Piermont Bridge: A Historic Link Between New Hampshire and Vermont
Spanning the Connecticut River, the Piermont Bridge serves as a vital transportation link connecting Piermont, New Hampshire, and Bradford, Vermont. More than just a crossing for New Hampshire Route 25 and Vermont Route 25, this structure is a testament to early 20th-century engineering and resilience in the face of natural disasters.
Key Facts
- Location: Spans the Connecticut River at the New Hampshire-Vermont state line.
- Construction Year: 1928.
- Architectural Style: Pennsylvania through truss.
- NRHP Status: Listed on the National Register of Historic Places since June 6, 2001.
- Ownership: Jointly owned by New Hampshire (90%) and Vermont (10%).
Engineering and Architectural Design
The Piermont Bridge is a Pennsylvania through truss bridge, a specific type of steel truss design characterized by sub-struts and sub-ties that allow for longer spans than standard Pratt trusses. Built by the Boston Bridge Works in 1928, the bridge features a single span with a clear length of 352 feet and an overall length of 354 feet 10 inches.
The roadbed measures 20 feet 7 inches in width, providing a vertical clearance of 14 feet 7 inches. Positioned approximately 25 feet above the river, the bridge utilizes a mix of materials for its supports. The western abutment in Vermont is constructed from split granite sourced from the nearby Fairlee Mountain. In contrast, the eastern abutment is an early example of structural concrete, originally built in 1908 by John Storrs for a previous bridge.
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A History of Resilience
The current structure was born out of necessity following the devastating rains and flooding of 1927. These floods caused widespread damage across Vermont and washed away several bridges along the Connecticut River. The Piermont Bridge was the longest bridge constructed in the aftermath of this disaster.
It replaced a two-span Town lattice truss bridge—a design using a crisscross pattern of planks or beams—that had been in place since 1875. Evidence of this predecessor remains today, as the center pier of the 1875 bridge was knocked down to the waterline and is still visible to observers.
To accommodate the heavier weight of the 1928 steel structure, the existing 1908 concrete eastern abutment was strengthened. Engineers added new concrete to the land side of the abutment, a method that reinforced the structure while preserving the original early-concrete work.
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Modern Preservation and Specifications
To ensure the bridge remained functional for modern traffic, it underwent a major renovation in 1993. This project included the replacement of much of the bridge decking and the addition of a sidewalk, which also served as a conduit for utility lines.
| Feature | Detail |
|---|---|
| Total Length | 354' 10" |
| Clear Span | 352' |
| Roadbed Width | 20' 7" |
| Vertical Clearance | 14' 7" |
| Height Above River | Approx. 25' |
| NRHP Reference No. | 01000630 |
Frequently Asked Questions
Why is the Piermont Bridge historically significant?
The bridge is significant for its Pennsylvania through truss design and its role as the longest bridge rebuilt following the catastrophic 1927 Connecticut River floods. It is officially recognized on the National Register of Historic Places.
Who owns and maintains the bridge?
The bridge is owned jointly by the states of New Hampshire and Vermont, with New Hampshire holding a 90% ownership stake and Vermont holding 10%.
What materials were used for the bridge abutments?
The western abutment is made of split granite from Fairlee Mountain, while the eastern abutment consists of structural concrete dating back to 1908.
What happened to the bridge that existed before 1928?
The previous bridge was a Town lattice truss structure built in 1875. It was replaced after the 1927 floods, though its center pier remains visible at the waterline.
When was the bridge last renovated?
The bridge underwent a major renovation in 1993, which included updating the decking and adding a sidewalk for pedestrians and utilities.