292 ALASKA 2020 SECTION 605
605-1.01 DESCRIPTION . Construct underdrains and blind drains, underdrain outlets, cleanouts,
and marker posts.
605-2.01 MATERIALS. Use materials that conform to the following:
Porous Backfill Material Subsection 703- 2.10 Perforated Concrete Pipe Subsection 706- 2.03 Perforated PVC Pipe Subsection 706- 2.06 Perforated Corrugated Polyethylene Pipe Subsection 706- 2.07 Corrugated Steel Pipe Subsection 707- 2.01 Bituminous Coated Corrugated Steel Pipe Subsection 707- 2.02 Corrugated Aluminum Pipe Subsection 707- 2.03 Gray Iron Casting Subsection 719-2.02 Marker Post Subsection 730- 2.05 CONSTRUCTION REQUIREMENTS
605-3.01 PIPE INSTAL LATION. Excavate trenches to the dimensions and grade required by the
Plans or as directed. Place and compact a 3- inch minimum bedding layer of porous backfill material in the bottom of the trench for its full width and length. Use coupling bands for 6 inch, 8 inch, and 10 inch diameter corrugated underdrain that are 2 piece, 7 inch minimum width and corrugated to match the corrugations of the pipe. Place perforated pipe with the perforations down. Join pipe end sections securely with the appropriate coupling fittings or bands. Plug or cap up- grade ends of subdrain pipe to prevent entry of soil materials. After the pipe installation has been inspected and approved, plac e porous backfill material to a height of 12 inches above the top of pipe. Place and compact the remainder of the porous backfill material as specified in Section 204, to the required height. Fill trench above the porous backfill with specified material.
605-3.02 UNDERDRAIN OUTLETS. Excavate trenches for underdrain outlets to the width and
depth shown on the Plans. Lay pipe in the trench with ends firmly joined. Backfill the trench after inspection and approval of the pipe installation.
605-3.03 BLIND DRA INS. Excavate trenches for blind drains to the width and depth shown on
the Plans. Fill the trench with specified backfill materials to the depths required by the Plans. Compact all backfill material.
605-4.01 METHOD OF M EASUREMENT. See Section 109 and as follows:
Underdrains, including outlets, and blind drains are measured along the invert. Porous backfill material is measured by calculated volume, using Plan dimensions for trench width, depth, and measured invert length of perforated pipe.
605-5.01 BAS IS OF PAYMENT. When not listed in the bid schedule, porous backfill material is
subsidiary. Pipe cleanouts, including the cast iron cover and marker post are subsidiary. Excavation is paid for under Section 204. 293 ALASKA 2020 Payment will be made under: PAY ITEM Item Number Item Description Unit 605.0001.____ Perforated Corrugated Steel Pipe for Underdrain ___ Inch LF 605.0002.____ Perforated Corrugated Aluminum Pipe for Underdrain ___ Inch LF 605.0003.____ Perforated Pipe Underdrain ___ Inch LF 605.0004.____ Blind Drain LF 605.0005.____ Porous Backfill Material CY 605.0006.____ Perforated Corrugated Polyethylene Pipe for Underdrain ___ Inch LF 605.0007.____ Perforated PVC Pipe for Underdrain ___ Inch LF 294 ALASKA 2020 SECTION 606 GUARDRAIL
606-1.01 DESCRIPTION . Construct new guardrail, terminal sections, and transition rail of the
kind and type specified. Remove and reconstruct or remove and dispose of existing guardrail, terminal sections, and transition rail.
606-2.01 MATERIALS. Use materials that conform to the follow ing:
Concrete Section 550, Class B Flexible Delineator Posts Section 730- 2.05 Guardrail Connection Plate Section 722 Guardrail Hardware Subsection 710- 2.07 Guardrail Posts and Blockouts Subsection 710- 2.06 High Strength Bolts Section 722 Metal Beam Rail Subsection 710- 2.04 Terminals Subsection 710- 2.11 Wire Cable Subsection 709- 2.02 Terminal Markers. Single piece marker, meeting the requirements of Section 730- 2.05 Flexible Delineator Posts. Post-mounted flexible delineators. Single piece marker, meeting the requirements of Section 730- 2.05 Flexible Delineator Posts. Furnish terminal markers, color as shown on the plans, nominally 0.125 by 3.75 inches by 66 inches long or as shown on the plans, with a 3 inch by 12 inch retroreflective sheeting matching the color of the adjacent lane line, or as shown on the plans. Furnish post -mounted flexible delineators with retroreflective sheeting, color and dimensions as shown on the plans. Fabricate side- mounted guardrail reflector assembly brackets from aluminum alloy. Retroreflective sheeting for terminal markers, post -mounted flexible delineators, and side- mounted guardrail reflectors shall meet ASTM D4956 requirements for Type VIII, IX, or XI.) CONSTRUCTION REQUIREMENTS
606-3.01 GENERAL. Install guardrail a nd terminals at the locations shown on the Plans. Conform
with the Alaska Standard Plans and these Specifications. At locations where public traffic is adjacent to guardrail work, have all materials on site, including crashworthy terminals, that are requir ed to completely install a segment of guardrail before beginning work on that segment. Start guardrail installation at the “upstream” end (the end adjacent traffic will encounter first) by either installing a crashworthy terminal or connecting to an existi ng barrier. Continue installation in the direction of traffic. Exception: if the guardrail run will connect to existing barrier, buried in the backslope, or guardrail, existing or new bridge railing, or other existing structure at the “downstream” end, guardrail installation may be started at the point of connection. Do not leave posts installed for guardrail within the clear zone for more than 48 hours before installing the rail. At the end of each work shift, install drums or Type II barricades with flashing warning lights to delineate incomplete sections of guardrail and terminal sections.