US Bridges

100th ST over Drainage

Fair

Montgomery County, Iowa · 073360605 · Structure no. 000000000256011

Built
1990
35 years old
Condition
Fair
inspected June 2024
Type
Slab
Concrete Continuous
Length
103 ft
3 main spans
Daily traffic
20
2022 count
Owner
County
County Highway Agency

About this bridge

100th ST over Drainage is a concrete continuous slab carrying 100th ST over Drainage in Montgomery County, Iowa. It was built in 1990, so it is 35 years old, younger than the Iowa average of 45.5 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 20 vehicles a day, projected to reach 20 by 2044. The structure is 103 ft (31.4 m) long and 27 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
Carries100th ST
CrossesDrainage
Location073360605
RouteCounty Highway 0
CountyMontgomery County
StateIowa
Coordinates41.15852, -95.03004
Functional classRural Local

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating70 US tons
Inventory rating41 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length103 ft (31.4 m)
Longest span39 ft (11.9 m)
Deck width27 ft (8.3 m)
Roadway width27 ft (8.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic20 (2022)
Projected traffic20 by 2044
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 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 proposedOther structural work, including hydraulic replacements
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was 100th ST over Drainage built?

It was built in 1990, making it 35 years old in 2025.

What condition is 100th ST over Drainage 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 100th ST over Drainage carry?

About 20 vehicles per day (2022 count).

How long is 100th ST over Drainage?

The structure is 103 ft (31.4 m) long with a longest span of 39 ft (11.9 m) and a deck 27 ft wide.

Who owns 100th ST over Drainage?

It is owned by the County Highway Agency.