US Bridges

Tower Road over Rock Creek

Good

Cowlitz County, Washington · 4.5 MI E of SR 504 MP 2.0 · Structure no. 089367000000000

Built
2022
3 years old
Condition
Good
inspected May 2023
Type
Truss - Thru
Steel
Length
141 ft
1 main span
Daily traffic
325
2021 count
Owner
County
County Highway Agency

About this bridge

Tower Road over Rock Creek is a steel truss - thru carrying Tower Road over Rock Creek in Cowlitz County, Washington. It was built in 2022, so it is 3 years old, younger than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. Its operating status is: open, temporary structure in place while original is closed.

It carries about 325 vehicles a day, roughly 30% of them trucks, projected to reach 600 by 2041. The structure is 141 ft (43 m) long and 24 ft wide. If it were closed, the detour would be 19.9 mi (32 km).

Location

Open in Google Maps
CarriesTower Road
CrossesRock Creek
Location4.5 MI E of SR 504 MP 2.0
RouteCounty Highway 51200
CountyCowlitz County
StateWashington
Coordinates46.34722, -122.81695
Functional classRural Major Collector

Condition and inspection

Good

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

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, temporary structure in place while original is closed
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating0 US tons
Inventory rating0 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckSteel plate
Main spans1
Design loadHL 93
Structure length141 ft (43 m)
Longest span140 ft (42.6 m)
Deck width24 ft (7.3 m)
Roadway width18 ft (5.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic325 (2021)
Projected traffic600 by 2041
Trucks30%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed19.9 mi (32 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$3.7 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Tower Road over Rock Creek built?

It was built in 2022, making it 3 years old in 2025.

What condition is Tower Road over Rock Creek 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 May 2023.

How much traffic does Tower Road over Rock Creek carry?

About 325 vehicles per day (2021 count), of which roughly 30% are trucks.

How long is Tower Road over Rock Creek?

The structure is 141 ft (43 m) long with a longest span of 140 ft (42.6 m) and a deck 24 ft wide.

Who owns Tower Road over Rock Creek?

It is owned by the County Highway Agency.