922 PREFABRICATED EDGE DRAINS
From MDOT Policy Manual
- The manufacturer shall furnish certification as specified in TC-1.03.
922.02 PREFABRICATED EDGE DRAINS.
- Shall be flexible, rectangular conduit consisting of supporting drainage core encased in a geotextile.
- Drainage Core. Material shall be manufactured from polymers having a high resistance to deterioration by pavement deicing salts, petroleum based materials, and naturally occurring soil chemicals. The core shall have sufficient flexibility to withstand bending and handling without damage or significant weakening.
- The core geotextile contact point spacing for post and cuspated sheet type cores shall not exceed 1.125 in. Elongated pipe core sections shall have a 7.5 in./ft minimum open area to allow lateral flow into the core. Cores with support on only one side shall have a minimum of 5 percent of the area of that support side in unobstructed flow. Drainage core shall meet the following requirements:
TEST PROPERTY TEST
Thickness, in. min — 0.75 Compressive Strength, psi, @ 20% maximum deformation, min (a) 40 In-plane Flow Rate, gal/min/ft of width, min D 4716 (b) 15
- (a) D 5034 for crushed sheet and post type cores. D 2412 for elongated pipe type cores.
- (b) 10 psi load after 100 hr at a hydraulic gradient of 0.1
- Geotextile Wrap. 921.09, Class SD, Type II.
- The fabric shall be bonded to contact points of supporting core for post and cuspated sheet type cores to ensure that the geotextile does not sag into the core flow area. The geotextile shall be tightly stretched over the core for elongated pipe type cores.
- Fittings for the pavement edge drain systems, including, but not limited to end seals, splices, outlets, and shunts shall meet the manufacturer’s recommendations and be of sufficient strength to withstand construction handling and permanent loading. All fittings shall be as approved.
922.04 OUTLET PIPE.
- Pipe for outlets shall be 6 in. minimum diameter and meet Section 905.