Pump Station S7 and S8

Awarded to Kiewit Southern Co., a subsidiary of Kiewit Corporation, the Pump Stations S7 and S8 project was a $9.5 million rehabilitation project that included the complete removal and rehabilitation of seven 1,100-cubic-foot-per-second and 880-cubic-foot-per-second axial propeller pumps.

The pump rehabilitation included new 16-inch-by-30-foot shafts, mechanically sealed, helical-roller bearings, thrust bearings and bearing housings. The team resurfaced all of the 12-foot-diameter impellers as well as de-leaded, repaired and repainted the pump housings and replaced all housing bolts. They replaced the 1950s vintage chain-drive reduction boxes, installed new engine exhaust systems with 30-inch stainless steel mufflers and a new vacuum primer pump, and laser aligned the engine, gear box and pump shaft within 10 thousandths of an inch. While the pump was out of service, Kiewit repaired and modified each suction basin with cast-in-place concrete vortex suppression walls, pump supports, new bearing pedestals, and relocated the pump basin dewatering system, removed and replaced four 12-foot-by-20-foot stainless steel backflow gates, including rails, actuators and operators.

The scope of work included dismantling the existing 1,100-cubic-foot-per-second and 880-cubic-foot-per-second axial propeller pumps and replacing worn out parts. The team also had to re-machine the propellers and replace bearings, reconfigure the pumps basins, and a telemetry package. The team designed, installed and commissioned four new gantry cranes between a 10- and 35-ton capacity, and replaced the raw water system.