6-18
604.23 Step Each
604.242 Catch Basin Type F3 Each 604.243 Catch Basin Type F3-C Each 604.244 Catch Basin Type F4 Each 604.245 Catch Basin Type F4-C Each 604.246 Catch Basin Type F5 Each 604.247 Catch Basin Type F5-C Each 604.248 Catch Basin Type F6 Each 604.249 Catch Basin Type F6-C Each
604.25 Catch Basin Type A5 Each
604.252 Catch Basin Type A5-C Each
604.26 Catch Basin Type B5 Each
604.262 Catch Basin Type B5-C Each SECTION 605 - UNDERDRAINS
605.01 Description This work shall consist of the construction of underdrain, using
pipe and filter material and pipe outlets in accordance with th ese specifications and the standard detail plans and in reasonably close conformity with t he lines and grades shown on the plans or established.
605.02 Materials. Materials shall meet the requirements specifi ed in the following
Sections of Division 700 - Materials: G r a n u l a r B o r r o w 703.19 Underdrain Backfill Material 703.22 Underdrain Pipe C o r r u g a t e d P o l y e t h y l e n e P i p e 706.06 P o l y v i n y l c h l o r i d e ( P V C ) P e r f o r a t e d P i p e 706.09 Corrugated Steel, Metallic Coated Pipe for Underdrain 707.05 Corrugated Aluminum Alloy Pipe for Underdrain 707.08 Underdrain Outlet Pipe C o r r u g a t e d P o l y e t h y l e n e P i p e 706.06 Corrugated Steel, Metallic Coated Pipe for Underdrain 707.02 Corrugated Aluminum Alloy Pipe 707.06 Connections for polyethylene pipe shall be made with external wrap-around split couplings, screw-on type couplings, external snap-on couplings, or bell and spigot and ring gasket. External wrap-around split couplings shall be secured with heavy duty splicing tape or plastic or wire ties placed on each side of the coupling. E xternal snap-on couplings shall comply with the appropriate sec tion of AASHTO Specifications. 6-19 Connections for other plastic underdrain pipe shall be made wit h bell and spigot and ring gasket. Connections for metallic underdrain pipe shall be made with co rrugated metal bands secured with bolts. Dimpled bands shall not be used. Other types of connectors for underdrain may be used upon appr oval by the Resident. 605.021 Fittings The material for elbows, tees and wyes for Un derdrain pipe shall be at least as thick as the largest size pipe being connected.
605.03 General Underdrain pipe for Underdrain, Type B shall, at the Contractor's
option, consist of any one of the following types: Corrugated Aluminum Alloy Pipe for Underdrain Corrugated Polyethylene Pipe for Underdrain (Smoothlined) Metallic Coated (Zinc or Aluminum Coated) Corrugated Steel Pipe for Underdrain Polyvinylchloride (PVC) Perforated Pipe At the Contractor's option, underdrain pipe for Underdrain Typ e C shall consist of any one of the following types: Corrugated Aluminum Alloy Pipe for Underdrain Corrugated Polyethylene Pipe (Smoothlined) Metallic Coated (Zinc or Aluminum Coated) Corrugated Steel Pipe for Under-drain Polyvinylchloride (PVC) Perforated Pipe 605.04 Underdrain Construction
a.Underdrain, Type B The trench shall be excavated to the req uired width and depth and a bed of the specified granul ar material, 3 inches in depth , prepared in the trench. 6 inch perforated pipe shall be laid on t his bed with the perforations as shown on the Standard Detail plans. After the pipe has been firmly bedded and joints securely conne cted, it will be inspected before any backfill is placed. The remaining backfill shall be granular material meeting the same requirements as that used for bedding the pipe. For underdrain placed under areas of proposed pavement, the mat erial shall be placed in 8 inch layers, loose measure and thoroughly compacted except th at the initial layer of backfill around the pipe may be placed in a layer not exceeding 12 inches. For underdrains placed under areas not proposed to be paved, the initial layer of backfill shall not exceed 12 inches and the remaining material may be placed in one lift to the elevation of the subgrade and compacted with heavy rubber tired or vibratory compaction e quipment to the satisfaction of the Resident. 6-20 The upstream end of all completed underdrain pipe shall be seal ed with cement mortar or other acceptable material. Care shall be taken that soil do es not enter the pipe. Pipe contaminated before backfilling shall be removed, cleaned, and re-laid.
b.Underdrain Type C The trench shall be excavated to the widt h and depth as determined by the size and depth of the pipe to be installed. The perforated pipe shall be laid to line and grade centered on the bottom of the trench with the perforations as shown on the Standard Detail plans. After the pipe has been firmly bedded and all joints securely c onnected, it will be inspected before any backfill is placed. The backfill shall be placed in accordance with Section 603.08 and as shown on the Standard Detail plans using the materials specified. When Underdrain Type B or Underdrain Type C is constructed, ba ckfill material beyond the underdrain trench lateral limits designated on the p lans shall be material conforming to the requirements of Granular Borrow, Underwater B ackfill. Material within the underdrain trench limits shall conform to the requirements of the type underdrain being constructed. The Contractor shall take precautions to prevent the underdrain backfill material from becoming contaminated with clay, silts, organic m atter, or other foreign matter. Methods of placing backfill material shall be limited to the use of equipment that will place material directly into the trench. Pushing material into the trench will not be allowed. When underdrain is to be constructed in embankment fill, the e xcavation for the trench shall be done after the embankment has been completed to subgrade elevation.
605.05 Underdrain Outlets Trenches for underdrain outlets sha ll be excavated to the
required width and depth. These outlets shall be of the same s ize and wall thickness used in the underdrain, except that the perforations may be omitted. The pipe shall be laid in the t rench with all ends firmly joine d by the applicable methods and means. After inspection and approval of the pipe installat ion, the trench shall be backfilled with suitable material in layers and compacted as pr ovided for in Section 603.08.
605.06 Method of Measurement Underdrain and underdrain outlets will be measured by
the length in linear feet along the centerline of underdrains a nd underdrain outlets of the types and sizes completed and accepted. When elbows, tees, wyes, or other special fittings are require d in underdrain, each fitting shall be included for payment as 3 additional linear fe et of the largest pipe size involved.
605.07 Basis of Payment The accepted quantities of underdrains and underdrain outlets
will be paid for at the contract unit price per linear foot of each type and size specified
Source: Maine Standard Specifications for Road and Bridge Construction, 2020 Edition. Pages 488–490 of 817.
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