Washwater Tank Seismic Improvements

STI/SPFA 2023 TANK OF THE YEAR Product Award

Product /Project Title: Washwater Tank Seismic Improvements
Product Owner: Santa Fe Irrigation District
Product Location: Rancho Santa Fe, CA
Date Completed: January-2023
Overall Height or Length: 80’
Diameter (feet/inches): 46’
Capacity (gallons): 950,000
Steel Tonnage Used: 25
Steel Thickness (inches): 1.5″
Product/Project Description:
This project consists of the Seismic Improvements to Washwater Tank. The project included new tank foundation, new anchor chairs, new tank shell stiffeners, repairing existing rafters, new mesh screen to overflow, modifying existing external inlet/outlet piping, provide new gasket to existing roof manway, remove existing center roof vent and install new center roof vent, provide new fall prevention system to existing interior ladder, provide new toe-boards for existing stairway, provide new tether points, and providing new patch plates for holes or pitted areas.
Even though the tank had been in service for 40+ years with no issues, a structural evaluation was done and determined that the foundation was severely undersized. Most contractors bid this job to install piles and pour a matte foundation under the tank in sections with it still in place. But with some careful planning and engineering, we were able to come up with a plan to move the entire tank 200′ off the existing pad. This specific situation is unique due to the fact that this a standpipe opposed to a flatbottom reservoir.

No other tank construction has the flexibility or material characteristics to allow this move which exemplifies the beauty of steel.

RELATED WORK