420Section 420

420.01 This work consists of furnishing and installing geotextiles and geomembranes for

paving, impervious lining, erosion control, drainage, separators and landscape weed barrier. MATERIALS

420.02 Geotextiles and geomembranes shall meet the applicable requirements of subsections

712.07 and 712.08 for the use intended. Geotextiles for erosion control for drainage or for

separators may be Class 1, Class 2, or Class 3, conforming to subsection 712.08, if the class is not specified on the plans. Asphalt cement binder for the paving geotextile shall be the same grade as the asphalt cement used for Item 403. Paving geotextile shall be a minimum Class 3, conforming to subsection 712.08. CONSTRUCTION REQUIREMENTS

420.03 Areas where the geosynthetic is to be placed shall have a uniform slope, be

reasonably smooth, free from mounds and windrows, and free of any debris or projections that could damage the material. Riprap or cobbles placed on the geosynthetic shall not be dropped from a free fall greater than 3 feet. The cushion layer or initial layer of riprap may require careful placement without free fall to avoid geosynthetic damage. Geosynthetics damaged or displaced before or d uring placement of overlying layers shall be replaced or repaired per the requirements of this section and to the satisfaction of the Engineer, at the Contractor’s expense.

420.04 Paving. The areas to be treated shall be as designated on the plans. The pavement

surface shall be broomed clean immediately before beginning the crack reduction geotextile treatment using a self -propelled power broom. The asphalt cement binder shall be applied to the pavement surface at the rate of approximately 0.25 gallon per square yard. The exact application rate shall be as recommended by the geotextile manufacturer, and at a temperature of 300 to 350 °F . Paving geotextile shall be applied, per the manufacturer’s recommendations, immediately after the application of asphalt cement binder. Construction equipment, including dump trucks, shall not make sudden stops or starts or sharp turning movements on the geotextile. Dump trucks shall not park on the geotextile before dumping into the asphalt paver. Traffic shall be kept off all newly placed binder and geotextile material until the asphalt surface has been placed. The minimum temperature of the hot mix asphalt at the time compaction begins shall be 250 ° F. 420.05 420-2 The Contractor shall make arrangements with the geotextile supplier to have a technician, skilled in this paving geotextile work, present at the project site during this work to give any technical assistance needed.

420.05 Impervious Lining . Geomembranes for lining shall be loosely laid (not stretched) to

avoid any rupture of the lining. If field lap joints are necessary, the joints shall be formed by lapping the edges of panels per the manufacturer’s recommendations. The contact surfaces of the panels shall be cleaned to remove all dirt, dust, and other foreign materials. Sufficient cold -applied vinyl to vinyl bonding adhesive shall be applied to the contact surfaces in the joint ar ea and the two surfaces pressed together immediately. Wrinkle s in the joints shall be smoothed out. Necessary repairs to the geomembrane shall be patched using the geomembrane material itself and cold -applied vinyl to vinyl bonding adhesive. The bonding adhesive shall be applied to the contact surfaces of both the patch and the lining to be repaired and the two surfaces pressed together immediately. Any wrinkles in the repair joints shall be smoothed out.

420.06 Erosion Control and Drainage . Geotextiles for erosion control or drainage shall be

loosely laid (not stretched) with the roll direction the same as the anticipated water flow, and in a manner that avoids any rupture of the cloth. The geotextile may be anchored in place with securing pins at 3 -foot spacing along but not closer than 2 inches to all edges and to the extent necessary to prevent displacement. When shown on the plans, erosion control geotextile may be held in place using 6 inches of clean embankment with a minimum 6 -inch trench at the top of the slope. Overlaps shall be at least 12 inches on slopes 3:1 and flatter, and at least 24 inches on slopes steeper than 3:1. Laps shall be made with the uphill layer on top. Sewn seams per the manufacturer’s recommendations may be used in place of overlaps. Full rolls shall be used whenever possible in order to minimize the number of roll end laps. Lengths and widths of individual sheets shall be at the Contractor’s option.

420.07 Geotextile Separator . The geotextile shall be unrolled as smoothly as possible on

the prepared subgrade in the direction of construction traffic. The geotextile shall be placed by machinery or by hand labor. The geotextile shall not be dragged across the subgrade. Wrinkles and folds in the geotextile (not associated with roadway curv es) shall be removed by stretching and staking as required. The geotextile may be held in place before placement of cover by pins, staples or piles of fill or rock. On curves, the geotextile may be folded to conform to the curve. The fold or overlap shall be in the direction of construction and held in place as prescribed above. Adjacent geotextile roll s shall be overlapped in the direction of subbase placement using the guidelines in Table 420 -1. Before covering, the condition of the geotextile will be inspected by the Engineer to determine that no holes, rips or other defects exist. If any defects ar e observed, the section of the geotextile containing the defect shall be repaired by placing a new layer of geotextile extending beyond the defect in all directions a minimum distance equal to the overlap shown in Table 420 -1. Alternatively, the defective section may be replaced. Either sewn seams or overlaps (unsewn seams) shall be used in construction. The widths of the overlaps shall conform to Table 420 -1. Sewn seams shall be per the manufacturer’s recommendations. 420.08 420-3 The first lift of cover material shall be end -dumped or spread over the geotextile from the edges of the geotextile. The height of the dumped pile shall be limited to avoid local bearing capacity failures. The first lift of cover material shall be graded to a 12 -inch thickness or to top of grade whichever is less and compacted. Equipment shall not be on the treated area with less than the minimum thickness of compacted cover material over the geotextile. Small dozer equipment or front -end loader shall b e used to spread the cover material. Construction vehicles shall be limited in size and weight such that rutting in the initial lift is no deeper than 3 inches. If rut depths exceed 3 inches, the Contractor shall use a smaller size and weight of construction vehicles. Ruts shall be filled in with cover material. Compaction of lifts shall be accomplished without damaging the geotextile. Construction equipment shall not make turns on the first lift of cover material. Table 420 -1 MINIMUM REQUIRED OVERLAP Subgrade Strength R-Value Overlap Width (Unsewn Seam) Inches 5 – 10 30 10 – 20 24 >20 18

420.08 Landscape Weed Barrier . Landscaped and mulched areas to be covered by geotextile

shall be brought to finish grade below the depth of the mulch material shown on the plans. All soil preparation shall be completed before geotextile application. Geotextile for landscape weed barrier shall be a minimum Class 3, conforming to subsection 712.08. The geotextile shall be rolled directly onto prepared soil in the direction of water flow. The geotextile shall be applied loosely without stretching. The top edge of the geotextile shall be buried in a 6- inch check slot at the top of the slope and stapled. When specified, metal landscape border shall be placed adjacent to check slot on the uphill side, so as not to puncture the geotextile. Where one roll of geotextile ends and a second roll begins, the upslope piece shall be brought over the start of the second roll and overlapped per the manufacturer’s recommendation. Where two or more widths of geotextile are applied side by side, they shall be overlapped per the manufacturer’s recommendation. Staples shall be inserted at a 2 -foot spacing along the outer edges of the geotextile where a metal border is not used. In level planting beds, geotextile shall be secured under metal landscape border by extending the geotextile 6 inches beyond the metal landscape border and driving stakes through the geotextile. 420.09 420-4 METHOD OF MEASUREMENT

420.09 Geomembranes and geotextiles will be measured by the square yard of surface

area covered, complete in place. BASIS OF PAYMENT

420.10 The accepted quantities will be paid for at the contract unit price for each of the

pay items listed below that appear in the bid schedule. Payment will be made under: Pay Item Pay Unit Geomembrane Square Yard Geotextile (Erosion Control) (Class ) Square Yard Geotextile (Drainage) (Class ) Square Yard Geotextile (Weed Barrier) Square Yard Geotextile (Paving) Square Yard Geotextile (S eparator) (Class ) Square Yard Securing pins, staples, adhesives, sewn seams, asphalt cemen t, brooming, skilled technician, and other work and materials necessary for placement will not be measured and paid for separately but shall be included in the work. 501.01 501-1 DIVISION 500 STRUCTURES SECTI ON 501 STEEL SHEET PILING DESCRIPTION

501.01 This work consists of furnishing and driving corrugated steel sheeting or steel sheet

piling per these specifications and in conformity to the lines and grades shown on the plans or established. MATERIALS

501.02 Type I Steel Sheet Piling shall be used where shown on the plans and shall be a

corrugated steel sheeting non- galvanized interlocking type, at least 8 gauge in thickness with a minimum section modulus of 1.300 cubic inches per unit of 12 inches in width. Steel sheeting shall confo rm to ASTM A857, Grade 36 for 7 gauge or 8 -gauge steel, Grade 30 for heavier gauges. The sides for each piece of sheeting shall be furnished with an interlock that is continuous for the full length of the sheeting. The interlock shall have an opening of sufficient width to allow free slippage of the adjoining sheet.

501.03 Type II Steel Sheet Piling shall be of the type and weight shown on the plans and shall

conform to the requirements of AASHTO M 202 or AASHTO M 270, Grade 50. CONSTRUCTION REQUIREMENTS

501.04 Steel sheet piling shall be driven to form a tight bulkhead. A driving head shall be used

and any piling that does not provide a tight bulkhead shall be pulled and replaced at the Contractor's expense. Steel sheet piling that is full length as shown on the plans and is required to be driven below the specified cut -off elevation shall be spliced with additional steel sheet piling with a full penetration butt weld. Splicing will be limited to three per pil e sheet. A splice shall not be less than 3 feet from another splice on the same pile. Welding shall conform to the applicable requirements of ANSI/AWS D 1.1. Where specified on the plans, sheet piling shall be painted as described in subsection 509.24. METHOD OF MEASUREMENT

501.05 Steel sheet piling will be measured by the square foot, complete in place and accepted,

to cut -off elevation. Each approved splice will be measured as an additional 3 square feet of sheet pile. The area of sheet piling cut -off to be measured will be those random areas of sheet piling that result from cutting off the tops of driven sheet piling and not used in the work.