Warsaw, N.Y. Wastewater Treatment Plant Expansion

Challenge: Construction of the new clarifier for the plant expansion required excavation support in soft soils. Typically the circular cofferdam would be supported by steel beams bent along the strong axis. The large diameter of the hole would require heavy steel beams bent off site at a high cost.

Solutions: The circular excavation plan provided that all the walers would be in pure compression, a perfect working solution for concrete. Design of the concrete walers included reinforcing for handling and connection stresses. A true level of economy resulted from fabrication of the sections at the project site, which included reuse of wooden forms and elimination of transportation.

Results: Fabrication controls resulted in perfect circles and an exact fit between components. Once the excavation was complete and the new clarifier constructed, the cofferdam was dismantled. Unlike steel walers that would be bent to the specifics for this project and hence of no value for future work, the concrete sections were repurposed as retaining wall materials, adding another level of cost savings for the contractor.