Deteriorating manholes: to repair, restore or replace? And how? At what cost?These nettlesome questions face many municipal sewer system managers, especially in older cities where infrastructure is long in the tooth.One method of manhole restoration is to fit a plastic conical form inside the existing structure and pour a concrete liner around it — essentially providing a new manhole wall. The concrete restores the structural integrity of the manhole while forming a seamless barrier against future infiltration and inflow. Infrastructure Technologies Inc. (Infratech) of Rogers, Minn., markets and installs the technology known as the Monoform manhole liner-forming system. The procedure
