Client: Grant County Public Utility District
Location: Grant County, WA
Service Provided: Construction Inspection
In early 2014, during routine Tainter gate operation testing and maintenance, one of the chains used to lift and lower the gates at the Wanapum Dam failed. After further inspections it was determined that 18 chains for the twelve spillway gates required refurbishment due to aging chain pins.
The work required refurbishment of eighteen Tainter gate chains including chain removal, removal and replacement of all pins and zerks (over 3,300 in total), thorough cleaning, touch up painting of the existing zinc coating, regreasing, and placing the chain back on the appropriate gate hoist. Protection of the chains during removal and refurbishment was critical to prevent damage. The chains had extensive amounts of grease that required removal and replacement, which made environmental protections extremely important to prevent contamination of the river and spillway deck.
Grant County PUD entrusted MacKay Sposito to provide construction inspection for the work. Our inspector closely documented the work, tracking all labor, equipment, and materials and ensuring conformance with the drawings and specifications. For instance, during pin replacement on the initial chain, our inspector identified pin defects. Catching the issue early allowed the project to remain on schedule. We also flexed our inspection time with other projects in the area to minimize costs.