710.01 722 SECTION 710 – UNDERDRAINS
710.01 Description ................................ ................................ ................... 722
710.02 Materials ................................ ................................ ...................... 722
710.03 Kinds and Sizes of Underdrains ................................ ................... 723
710.04 Reserved ................................ ................................ ....................... 723
710.05 Aggregate Underdrains ................................ ................................ 723
710.06 Aggregate Underdrains (with Pipe) ................................ .............. 723
710.07 Filter Cloth and Aggregate Underdrain (with and without Pipe) . 724
710.08 Final Cleanup ................................ ................................ ............... 725
710.09 Method of Measurement ................................ .............................. 725
710.10 Basis of Payment ................................ ................................ .......... 726
DESCRIPTION
710.01 Description
This work consists of constructing underdrains composed of stone, gravel, slag, sand, or any one of these ma terials and perforated pipe, semi -circular drain pipe (with connections), or filter cloth, on prepared foundations at the locations shown on the Plans or as directed by the Engineer. The work shall include all necessary excavation and backfill, together w ith such work and materials as may be necessary to make connections with other drainage structures, as shown on the Plans. MATERIALS
710.02 Materials
Provide materials as specified in: Aggregate for Underdrains ................................ .................... 903.17 Joint Mor tar ................................ ................................ ........... 905.02 Pipe (Size shown on the Plans) ....... 914.03, 914.07, 915.02, 915.03 Polyvinyl Chloride (PVC) Underdrain Pipe .......................... 914.09 Geotextile ................................ ................................ ............... 921.12 710.03 723 710.03 Kinds and Sizes of Underdrains Construct underdrains of the kinds specified. Unless otherwise specified, circular pipe for underdrains shall have a diameter of 4 inches. Semi-circular pipe for underdrains shall have a diameter of 4 -5/8 inches. In the case of pipe, consider the size to mean the nominal inside diameter.
710.04 Reserved
CONSTRUCTION REQUIREMENTS
710.05 Aggregate Underdrains
Excavate trenches to receive the aggregate at the locations and to the dimensions shown on the Plans or as directed by the Engineer. Make the trench deep enough to intercept the water -bearing strata and provide it with a smooth and uniform finish. Place aggregate meeting the requirements of 903.17 in the trench in 6 -inch layers to the depth shown on the Plans. Tamp each layer with an approved tamp. Do not construct any underdrains that will not be paved over during the same construction season.
710.06 Aggregate Underdrains (with Pipe)
Excavate the trench to receive the pipe at the locations shown on the Plans or as directed by the Engineer. If the Plans do not show dimensions, construct the width of the trench to be not less than the outside diameter of the pipe plus 12 inches. Make the trench deep enough to intercept the water -bearing strata and to allow installation of the pipe and cover material. Unless otherwise shown on the Plans, spread a 2 -inch layer of aggregate on the bottom of the trench, compact it, and bring to a uniform grade. Ensure that the pipe is firmly embedded in the layer of aggregate. Lay perforated pipe with the flow sector and perforations at the bottom. If an underdrain is extended through a dry fill or other section where perforated pipe is undesirable, construct the underdrain with the pipe specified, and join sections by forming mortar joints or approved manufactured joints, or by using connecting bands. 710.07 724 After the pipe has been laid and approved, carefully backfill around the pipe with the specified aggregate in a manner that will not displace the pipe. Place the aggregate around and over the pipe in 6 -inch layers. Thoroughly tamp each layer with a vibratory compactor. Make lateral and other connections where shown on the Plans or as directed by the Engineer.
710.07 Filter Cloth and Aggregate Underdrain (with and without Pi pe)
A.Trench Excavation Excavate trenches at the locations and to the depth and width shown on the Plans. Prepare the sides and bottom of the trenches to a relatively smooth condition, free of sharp objects, obstructions, depressions, and debris that migh t damage the filter cloth during installation. Dispose of material removed from the trench outside of the right -of-way at locations obtained by the Contractor unless the Engineer authorizes its disposal within designated locations.
B.Filter Cloth Place geote xtile meeting 921.12 with the long dimension parallel to the centerline of the channel, laying it loosely without wrinkles or creases. When more than one width of filter cloth is necessary, overlap the joints a minimum of 12 inches. Insert securing pins with washers through both strips of overlapped material and into the material beneath, until the washer bears against the cloth and secures it firmly to the base material. Insert these securing pins through the overlapped cloth at not greater than 2-foot intervals along a line through the midpoint of the overlap. Protect the cloth at all times during construction to prevent contamination by surface runoff. Remove contaminated cloth and replace with uncontaminated cloth at no cos t to the Department. Replace cloth damaged during installation at no cost to the Department. Drop stone for overlaying on the cloth from a height no greater than 3 feet. Place the cloth so that the downstream edges overlap the upstream edges. Install th e filter cloth so that all splice joints are provided with a minimum overlap of 3 feet. Overlap the closure at the top of the trench as shown on the Plans, and secure with mechanical ties. Where outlet pipe passes through the fabric, use a separate piece of fabric of sufficient 710.08 725 size to be wrapped around the pipe and flared against the side of the filled drain fabric. Anchor field splices of filter cloth with securing pins as directed to maintain the required overlap. Take care when placing the aggregate filler and installing the pipe (when specified) to prevent damage to the filter cloth. To repair a torn, punctured, or otherwise damaged section, cut a piece of filter cloth large enough to cover the damaged area and overlap all around the damaged area a minimum of 12 inches.
C.Aggregate Underdrain Place the aggregate in 6 -inch layers, and compact each layer using a vibratory compactor to the satisfaction of the Engineer before making the filter cloth closure at the top of the trench. Protect the exposed en d of the outfall pipe by an endwall matching the existing slope. Bevel the end of the outfall pipe to fit the slope of the endwall. Should the outlet end of the pipe or the endwall fall within the limits of ditch paving, remove to neat lines that portion of the ditch paving within the endwall limits necessary to provide a connection with the new endwall, and make the endwall blend with the ditch paving.
710.08 Final Cleanup
Dispose of all excess or unsuitable material as directed by the Engineer. Perform final cleanup as specified in 104.10. COMPENSATION
710.09 Method of Measurement
The Department will measure for payment:
1.Aggregate Underdrains by the linear foot along the centerline of the underdrains, and from end to end of the underdrains, complete in place.
2.Filter Cloth Underdrains and Filter Cloth Underdrains (With Pipe) by the linear foot along the centerline of each type of Underdrain (with or without pipe) installed. 710.10 726 3. Lateral Underdrain by the linear foot, a s measured along the center of the outfall pipe from the center of the Filter Cloth Underdrain to the centroid of the beveled outfall end.
4.Lateral Endwalls by the unit, per each, for the type and size as indicated on the Plans.
5.6-inch Perforated Pipe with Vertical Drain System by the linear foot along the centerline of the underdrains, and from end to end of the underdrains, complete in place.
710.10 Basis of Payment
The Department will pay for accepted quantities of underdrains of the various kinds and sizes installed, complete in place, at the contract prices as follows: Item Pay Unit Aggregate Underdrains (With Pipe) Linear Feet Filter Cloth Underdrain Linear Feet Filter Cloth Underdrain (With Pipe) Linear Feet Lateral Underdrain Linear Feet Lateral Endwall Each Perforated Pipe with Vertical Drain System Linear Feet Such payment is full compensation for all excavation, backfill, connections, specials, and all other incidentals necessary to complete the work. Payment for Filter Cloth Underdrain i s full compensation for furnishing and installing the 4 -inch perforated underdrain pipe and pipe elbow when an underdrain outlet is required. Payment for Lateral Underdrain is full compensation for excavating the trench, furnishing and installing the outle t pipe and all materials, backfilling and compacting the trench, disposing of excess materials, returning the shoulder and slope to the previously existing normal condition, and for providing all tools, equipment, labor, and incidentals necessary to comple te this item of work. Payment for Lateral Endwalls is full compensation for excavation, concrete, backfill, compaction, disposal of excess material, and for all tools, equipment, labor, and incidentals necessary to complete this item of work. 710.10 727 Payment for 6 -inch Perforated Pipe with Vertical Drain System is full compensation for the pipe and pipe elbows, the installation of the materials including the polyethylene sheeting, and for all tools, equipment, labor, and incidentals necessary to complete this item of work. In cases where the Bulk SSD specific gravity of the mineral aggregate exceeds 2.85, the Department will adjust the tonnage of mineral aggregate for payment by multiplying the tonnage of mineral aggregate used by a specific gravity of 2.85 and dividing by the higher specific gravity. 711.01 728 SECTION 711 – CONCRETE MEDIAN BARRIER
711.01 Description ................................ ................................ ................... 728
711.02 Materials ................................ ................................ ...................... 728
711.03 Equipment ................................ ................................ .................... 729
711.04 Genera l ................................ ................................ ......................... 729
711.05 Finishing ................................ ................................ ...................... 729
711.06 Curing ................................ ................................ .......................... 730
711.07 Method of Measurement ................................ .............................. 730
711.08 Basis of Payment ................................ ................................ .......... 730
DESCRIPTION
711.01 Description
This work consists of constructing cement concrete median barriers on a prepared subgrade. MATERIALS
711.02 Materials
Provide materials as specified in: Portland Cement ................................ ................................ .... 901.01 Fine Aggr egate for Concrete ................................ .................. 903.01 Coarse Aggregate for Class A Concrete: Size No. 467, 57 or 67 ................................ .................... 903.03 Joint Filler, Preformed Type ................................ .................. 905.01 Steel Bar Reinforcement ................................ ........................ 907.01 Welded Steel Wire Fabric ................................ ...................... 907.03 Cement Concrete Curing Materials ................................ ........ 913.05 Water ................................ ................................ ...................... 921.01 Air-Entraining Admixtures ................................ .................... 921.06 For Portland ce ment concrete median barriers, use Class A concrete, meeting 604.
Source: Tennessee Standard Specifications for Road and Bridge Construction, 2021 Edition. Pages 731–736 of 1,072.