US Bridges

N&S405-W105 Conn over Imperial on & Off-Ramps

Good

Los Angeles County, California · 07-LA-405-R21.18-LA · Structure no. 53 2442H

Built
1989
36 years old
Condition
Good
inspected November 2024
Type
Box Beam or Girders - Multiple
Prestressed Concrete Continuous
Length
1,605 ft
11 main spans
Daily traffic
15,001
2019 count
Owner
State
State Highway Agency

About this bridge

N&S405-W105 Conn over Imperial on & Off-Ramps is a prestressed concrete continuous box beam or girders - multiple carrying N&S405-W105 Conn over Imperial on & Off-Ramps in Los Angeles County, California. It was built in 1989, so it is 36 years old, younger than the California average of 54.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 15,001 vehicles a day, roughly 2% of them trucks, projected to reach 16,948 by 2041. The structure is 1,605 ft (489.2 m) long and 41 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesN&S405-W105 Conn
CrossesImperial on & Off-Ramps
Location07-LA-405-R21.18-LA
RouteInterstate 405
CountyLos Angeles County
StateCalifornia
Coordinates33.93052, -118.3767
Functional classUrban Principal Arterial - Interstate

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Last inspectionNovember 2024
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation8: Equal to present desirable criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans11
Design loadHS 20 + Mod
Structure length1,605 ft (489.2 m)
Longest span160 ft (48.8 m)
Deck width41 ft (12.5 m)
Roadway width37 ft (11.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic15,001 (2019)
Projected traffic16,948 by 2041
Trucks2%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkNon-Interstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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 N&S405-W105 Conn over Imperial on & Off-Ramps built?

It was built in 1989, making it 36 years old in 2025.

What condition is N&S405-W105 Conn over Imperial on & Off-Ramps in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in November 2024.

How much traffic does N&S405-W105 Conn over Imperial on & Off-Ramps carry?

About 15,001 vehicles per day (2019 count), of which roughly 2% are trucks.

How long is N&S405-W105 Conn over Imperial on & Off-Ramps?

The structure is 1,605 ft (489.2 m) long with a longest span of 160 ft (48.8 m) and a deck 41 ft wide.

Who owns N&S405-W105 Conn over Imperial on & Off-Ramps?

It is owned by the State Highway Agency.