US Bridges

County Road 35 over St. Vrain Creek

Fair

Boulder County, Colorado · 0.2 Miles South of County · Structure no. BC-35-0.2-SV1

Built
1996
29 years old
Condition
Fair
inspected January 2025
Type
Stringer/Multi-beam or Girder
Steel
Length
94 ft
2 main spans
Daily traffic
78
2023 count
Owner
County
County Highway Agency

About this bridge

County Road 35 over St. Vrain Creek is a steel stringer/multi-beam or girder carrying County Road 35 over St. Vrain Creek in Boulder County, Colorado. It was built in 1996, so it is 29 years old, younger than the Colorado average of 42.2 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 78 vehicles a day, roughly 6% of them trucks, projected to reach 93 by 2043. The structure is 94 ft (28.8 m) long and 31 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesCounty Road 35
CrossesSt. Vrain Creek
Location0.2 Miles South of County
RouteCounty Highway 0
CountyBoulder County
StateColorado
Coordinates40.1866, -105.19107
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure8 Very GoodNo problems noted.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJanuary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating60.3 US tons
Inventory rating36.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans2
Design loadUnknown
Structure length94 ft (28.8 m)
Longest span44 ft (13.5 m)
Deck width31 ft (9.4 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic78 (2023)
Projected traffic93 by 2043
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was County Road 35 over St. Vrain Creek built?

It was built in 1996, making it 29 years old in 2025.

What condition is County Road 35 over St. Vrain Creek in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in January 2025.

How much traffic does County Road 35 over St. Vrain Creek carry?

About 78 vehicles per day (2023 count), of which roughly 6% are trucks.

How long is County Road 35 over St. Vrain Creek?

The structure is 94 ft (28.8 m) long with a longest span of 44 ft (13.5 m) and a deck 31 ft wide.

Who owns County Road 35 over St. Vrain Creek?

It is owned by the County Highway Agency.