US Bridges

SR 18 over Salmon Ditch

Fair

Benton County, Indiana · 00.59 W SR 71 · Structure no. 004520

Built
2005
20 years old
Condition
Fair
inspected January 2024
Type
Slab
Concrete Continuous
Length
60 ft
3 main spans
Daily traffic
235
2021 count
Owner
State
State Highway Agency

About this bridge

SR 18 over Salmon Ditch is a concrete continuous slab carrying SR 18 over Salmon Ditch in Benton County, Indiana. It was built in 2005, so it is 20 years old, younger than the Indiana average of 46.6 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 235 vehicles a day, roughly 29% of them trucks, projected to reach 334 by 2032. The structure is 60 ft (18.2 m) long and 35 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesSR 18
CrossesSalmon Ditch
Location00.59 W SR 71
RouteState Highway 18
CountyBenton County
StateIndiana
Coordinates40.62238, -87.50216
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJanuary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating49.3 US tons
Inventory rating37.8 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length60 ft (18.2 m)
Longest span23 ft (7 m)
Deck width35 ft (10.6 m)
Roadway width31 ft (9.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic235 (2021)
Projected traffic334 by 2032
Trucks29%
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

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was SR 18 over Salmon Ditch built?

It was built in 2005, making it 20 years old in 2025.

What condition is SR 18 over Salmon Ditch 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 2024.

How much traffic does SR 18 over Salmon Ditch carry?

About 235 vehicles per day (2021 count), of which roughly 29% are trucks.

How long is SR 18 over Salmon Ditch?

The structure is 60 ft (18.2 m) long with a longest span of 23 ft (7 m) and a deck 35 ft wide.

Who owns SR 18 over Salmon Ditch?

It is owned by the State Highway Agency.