US Bridges

NW700 over Knob CR

Poor

Henry County, Missouri · S 32 T 42 N R 28 W · Structure no. 13073

Built
1950
75 years old
Condition
Poor
inspected March 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
72 ft
3 main spans
Daily traffic
50
2023 count
Owner
County
County Highway Agency

About this bridge

NW700 over Knob CR is a steel continuous stringer/multi-beam or girder carrying NW700 over Knob CR in Henry County, Missouri. It was built in 1950, so it is 75 years old, older than the Missouri average of 45.1 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 50 vehicles a day, roughly 10% of them trucks, projected to reach 70 by 2043. The structure is 72 ft (21.9 m) long and 20 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesNW700
CrossesKnob CR
LocationS 32 T 42 N R 28 W
RouteCounty Highway 28
CountyHenry County
StateMissouri
Coordinates38.46533, -94.03949
Functional classRural Local

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Channel and channel protection4 PoorAdvanced section loss, deterioration, spalling or scour.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating45.6 US tons
Inventory rating25.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 15
Structure length72 ft (21.9 m)
Longest span26 ft (7.9 m)
Deck width20 ft (6.1 m)
Roadway width18 ft (5.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic50 (2023)
Projected traffic70 by 2043
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$370,000 (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was NW700 over Knob CR built?

It was built in 1950, making it 75 years old in 2025.

What condition is NW700 over Knob CR in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in March 2023.

How much traffic does NW700 over Knob CR carry?

About 50 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is NW700 over Knob CR?

The structure is 72 ft (21.9 m) long with a longest span of 26 ft (7.9 m) and a deck 20 ft wide.

Who owns NW700 over Knob CR?

It is owned by the County Highway Agency.