstructions. Bracing, shoring and sheeting shall comply with all applicable safety regulations governing the work. Full responsibility for the design, type and strength of shoring, sheeting and bracing shall rest with the Contractor.

5.0 DEWATERING

a. General Requirements: The Contractor shall do all pumping necessary for dewatering trenches and to provide safe, proper work conditions for installation of pipe and appurtenances. Pipe shall be installed on dry, stable trench bottoms.

6.0 BACKFILLING

a. General Requirements: Immediately after the pipes have been laid and checked, the trench shall be backfilled around the barrel of the pipe with fine materials, free, from large stones deposited in level layers no more than 6 inches (6") in depth, each layer to be thoroughly tamped and compacted before the next layer is deposited. Care should be exercised to avoid any wedging action or eccentric action upon or against any pipe or structure and to avoid any disturbance or damage to the work.

b. Backfilling in Traffic Areas: In roads, across sidewalks and driveways and at other places subject to vehicular traffic or other superimposed loads, trench backfilling material as specified above shall be compacted in 6 inch (6") layers for the full depth of the trench and consolidated in such a manner to provide an unyielding foundation for vehicular traffic. Unless otherwise shown on the plans or required by governing authorities, the compaction density shall be equal to the density of the original adjacent material. However, the minimum compaction density shall be 95% of maximum density according to ASTM D-698, except that the upper 18 inches (18") under the roadway and parking lots shall be compacted to 100% of maximum density.

c. Backfilling in Other Areas Subject to Superimposed Loads: Material for the lower portion of the trench, above required pipe bedding material, shall consist of fine, loose earth, free of large clods, stones, vegetable matter, debris, and/or other objectionable material. It shall have a moisture content suitable for thorough compaction. It shall be deposited in horizontal layers not to exceed 6 inches (6") in thickness (before compaction) on each side of the pipe. Each layer shall be thoroughly tamped or rammed around the pipe with approved hand or power driven tools until enough material has been placed and compacted to provide a cover of not less than 18 inches (18") over the top of the pipe, or as otherwise shown on the plans or as directed by the County Engineer. Minimum compaction shall be 95% of maximum density according to ASTM D-698.

d. Backfilling in Areas Not Subject to Superimposed Loads: In all other areas not subject to superimposed loads, trench backfill may be placed from the level 18 inches (18") above the top of the pipe upward in 12 inch (12") layers with light compaction by mechanical tampers, and without damage to the pipe.

Such backfill may contain coarser material than specified in Paragraph 6 (c) above, but shall be free from brush, trash, perishable matter, or stones larger than 6 inches (6") in any dimension.

e. Maximum Stone Size: No rock or boulders shall be used in the backfill for at least one foot (1') above the top of the pipe and in the upper 18 inches (18"). No stone larger than six inches (6") in its greatest dimension shall be used in the backfilling.

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f. Insufficient Fill Quantity: Any deficiency in the quantity of material for backfilling the trenches, or for filling depressions caused by settlement, shall be supplied by the Contractor as part of the Scope of Work.

7.0 DRAINAGE LINE CONSTRUCTION

a. Installation of Pipe

1. General Requirements: Under no circumstances shall pipe be laid in water, on rock, or when trench conditions of weather is unsafe or unsuitable for such work. Each pipe shall be carefully examined by the Contractor before being laid, and any defective or damaged pipe shall be removed from the site. Proper equipment shall be provided for lowering sections of pipe into trenches. The pipe shall be laid true to line and grade, beginning at the lowest point with the spigot end pointing in the direction of flow, with uniform bearing upon the pipe bed for the full length of its barrel. Raising the pipe off the subgrade (bridging) to obtain the proper elevation will not be allowed. Each section shall be securely attached to the adjoining sections by the method required for the type of joint used.

When laying concrete pipe, all joints shall be thoroughly wetted with water and then filled with a stiff mortar composed of one part Portland Cement and two parts sand. The mortar shall be placed so as to form a durable water tight joint. The lower portion of the hub or groove of each section of pipe laid shall be thoroughly wetted and plastered on the inside with cement mortar of sufficient thickness to bring the inner surfaces of the abutting pipes flush and even. As each section of the pipe is put in place, the remainder of the joint so formed shall be thoroughly wetted and filled with mortar, and sufficient additional mortar shall be used to form a bead along the outside of the joint.

The inside of the joint shall be wiped and finished smoothly. After the initial set, the mortar on the outside shall be protected from the air and sun with thoroughly wetted earth or burlap cover.

2. Optional Joint Sealant: As an option, each joint connection of pipe shall be made watertight using a flexible Butyl Resin Sealant according to the manufacturer's specification.

3. Reinstallation of Substandard Pipe: Any pipe which is not in true alignment, is damaged, or which shows undue settlement after laying shall be removed and reinstalled without extra compensation.

4. Joint and Fitting Installation: Pipe joints and fittings shall be made up in strict accordance with the manufacturer's directions.

5. Laser Alignment Control: Laser beams shall be used for grading pipe trenches and placing pipe.

b. Drainage Structures

1. General Requirements: Drainage structures shall be constructed as shown on the drawings, walls of brick, plumb and true, bottoms of concrete.

2. Brickwork: All brick shall be wet before being laid in warm weather. Brick shall not be laid in freezing weather. The Contractor shall protect all brick work from the weather when storming or freezing;

and at all times when necessary during the progress of the work.

3. Setting Frames: Cast iron frames shall be set in a full bed of mortar and to the elevation established by the Owner/Engineer.

4. Backfilling: Backfilling around drainage structures shall be accomplished by methods and requirements as specified for backfilling pipe trenches.

c. Headwalls

1. General Requirements: Headwalls shall be constructed at locations indicated on the drawings, with the headwall details. Concrete and reinforcing bars shall be as specified.

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d. Subdrain Systems

1. Procedure: Refill excavations cut below indicated depth with granular fill during placement of granular fill. Trenches for underdrain shall be excavated to a width equal to 3 times the outside diameter of the pipe and to a depth as required to lay the pipe at the desired grade. Provide granular fill a minimum of one pipe diameter on each side of the pipe and on the bottom of the pipe.

Place in 6 inch lifts up to the level indicated or directed by the Landscape Architect. The pipe shall be placed in the center of the trench and bedded firmly on the bottom course of aggregate. If bell and spigot type is used, the bell end shall be laid upstream. Perforated pipe shall be laid with the perforations on the underside of the pipe. Lateral connections shall be made with suitable tee, wye, bend, reducer, or increaser fittings as required. The upstream end not terminating in a structure shall be capped, plugged, or fitted as directed by the Landscape Architect

2. Wrapping Perforated Pipe: Wrap PVC perforated pipe when indicated, with one layer of filter cloth, overlapping 6 inches at the longitudinal joint of the filter cloth. Wrap the filter cloth such that the edge of the outer layer points towards the bottom of the trench at the longitudinal joint and is in direct contact with the inner layer of the filter cloth. Obtain approval of filter cloth installation before placing fill. Place fill in a manner to prevent filter cloth damage or displacement.

3. Wrapping Drainage Trench: Provide a layer of filter cloth around the perimeter of the drainage trench. Filter cloth joints placed on the side of the drainage trench shall have the inner layer of filter cloth pointing towards the bottom of the trench. Unless specified otherwise, overlap filter cloth at joint a minimum of one foot. Repair damaged filter cloth by placing an additional layer of filter cloth over the damaged area, overlapping one foot in all directions.

e. Placing Rip Rap

1. Hand Placed Rip Rap: The thickness of hand placed rip rap shall be no less than that specified, measured perpendicular to the slope. The slope upon which this rip rap is to be placed shall conform with the cross section shown on the plans or as directed by the Landscape Architect.

Depressions that may be filled in trimming and shaping shall be properly compacted. Rip Rap shall be firmly imbedded against the slope and the adjoining piece with the sides in contact and with well broken joints. The spaces between the larger pieces shall be filled with spalls of suitable size which shall be thoroughly rammed into place. The finished surface shall present an even, tight surface true to line, grade and section.

2. Dumped Rip Rap: Before placing of rip rap, the slopes and foundation trenches shall be constructed as necessary. The stone shall be handled or dumped into place so to produce a compact, well graded mass with a minimum percentage of voids. The material shall be placed to its full course thickness of 2 feet minimum, measured perpendicular to the slope, in one operation and in such manner that the slopes will be disturbed as little as possible. The larger pieces shall be well distributed and the finished layer of rock shall contain no segregated pockets of small pieces or groups of large pieces which would cause large open voids. Rearranging of the individual pieces by mechanical equipment, or by hand, may be required to the extent necessary to obtain a reasonably well graded distribution of sized as specified above. The surface of the completed rip rap shall be reasonably uniform in appearance, free from excessive humps or depressions.

3. Grouted Rip Rap: The aggregate, and method of placing the rip rap for grouted rip rap shall be as specified for hand placed rip rap. After the rip rap has been placed and approved, all interstices or voids between the stone shall be filled with mortar to a depth of not less than 4 inches below the surface of the stone. The face or surface of the stones shall be left reasonably free of grout.

Plastering of the rip rap will not be permitted. The spaces between the stones shall be reasonably free of sand or other material and shall be wet during the placing of the grout.

f. Cleaning, Inspection and Testing

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1. General Requirements: All storm lines, and drainage structures upon completion or at such time as directed shall be cleaned, inspected, and tested. The storm drain system shall have a true grade and line and shall be entirely clean and ready for use.

8.0 SITE CLEAN UP

a. General Requirements: The Contractor shall remove all excess material from excavations to points designated by the Owner/Engineer, and clean the site of the work of all debris collected during the construction.

END OF SECTION