601PIPE DRAINS, PIPE UNDERDRAINS, AND FRENCH DRAINS

601.01 Description. This work shall consist of constructing pipe drains and

pipe underdrains of the required inside diameter, and constructing french drains consisting of trenches filled with aggregate. Pipe underdrains, pipe underdrains in backslopes, and pipe underdrains for structures shall be designated as follows. Type Description Pipe Underdrains, Type 1 A perforated pipe, encased in fabric, installed in a trench backfilled with fine aggregate. Pipe Underdrains, Type 2 A perforated pipe, without fabric, installed in a fabric lined trench backfilled with coarse aggregate. Pipe Underdrains, Type 3 A 4 in. (100 mm) pipe, without fabric but with narrower perforations, installed in a trench backfilled with a coarser fine aggregate. Pipe Underdrains (Special) A non-perforated pipe installed in a trench to outlet pipe underdrains, Type 1, 2, or 3. Backslope Drains, Type 1 A pipe underdrain, Type 1 installed in the backslope at a depth of 4 ft (1.2 m) or less. Backslope Drains, Type 2 A pipe underdrain, Type 1 installed in the backslope at a depth > 4 ft (1.2 m) but ≤ 8 ft (2.4 m). Backslope Drains, Type 3 A pipe underdrain, Type 1 installed in the backslope at a depth > 8 ft (2.4 m) but ≤ 12 ft (3.6 m). Pipe Underdrains for Structures A perforated pipe, without fabric, installed in a fabric lined trench backfilled with coarse or fine aggregate. Pipe Underdrains for Structures (Special) A non-perforated pipe installed in a trench to outlet pipe underdrains for structures.

601.02 Materials. Materials shall be according to the following.

601.03 Pipe Drain Installation. Pipe drains shall be installed at the locations

shown on the plans. The pipe shall be bedded in the underlying material to a depth not less than ten percent of the external diameter of the pipe and, where trenching is required, the trench shall have a width of not less than the external diameter of the pipe plus 18 in. (450 mm). The bottom of the trench shall be compacted in a manner meeting the approval of the Engineer. Joints and fittings may be assembled without gaskets or solvent cement if the joint is hand tight and the spigot enters the socket not less than 1/3 of the socket depth for solvent cement joints and full-depth for elastomeric gasket joints. The trench and prepared foundation shall be approved by the Engineer prior to placement of the pipe. The pipe shall be laid so that the flow line will be at the grade shown on the plans or established by the Engineer. The permissible minimum cover over a pipe shall be 6 in. (150 mm). Laying of pipes shall commence at the outlet end and proceed toward the inlet end with the pipes true to line and grade. The ends of the pipe shall be carefully cleaned before they are placed, and shall be placed to avoid unnecessary handling on the foundation. As each length of pipe is laid, the ends of the pipe shall be protected to prevent the entrance of any material. Longitudinal laps shall be placed at the sides and separate sections of pipe shall be joined with tightly drawn, approved connecting bands. The trench shall be backfilled with select material, meeting the approval of the Engineer, placed in 8 in. (200 mm) layers, loose measurement, and compacted to the Engineer's satisfaction. Material excavated from the trench, if it meets the approval of the Engineer, may be used for backfill. Unsuitable material and suitable material in excess of that required for backfilling shall be disposed of by the Contractor according to Article 202.03.

601.04 Pipe Underdrain Installation. Pipe underdrains placed along

pavement edges shall be outletted across the shoulder to the ditch approximately every 500 ft (150 m) and at all low points in the flow line of the underdrain using pipe underdrain (special) according to the details shown on the plans. Pipe underdrains may be outletted into a cross road culvert when the fill above the culvert is 5 ft (1.5 m) or less. When pipe underdrains are included in contracts involving pavement patching, the pipe underdrains shall be installed after patching operations. When pipe underdrains are being installed next to existing pavement and it is determined by the Engineer that the Contractor's equipment or method of excavation is causing the material under the pavement to become dislodged, the Contractor shall move the location of the trench laterally away from the pavement a sufficient distance so that edge sluffing will not occur under the pavement. No additional compensation Pipe Drains, Pipe Underdrains, and French Drains Art. 601.04 will be allowed the Contractor for any increases in cost or quantities of backfill material that may be caused by a change in the location of the pipe underdrain trench. When pipe underdrains are included in contracts with existing paved shoulders, the trench of the pipe underdrain and pipe underdrain (special) shall be backfilled with aggregate to within 8 in. (200 mm) of the surface of the existing shoulder. The top 8 in. (200 mm) of the trench shall then be backfilled with an IL-19.0L Low ESAL mixture meeting the requirements of Section 1030 and compacted to a density of not less than 90 percent of the theoretical density. Perforated pipe shall be placed with the perforations down and the pipe sections shall be joined securely with the appropriate coupling fittings or bands. Upgrade ends of all pipe installations shall be closed with suitable plugs to prevent entry of soil materials. No equipment shall be operated directly upon the completed pipe installation for longitudinal underdrains constructed along the edges of pavement or subbase. Unsuitable material and suitable material in excess of that required for backfilling shall be disposed of by the Contractor according to Article 202.03.

601.05 Concrete Headwalls. Concrete headwalls for pipe drains, pipe

underdrains (special), pipe underdrains for structures, and backslope drains shall be constructed at the locations and according to the details shown on the plans. The headwalls shall be either cast-in-place of Class SI concrete according to the applicable portions of Section 503, or shall be precast according to Section 1042. If a precast unit is used, the pipe shall be grouted and sealed to the headwall opening. The grout mixture shall be one part cement and two parts sand mixed with water. The headwalls shall be placed so that there is a six percent minimum slope on the invert. The uppermost point of the headwall shall be placed flush with the roadway slope. The earth side slopes adjacent to the headwall shall then be shaped to conform to the sides and toe of the headwall. The outlet end of the pipe shall be protected by a permanent rodent shield, upon placement of the pipe drain, pipe underdrain (special), or backslope drain. The rodent shield shall have the configuration shown on the plans and shall be constructed of hot dip galvanized steel industrial wire cloth. The cloth size shall be Pipe Drains, Pipe Underdrains, and French Drains Art. 601.07 5 x 7 in. (125 x 175 mm) minimum before fabrication of shield for 4 in. (100 mm) pipe. Other submitted designs for a removable rodent shield may be used with the approval of the Engineer. Unsuitable material and suitable material in excess of that required for backfilling shall be disposed of by the Contractor according to Article 202.03.

601.06 French Drains. French drains shall be constructed at the locations

and to the dimensions shown on plans. The trench shall be excavated to the required width and depth, leveled, and smoothed prior to filling with aggregate. The specified gradation of fine or coarse aggregate shall then be placed to the required depth and covered with the next specified layer of material. When the use of geotechnical fabric is specified for lining the trench, the fabric shall be delivered to the jobsite in such a manner to facilitate handling and incorporation into the work without damage. The fabric shall be stored out of direct sunlight. After the trench has been approved by the Engineer, the fabric shall be loosely rolled out so the center of the fabric is at the centerline of the excavated trench, and it will not tear when the aggregate is placed. When more than one section of fabric is used, the fabric shall overlap a minimum of 2 ft (600 mm). Enough fabric shall remain uncovered after the trench is filled to provide for fabric overlap at the top. During backfilling with angular aggregates, a minimum 6 in. (150 mm) cushion of the aggregate shall be carefully placed over the lined trench before end dumping larger aggregates out of trucks or other equipment. Following the backfilling operation, the fabric shall be lapped over the top and covered with the next specified material. Unsuitable material and suitable material in excess of that required for backfilling shall be disposed of by the Contractor according to Article 202.03.

601.07 Method of Measurement. Pipe drains, pipe underdrains, pipe

underdrains (special), pipe underdrains for structures, pipe underdrains for structures (special), and backslope drains will be measured for payment in feet (meters), in place. Measurement for pipe underdrain (special) and pipe underdrains for structures (special) will be made from the back of the headwall to the centerline of the longitudinal pipe underdrain. At any location where, due to the type of longitudinal pipe underdrain material being used, more than one pipe underdrain (special) is required, only one run of pipe underdrain (special) will be measured for payment. Aggregate used for french drains will be measured for payment in tons (metric tons) or in cubic yards (cubic meters) according to Article 311.08. Geotechnical fabric for french drains will be measured for payment in place and the area computed in square yards (square meters). The additional fabric required Art. 601.07 Pipe Drains, Pipe Underdrains, and French Drains for overlaps of individual sheets and overlaps at the top of the french drain will not be measured for payment. When pipe underdrains are included on contracts with existing paved shoulders, shoulder removal and replacement over the trench area, as specified in Article 601.04 will be measured for payment in place in feet (meters) along the pipe underdrain and the portion of the pipe underdrain (special) that is under the paved shoulder. Excavation in rock will be measured for payment according to Article 502.12.

601.08 Basis of Payment. Pipe drains will be paid for at the contract unit

price per foot (meter) for PIPE DRAINS, of the diameter specified, or of the kind of material and diameter specified. Pipe underdrains will be paid for at the contract unit price per foot (meter) for PIPE UNDERDRAINS, TYPE 1; or PIPE UNDERDRAINS, TYPE 2; of the diameter specified, or of the kind of material and diameter specified; or PIPE UNDERDRAINS, TYPE 3. Pipe underdrains (special) will be paid for at the contract unit price per foot (meter) for PIPE UNDERDRAINS (SPECIAL), of the diameter specified. Pipe underdrains installed in backslopes will be paid for at the contract unit price per foot (meter) for BACKSLOPE DRAINS, TYPE 1; BACKSLOPE DRAINS, TYPE 2; or BACKSLOPE DRAINS, TYPE 3; of the diameter specified. Pipe underdrains for structures will be paid for at the contract unit price per foot (meter) for PIPE UNDERDRAINS FOR STRUCTURES, of the diameter specified. Pipe underdrains for structures (special) will be paid for at the contract unit price per foot (meter) for PIPE UNDERDRAINS FOR STRUCTURES (SPECIAL), of the diameter specified. Concrete headwalls for pipe drains, pipe underdrains (special), pipe underdrains for structures, and backslope drains will be paid for at the contract unit price per each for CONCRETE HEADWALLS FOR PIPE DRAINS. When pipe underdrains are installed through existing paved shoulders, removing and replacing the existing paved shoulder will be paid for at the contract unit price per foot (meter) for SHOULDER REMOVAL AND REPLACEMENT. French drains will be paid for at the contract unit price per ton (metric ton) or cubic yard (cubic meter) for FRENCH DRAINS. Geotechnical fabric, when required for french drains, will be paid for at the contract unit price per square yard (square meter) for GEOTECHNICAL FABRIC FOR FRENCH DRAINS. Removal and replacement of unstable or unsuitable material will be paid for according to Article 109.04. Excavation in rock will be paid for according to Article 502.13. Catch Basin, Manhole, Inlet, Drainage Structure Art. 602.02 SECTION 602. CATCH BASIN, MANHOLE, INLET, DRAINAGE STRUCTURE, AND VALVE VAULT CONSTRUCTION, ADJUSTMENT, AND RECONSTRUCTION

602.01 Description. This work shall consist of constructing, adjusting, or

reconstructing catch basins, manholes, inlets, or valve vaults, with frames and grates or lids, and constructing drainage structures with frames and grates.

602.02 Materials. Materials shall be according to the following.

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