US Bridges

Nacimiento Lake DR over Lake Nacimiento Dam Spwy

Fair

San Luis Obispo County, California · 15 MI NW of SR 101 · Structure no. 49C0347

Built
1956
69 years old
Condition
Fair
inspected June 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
163 ft
2 main spans
Daily traffic
1,772
2018 count
Owner
Local
Other Local Agency

About this bridge

Nacimiento Lake DR over Lake Nacimiento Dam Spwy is a steel stringer/multi-beam or girder carrying Nacimiento Lake DR over Lake Nacimiento Dam Spwy in San Luis Obispo County, California. It was built in 1956, so it is 69 years old, older than the California average of 54.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 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 1,772 vehicles a day, roughly 5% of them trucks, projected to reach 2,157 by 2044. The structure is 163 ft (49.7 m) long and 30 ft wide. If it were closed, the detour would be 34.2 mi (55 km).

Location

Open in Google Maps
CarriesNacimiento Lake DR
CrossesLake Nacimiento Dam Spwy
Location15 MI NW of SR 101
RouteCounty Highway 0
CountySan Luis Obispo County
StateCalifornia
Coordinates35.76047, -120.88495
Functional classRural Major Collector

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating28.2 US tons
Inventory rating16.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans2
Design loadH 15
Structure length163 ft (49.7 m)
Longest span80 ft (24.4 m)
Deck width30 ft (9.2 m)
Roadway width24 ft (7.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,772 (2018)
Projected traffic2,157 by 2044
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed34.2 mi (55 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerOther Local Agency
Maintained byOther Local Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Nacimiento Lake DR over Lake Nacimiento Dam Spwy built?

It was built in 1956, making it 69 years old in 2025.

What condition is Nacimiento Lake DR over Lake Nacimiento Dam Spwy 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 June 2024.

How much traffic does Nacimiento Lake DR over Lake Nacimiento Dam Spwy carry?

About 1,772 vehicles per day (2018 count), of which roughly 5% are trucks.

How long is Nacimiento Lake DR over Lake Nacimiento Dam Spwy?

The structure is 163 ft (49.7 m) long with a longest span of 80 ft (24.4 m) and a deck 30 ft wide.

Who owns Nacimiento Lake DR over Lake Nacimiento Dam Spwy?

It is owned by the Other Local Agency.