The Upper Collinsville Dam is located along the Farmington River in the Town of Canton, CT. The dam was constructed in 1867 by the Collins Company to power their facilities. The re-development of the dam was started in 2015 for the Town with Canton Hydro, LLC as the project’s developer and WWS Wasserkraft as the turn-key solution provider.
Tectonic Engineering Consultants, Geologists & Land Surveyors, D.P.C., Inc. (Tectonic) was retained to provide reinforced concrete structural engineering as the design-build process proceeded in 2018. This work entailed final design of walls, floors, foundations, beams, columns, piers and other concrete structures related to the modifications of the dam and historic building to accommodate the new mechanical systems. As the project progressed, Tectonic‘s engineering role on the project greatly expanded and Tectonic assumed the Engineer of Record role as mandated by the Federal Energy Regulatory Commission (FERC). Tectonic directly coordinated with FERC to obtain the overall design approval from FERC for construction, prepared stability analysis and improvement for the dam and powerhouse structures, geotechnical engineering, prepared a detailed quality control program for approval by FERC, and provided construction oversight, vibration monitoring, testing and inspection as the construction work progressed.
Tectonic also provided direct coordination with the Town of Canton, Connecticut Department of Energy and Environmental Protection, Connecticut Department of Transportation, Eversource, FERC, Wasserkraft (WWS) and Canton Hydro LLC. Major structures designed by Tectonic include (not limited to): dam modifications with new concrete columns and slabs added to the top of the existing dam, new rock anchors for the dam, reinforced concrete walls and foundation slabs for fishway passage, reinforced concrete columns and beams for the new steel intake gates and the trash rack wall, powerhouse building modifications with new reinforced concrete floor slab for the new turbine equipment, reinforced concrete slab bridge for vehicular access to the building, mass reinforced concrete beam at the intake, concrete spiral to the turbine and concrete draft tube outlet, new one-story fish monitoring building, concrete pad and retaining wall for the new transformer. All designs were performed following the Federal Energy Regulatory Commission (FERC) Engineering Guidelines, AASHTO LRFD, ACI-318, ACI-350 (for under water concrete), ASIC Steel Manual, and FHWA-IF-99.
The major challenges Tectonic faced and resolved include:
- Designed concrete structures with very irregular geometry.
- As a design-build project, Tectonic finished different portions of the design in a timely manner and obtained approvals for construction to accommodate the on-going construction schedule.
- Provided practical and economical design while making sure design conformed with FERC guidelines.
- Coordinated between multiple parties: FERC, the developer Canton Hydro, LLC, the turn-key solution provider WWS, and the Contractor.
- Incorporated the unusual design forces and geometry of the special steel mechanical components designed by WWS, including the hydraulic piston-controlled crest gates, the turbine and generator at the power house slab, and the draft tube under the turbine.
- Provided full engineering review of WWS calculations and engineering drawings for structural steel, hydraulic gates, and other civil works.
- Provided timely field design changes to accommodate site geometry constraints and contractor‘s means and methods.
