Internal Repairs of Concrete Conduits at Cleveland

At Cleveland, Ohio's Division Filter Plant, a two‐duct concrete conduit 600 ft long conveys water from the filters to the reservoir. This conduit, which is 12 ft underground and 9 ft below lake level, had been in continuous service for more than 40 years when it was found to be leaking at a rate of several million gallons daily. During past years numerous repairs had been made on the outside of the conduit. The idea of making internal repairs seemed absolutely impossible as it was conjectured that so much water was leaking through the 12‐in. concrete dividing wall separating the two conduits that draining would be impossible; moreover, one conduit had to remain in service to supply the west side of the city with water while the other was being repaired. The capacity of each conduit is 110 mgd and the demand at the plant does not fall to less than that quantity until midwinter. The article presents the findings of a preliminary inspection, and based on this report permanent repairs to both conduits were recommended. Dewatering of the conduits is described, along with repair methods. Repairs of the north conduit were completed in one third the time required for repairing the south conduit, because no water was seeping from the south to the north conduit. Work was completed at 8 per cent of the estimated $1,000,000 cost of new conduits.