Draft Infiltration and Inflow Report March 1998

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07 - Install Manhole Frame and Cover - Raise Manhole to Grade A broken or damaged manhole frame can become an inflow source and a safety hazard. This rehabilitation method addresses installation of a new frame and cover on an existing manhole located in an area subject to inundation or heavy runof£ Additionally the manhole cover needs to be raised to grade as described in rehabilitation code 08 below. 08 - Raise Manhole to Grade Due to re-paving, settlement, and grade changes, a manhole may be covered or become subject to inundation. The solution is to raise the manhole to the grade of the surrounding area. In a paved area, this entails removing pavement to gain access, excavation to expose the frame to chimney or frame to cone connection, and removal of the frame. Then vertical spacers are inserted, waterproofed on the exterior, and the frame is re-installed and sealed, followed by backfilling and pavement replacement. In cases where the manhole is a foot or more below grade, it may be necessary to add a chimney above the existing cone or to remove the cone, construct an addition to the wall, re-install the cone, and follow the steps detailed above. 09 - Realign and Seal Manhole Frame Cementitious materials are normally used to seal a frame to the top of the manhole cone or chimney. This seal can become damaged and, in severe cases, the frame can be offset from the manhole. In a paved azea, rehabilitation entails removing pavement to gain access, excavation to expose the frame to chimney or frame to cone connection, and removal of the frame. The frame is realigned and sealed, followed by backfilling and pavement replacement. 10 - Repair Leak at Manhole Lid Adjuster Various types of adjusters may be used to raise or level a manhole frame. This rehabilitation method addresses realignment and re-sealing around the defective adjuster. ADS Enviroamental Services, Inc. VI-10