Mission ST over South 21st Street
PoorPosted for loadAllegheny County, Pennsylvania · 061 Mission ST West · Structure no. 000000000002428
- Built
- 1939
- 86 years old, rebuilt 1982
- Condition
- Poor
- inspected September 2024
- Type
- Girder and Floorbeam System
- Steel Continuous
- Length
- 394 ft
- 3 main spans
- Daily traffic
- 650
- 2020 count
- Owner
- City
- City or Municipal Highway Agency
About this bridge
Mission ST over South 21st Street is a steel continuous girder and floorbeam system carrying Mission ST over South 21st Street in Allegheny County, Pennsylvania. It was built in 1939 and reconstructed in 1982, so it is 86 years old, older than the Pennsylvania average of 54.8 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. Its operating status is: posted for load restriction.
It carries about 650 vehicles a day, roughly 4% of them trucks, projected to reach 650 by 2040. The structure is 394 ft (120.1 m) long and 36 ft wide. If it were closed, the detour would be 1.9 mi (3 km).
Location
Open in Google MapsCondition and inspection
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.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 6 Satisfactory | Structural elements show some minor deterioration. |
| Superstructure | 4 Poor | Advanced section loss, deterioration, spalling or scour. |
| Substructure | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was Mission ST over South 21st Street built?
It was built in 1939, making it 86 years old in 2025. It was reconstructed in 1982.
What condition is Mission ST over South 21st Street 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 September 2024.
How much traffic does Mission ST over South 21st Street carry?
About 650 vehicles per day (2020 count), of which roughly 4% are trucks.
How long is Mission ST over South 21st Street?
The structure is 394 ft (120.1 m) long with a longest span of 160 ft (48.8 m) and a deck 36 ft wide.
Who owns Mission ST over South 21st Street?
It is owned by the City or Municipal Highway Agency.