Fort Miller Precast provided a custom precast structure package of HVDC splice vault systems for the Champlain Hudson Power Express project.

Project Details

• Owner: CHPE/Transmission Developers
• Contractor: Kiewit Power Construction
• Project Completion: 2026
• Scope: 3,000+ precast components (vault segments, tubs, lids/roof slabs)

Project Overview

Champlain Hudson Power Express (CHPE) is a 350-mile high-voltage direct current transmission project designed to deliver renewable power into New York City. As the largest fully buried transmission line in the U.S., the largely underwater/underground transmission line will offer cross-border interconnection to Hydro-Québec.

CHPE’s lines transition between submerged cable runs, shoreline landings, and buried terrestrial installations. For improved longevity, the contractor opted to utilize precast concrete cable vaults to house cable joints, terminations, and access panels for inspection and maintenance over the asset life.

Over a two-year production effort, Fort Miller’s engineering and manufacturing teams executed a custom precast structure solution, purpose-built around performance, constructability, and field assembly requirements. 

Scope and Details

Fort Miller Precast designed and fabricated 65 precast concrete segmental Splice Vaults, cast in seven segmental sections per vault. We also fabricated 170 precast concrete Tubs with separate precast roof slabs.

The segmental strategy was executed to support predictable handling and staging while preserving alignment, consistent joint interfaces, and repeatable field assembly conditions.

Staging capacity at the Easton facility allowed complete components to be delivered in the order required for installation and closure.

By shifting much of the structure fabrication and quality control to the plant, field work at each location was reduced, eliminating extended formwork, rebar placement, and concrete cure time typical of cast-in-place construction. 

This helped limit the noise, local access constraints, and duration of open excavations, an important advantage on a project executed across multiple municipalities

Impact and Innovation

For buried HVDC transmission systems, transition and splice locations concentrate technical risk. They integrate cable handling, jointing, and long-term accessibility, all within a constrained footprint. 

By supplying segmental underground precast structures at scale, Fort Miller helped reduce reliance on time-intensive cast-in-place construction at these critical points while enabling standardized installation workflows along a long, variable corridor.

Fabrication in a controlled plant environment supported dimensional repeatability and consistent enclosure geometry, improving fit-up reliability during field assembly and supporting serviceability requirements inherent to underground splice vault applications. 

In parallel, staging and just-in-time delivery capabilities helped align component availability with field progress, limiting on-site laydown needs and reducing schedule exposure tied to constrained access and variable production windows. 

As CHPE advances delivery of renewable power into New York City through the Astoria converter station, Fort Miller’s custom precast structure package continues to provide durable, access-ready infrastructure that protects cable splices and terminations at the project’s most sensitive transition points.