Upper Collinsville Dam

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.

New NY Bridge (Tappan Zee Bridge Replacement)

Tectonic is providing inspection and testing services as a subconsultant to the design build team for the construction of the New NY Bridge, formerly known as the Tappan Zee Bridge. The existing bridge is an essential component of the regional roadway network connecting Rockland and Westchester counties and provides integral access to the New York Metropolitan Area.

The services Tectonic is providing are guided by the Quality Assurance and Quality Control program for the project, which was developed using ISO 9001 standards, 23 CFR Part 637 requirements and the project’s contract document. Tectonic is responsible for all components of special inspections and materials testing, including:

  • Pile driving inspection & monitoring
  • Steel inspection & non-destructive testing of steel components
  • Geotechnical inspection of earthwork, subgrades & backfill
  • CIP & precast concrete inspection & testing
  • Asphalt paving inspection & testing
  • Establishment of an on-site materials testing laboratory

The new NY Bridge is designed for a 100-year service life and will be mass-transit-ready. It will feature twin 3-mile structures, each with 1,200-foot cable-stayed main spans and 350-foot steel girder approach spans. The Bridge will provide 8 general traffic lanes, emergency lanes, extra-wide shoulders for express bus service, a dedicated bicycle and pedestrian path on the northern span, and scenic overlooks with anti-climb fencing and security cameras. A new toll plaza will include at least 3 highway-speed E-Z Pass lanes.