315TH ST
Carrying 315TH ST over MOSQUITO CREEK
078412003, Harrison, Iowa
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: 315TH ST
The 315TH ST bridge in Harrison, Iowa carries 315TH ST over MOSQUITO CREEK. It was built in 1930, making it 96 years old today. It was last reconstructed in 1993, extending its service life. The structure is built primarily of steel and spans 2 sections, stretching 67.7 meters (222 feet) end to end. Daily traffic averages 20 vehicles, placing it in the lower-traffic tier of Iowa bridges. It is owned and maintained by County Highway Agency.
The latest FHWA inspection records show a deck rating of 5/9, superstructure at 5/9, substructure at 4/9. The weakest component sits in poor condition. Because at least one major component scores 4 or lower, this bridge falls in FHWA's Poor condition category. That category is not a closure order. Its NBI inventory load rating is 9.1 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How 315TH ST compares
Live comparison across Iowa.
Historical Sufficiency Rating
PlainBridge-computedFHWA discontinued this calculated item; it does not determine current condition, funding eligibility, posting, or closure. How the historical reference is calculated.
Condition Ratings
Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.
Structural Details
- Year Built
- 1930
- Last Reconstructed
- 1993
- Material
- Steel
- Number of Spans
- 2
- Structure Length
- 67.7 m (222 ft)
- Deck Width
- 5.1 m (17 ft)
- Owner
- County Highway Agency
- Avg Daily Traffic
- 20 vehicles/day
- Structure Number
- 000000000177050
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • The deck (driving surface) is in fair condition (5/9), with minor deterioration that may require routine maintenance.
- • The superstructure (beams and supports above the deck) rates fair at 5/9, minor deterioration that routine maintenance should address.
- • At 4/9, the substructure (piers and abutments) is in poor shape, with advanced wear flagged for priority repair.
How to read this record
315TH ST is in the federal Poor condition category. That is a component-based result, not a closure order.
- NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
- Understand what Poor condition does and does not mean before drawing conclusions. Poor condition explained
- Compare 315TH ST against other structures in Harrison and across Iowa. Iowa bridges
- Noticed visible damage or a safety concern? Report it to the agency that owns the bridge, or call 911 in an emergency. How to report a bridge
Condition codes come straight from the FHWA National Bridge Inventory and are not a real-time safety judgment. Only the owning agency, a state DOT, county, or other owner, can post, restrict, or close a bridge.
Frequently Asked Questions
What do the condition ratings mean for 315TH ST?
315TH ST in Harrison, Iowa has a deck rating of 5/9, superstructure rating of 5/9, and substructure rating of 4/9 on the FHWA's 0–9 scale.
How often is 315TH ST inspected?
315TH ST's responsible agency sets its routine interval under FHWA's risk-based inspection rules; this page does not expose the scheduled interval. It carries about 20 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. 315TH ST is currently shown as Poor condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for 315TH ST?
315TH ST has an NBI inventory load rating of 9.1 metric tons.
Who is responsible for maintaining 315TH ST?
315TH ST is owned and maintained by County Highway Agency.
How old is 315TH ST and does age affect safety?
315TH ST was built in 1930, making it 96 years old and last reconstructed in 1993.
Disclaimer: Bridge condition data is from the FHWA NBI and reflects the last reported inspection. A Poor condition rating is not a live declaration that a bridge is closed or unsafe for travel. For current closure, posting, or safety information, contact the responsible transportation agency.
Every figure on PlainBridge is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.