Ridgefield's Bridges: How They Stack Up

RIDGEFIELD, CT — Ridgefield’s bridges are largely in good shape, but one key crossing on the town’s western side received only a “fair” condition rating in recent inspections, according to newly released state transportation data.

A review of CTDOT’s most recent bridge inventory shows that four of the five Ridgefield bridges included in the state database are rated “good” or “very good” in their deck, superstructure, and substructure components. The lone exception is the bridge on George Washington Highway over Miry Brook (Bridge No. 5933), which recorded “fair” ratings across all three major elements.

State engineers classify “fair” structures as showing noticeable wear but not yet requiring immediate rehabilitation. Still, the rating signals the potential for increased maintenance in the years ahead, particularly as aging infrastructure continues to strain local and state budgets.

The rest of Ridgefield’s crossings show signs of structural strength. Both bridges along Route 35 — one over Mill River and another over a small brook — were rated “very good” in deck condition and “good” in the supporting structure. Two U.S. Route 7 bridges over the Norwalk River also earned "good" marks.

What the National Bridge Inventory Is and How It Classifies Bridges

The National Bridge Inventory is a nationwide database maintained by the Federal Highway Administration that contains detailed structural and condition information on the country’s publicly owned bridges. Every state transportation agency, including the Connecticut Department of Transportation, is required to inspect and report condition ratings for bridges that meet federal criteria.

Which Bridges Are Included in the NBI

A bridge must be included in the NBI if it meets all of the following conditions:

• Has a span of at least 20 feet
• Is publicly owned or located on a public road
• Is inspected at least every 24 months (some more frequently depending on condition)

This includes bridges on interstates, state highways, local roads, and municipal structures.

How the NBI Classifies and Rates Bridges

NBI inspections evaluate several major components of a bridge’s structure. Key elements are assigned numerical condition ratings on a 0–9 scale, where:

• 9 — Excellent
• 8 — Very good
• 7 — Good
• 6 — Fair
• 5 — Poor
• 4 — Serious
• 3 — Critical
• 2 — Imminent failure
• 1 — Failed
• 0 — Gone (no structure remains)

The most important individual ratings are:

• Deck Condition: The physical surface of the bridge that carries traffic — pavement, deck slab, and protective systems.
• Superstructure Condition: The main load-carrying components above the deck, including girders, beams, trusses, and arches.
• Substructure Condition: The supports below the superstructure — abutments, piers, footings, and foundations.
• Culvert Condition: Used for structures that function as culverts rather than traditional bridges.

Overall Classification: “Good,” “Fair,” or “Poor”

FHWA uses these component ratings to classify each bridge:

Good: All major components rated 7 or higher

Fair: One or more components rated 6

Poor: One or more components rated 5 or lower

A bridge classified as “poor” is commonly referred to as structurally deficient, meaning it requires repair or rehabilitation but is not necessarily unsafe.

NBI Ratings are important as they help determine repair priorities for state and federal funding, influence traffic restrictions (e.g., weight limits), and help towns and states assess long-term capital needs.

Bridge-by-Bridge Snapshot for Ridgefield

Bridge 5683 — U.S. Route 7 over Norwalk River

• Deck: Not applicable
• Superstructure: Good (7)
• Substructure: Good (7)
• Overall: Strong structural condition with no major deficiencies noted.

Bridge 2276 — Route 35 over Mill River

• Deck: Very Good (8)
• Superstructure: Good (7)
• Substructure: Good (7)
• Overall: One of Ridgefield’s strongest-rated bridges.

Bridge 2275 — Route 35 over Brook

• Deck: Very Good (8)
• Superstructure: Good (7)
• Substructure: Good (7)
• Overall: Also rated among the town’s highest-quality structures.

Bridge 5933 — George Washington Highway over Miry Brook

• Deck: Fair (6)
• Superstructure: Fair (6)
• Substructure: Fair (6)
• Overall: The only Ridgefield bridge receiving mid-level marks, indicating aging components needing ongoing monitoring.

Bridge 536 — U.S. Route 7 over Norwalk River

• Deck: Very Good (8)
• Superstructure: Good (7)
• Substructure: Good (7)
• Overall: Another sturdy structure along a high-traffic corridor.

How Ridgefield Compares to Statewide Trends

CTDOT oversees more than 5,400 roadway bridges statewide, with the average structure now more than 50 years old. About 5 percent are classified as structurally deficient, though Ridgefield has none in that category based on the most recent inspection cycle.

Still, infrastructure experts warn that even “good” bridges can require increased investment as weather extremes, heavier traffic, and aging components accelerate wear.