US Bridges

N. 61st Street over Boulder Creek

Fair

Boulder County, Colorado · 1.0 MI So of Jay Road · Structure no. BC-39-9.9-BO-1

Built
1986
39 years old
Condition
Fair
inspected January 2025
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
94 ft
2 main spans
Daily traffic
5,789
2023 count
Owner
County
County Highway Agency

About this bridge

N. 61st Street over Boulder Creek is a prestressed concrete box beam or girders - multiple carrying N. 61st Street over Boulder Creek in Boulder County, Colorado. It was built in 1986, so it is 39 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 5,789 vehicles a day, roughly 12% of them trucks, projected to reach 6,947 by 2043. The structure is 94 ft (28.5 m) long and 31 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

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CarriesN. 61st Street
CrossesBoulder Creek
Location1.0 MI So of Jay Road
RouteCounty Highway 0
CountyBoulder County
StateColorado
Coordinates40.03805, -105.21141
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
Deck9 ExcellentNo problems noted.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
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 evaluation6: Equal to present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating52 US tons
Inventory rating31.1 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckOther
Main spans2
Design loadHS 20
Structure length94 ft (28.5 m)
Longest span44 ft (13.4 m)
Deck width31 ft (9.5 m)
Roadway width30 ft (9.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,789 (2023)
Projected traffic6,947 by 2043
Trucks12%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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 proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost$478,000 (2019 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was N. 61st Street over Boulder Creek built?

It was built in 1986, making it 39 years old in 2025.

What condition is N. 61st Street over Boulder 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 N. 61st Street over Boulder Creek carry?

About 5,789 vehicles per day (2023 count), of which roughly 12% are trucks.

How long is N. 61st Street over Boulder Creek?

The structure is 94 ft (28.5 m) long with a longest span of 44 ft (13.4 m) and a deck 31 ft wide.

Who owns N. 61st Street over Boulder Creek?

It is owned by the County Highway Agency.