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Alpine Construction, LLC 10 Broad Street

Schuylerville, New York 12871 (518) 695-6739

[email protected]

Dam & Hydroelectric Experience Photographs

Alpine Construction, LLC

Nassau Lake Dam Project

Project: Construction of New Gravity Dam with Integral Low Level Outlet

Description / Highlights

• Dam foundation incorporates a permanent sheet pile structure which acts as cofferdam and cutoff wall along the upstream face of dam to reduce seepage under dam structure.

• Select structural fill contoured to design shapes

• Reinforced concrete gravity dam with energy dissipation basin

• Construct 2-acre wetlands area to offset wetlands areas affected by the construction of the new dam.


Permanent Sheet Pile Cofferdam – Frame Supported


Select Structural Fill Contoured to Design Shapes


Reinforcing Steel Installation of Downstream Energy Dissipation Basin


Completed Dam, Energy Dissipation Basin and Abutment with Low Level Outlet Structure


Middle Falls Hydroelectric Project

Project: Intake Canal Wall Rehabilitation


• Design Build Contract with Owner

• Assist with FERC and NYSDEC permitting.

• Cofferdam design concept which allowed operation of the facility during rehabilitation of canal wall.

• Demolition of existing stone masonry and concrete dam.

• Reinforced concrete gravity structure.

• Trash and ice sluice incorporated into the new canal wall section.


Existing Canal Wall Failure


Sheet Pile Cofferdam Strut Supported


Canal Wall Construction


Ice / Trash Sluice Construction


Completed Canal Wall with Integral Sluice Gate


Fourth Branch Hydro Electric Project

Project: Intake Canal Wall Rehabilitation


• Design Build Contract with Owner.


• Permanent sheet pile cofferdam design concept which allowed operation of the facility during rehabilitation of canal wall.

• Select demolition of existing stone masonry and concrete dam.

• Concrete gravity structure.


Existing Canal Wall Failure


Sheet Pile Cofferdam – H-Pile Supported – Design Concept


Sheet Pile Cofferdam –Drill H-Pile Supported


Dewater and Bedrock Clean Preparation


Formwork and Reinforcing Steel


Completed Wall Section


Sissonville Hydroelectric Project

Project: Intake Deck Replacement




• Design concept that did not require complete dewatering of the intake during construction and allowed select operation during non-critical phases of work.

• Demolition of composite concrete and structural steel intake deck.

• Construction of new reinforced concrete deck with stay in place structural steel shoring system.

• Stability of reinforced concrete deck independent of the structural steel shoring system.


Select Pier Demolition


Stay in Place Form / Armoring


Structural Steel Framing for Deck Shoring / Support


Reinforcing Steel Installation with Embeds for Future Trashrake


Complete Concrete Intake with Crane Rails for Future Trashrake


Middle Falls Hydroelectric Project

Project: Dam Rehabilitation




• Select demolition of the abutment and dam.

• Construction of new reinforced concrete dam.

• Installation of post tension anchors.

• Installation of rubber dam


Existing Conditions Dam with Flashboards


Rehabilitation with Rubber Dam


North Abutment Construction


Dam Monolith Construction


Dam Outfitted with Rubber Dam


Geyser Pond Dam

Project: Upstream Cutoff Wall at the Base of the Existing Dam


• During construction of the new abutment it was determined that the dam was founded on glacial till that which was causing excessive uplift on the dam.

• Design cofferdam to facilitate phased dewatering of the upstream face of dam.

• Select demolition of timber crib, masonry and glacial till to bedrock.

• Installation of upstream cutoff wall that reduced flow under the dam thereby significantly reducing uplift.


Cofferdam Design to Facilitate Upstream Cutoff Wall Construction


Installation of Sheet Pile around Support Frame


Cofferdam Dewatered with Upstream Cutoff Complete

alpine construction, llc€¢dam foundation incorporates a permanent sheet pile structure which acts...

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