MARY HARRISON MINE
Carrying MARY HARRISON MINE over MAXWELL CREEK
AT SH 132, Mariposa, California
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
MARY HARRISON MINE in Mariposa, California sits above 9% of rated California bridges on inventory load rating (19 t), while its 1926 build year is earlier than 86% of Mariposa's recorded-year cohort (109 bridges).
MARY HARRISON MINE in Mariposa, California is rated Poor in the FHWA's 2024 National Bridge Inventory. Built in 1926, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 4. The lowest applicable rating sets the federal condition category, so this Poor result describes the weakest reported component rather than the structure as a whole. No NBI category is a closure decision or a live crossing-safety verdict.
NBI record plate
Structure CA:40C0031
PRE-1950 · STEEL · SINGLE-SPAN · DECK-LED · TRACE-ADT · LIGHT-LOAD · CAT-POOR
- PRE-1950 Pre-1950
- STEEL Steel
- SINGLE-SPAN Single span
- DECK-LED Deck-led
- TRACE-ADT Trace ADT
- LIGHT-LOAD Light load
- CAT-POOR Poor
Inspection-sheet codes from this record’s year, material family, spans, controlling component, ADT, inventory load, and NBI category, not a live closure verdict.
Bridge Snapshot: MARY HARRISON MINE
The MARY HARRISON MINE bridge in Mariposa, California carries MARY HARRISON MINE over MAXWELL CREEK. It was built in 1926, making it 100 years old today. It was last reconstructed in 1942, extending its service life. The structure is built primarily of steel and spans 1 section, stretching 10.1 meters (33 feet) end to end. Daily traffic averages 10 vehicles, placing it in the lower-traffic tier of California bridges. It is owned and maintained by County Highway Agency.
The latest FHWA inspection records show a deck rating of 4/9, superstructure at 5/9, substructure at 7/9. The weakest component sits in poor condition. A component scored 4 or below, placing this bridge in the federal Poor condition category rather than declaring it unsafe or closed.
How MARY HARRISON MINE compares
Age against the county: built in 1926, earlier than 94 of Mariposa's 109 bridges with a recorded construction year (86%), against a county median build year of 1956. Age is not a defect on its own, but it is the population from which future Poor ratings are drawn.
Live comparison across California bridges with a recorded inventory load rating (25,538 of 25,848 rated).
MARY HARRISON MINE vs every rated California bridge
Inventory load rating (metric tons), FHWA NBI, this state
19 Top 91% higher than 9% of 25,538 bridges
rated California bridges, bucketed by value
Each bar is a band; taller bars hold more bridges. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source FHWA National Bridge Inventory · August 2026
Condition Ratings
Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.
Reported 0–9 component ratings from the FHWA NBI. The highlighted component is the lowest reported input to this record’s current condition category; it is not a closure or live crossing-safety decision.
Mariposa inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 109 bridges in this county. Orthogonal to this structure's component profile above: a county catalog share, not a live crossing-safety verdict.
Structural Details
- Year Built
- 1926
- Last Reconstructed
- 1942
- Material
- Steel
- Number of Spans
- 1
- Structure Length
- 10.1 m (33 ft)
- Deck Width
- 6.0 m (20 ft)
- Owner
- County Highway Agency
- Avg Daily Traffic
- 10 vehicles/day
- Structure Number
- 40C0031
Condition Analysis
- • At 4/9, the deck (driving surface) is in poor shape, with advanced wear on file for this vintage.
- • At 5/9, the superstructure (beams and supports above the deck) shows fair condition, with minor wear flagged for upkeep.
- • The substructure (piers and abutments) is in good condition (7/9), showing no significant deterioration.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
MARY HARRISON MINE 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 MARY HARRISON MINE against other structures in Mariposa and across California. California 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 MARY HARRISON MINE?
MARY HARRISON MINE in Mariposa, California has a deck rating of 4/9, superstructure rating of 5/9, and substructure rating of 7/9 on the FHWA's 0–9 scale.
How often is MARY HARRISON MINE inspected?
MARY HARRISON MINE'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 10 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. MARY HARRISON MINE 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 MARY HARRISON MINE?
MARY HARRISON MINE has an NBI inventory load rating of 18.8 metric tons.
Who is responsible for maintaining MARY HARRISON MINE?
MARY HARRISON MINE is owned and maintained by County Highway Agency.
How old is MARY HARRISON MINE and does age affect safety?
MARY HARRISON MINE was built in 1926, making it 100 years old and last reconstructed in 1942.
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.
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Send this source-bounded record or download its data card. An NBI condition category is not a closure or live crossing-safety verdict.
Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. Component ratings, ADT, and condition category on this page are copied from the NBI record for this structure; no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2024 NBI release. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.