US Bridges

Black Rock RD over Mill Creek

Fair

Montgomery County, Pennsylvania · 0.9 MI W SR23 Adc 3478-C5 · Structure no. 000000000027955

Built
1908
117 years old, rebuilt 1999
Condition
Fair
inspected July 2024
Type
Slab
Concrete
Length
30 ft
1 main span
Daily traffic
2,740
2019 count
Owner
County
County Highway Agency

About this bridge

Black Rock RD over Mill Creek is a concrete slab carrying Black Rock RD over Mill Creek in Montgomery County, Pennsylvania. It was built in 1908 and reconstructed in 1999, so it is 117 years old, older than the Pennsylvania average of 54.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 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 2,740 vehicles a day, roughly 12% of them trucks, projected to reach 2,050 by 2018. The structure is 30 ft (9.1 m) long and 26 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesBlack Rock RD
CrossesMill Creek
Location0.9 MI W SR23 Adc 3478-C5
RouteCity Street 0
CountyMontgomery County
StatePennsylvania
Coordinates40.0331, -75.2936
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourCountermeasures installed to correct a previously existing problem
Structural evaluation6: Equal to present minimum criteria
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating72 US tons
Inventory rating43 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length30 ft (9.1 m)
Longest span27 ft (8.2 m)
Deck width26 ft (7.8 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,740 (2019)
Projected traffic2,050 by 2018
Trucks12%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$99,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Black Rock RD over Mill Creek built?

It was built in 1908, making it 117 years old in 2025. It was reconstructed in 1999.

What condition is Black Rock RD over Mill Creek 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 July 2024.

How much traffic does Black Rock RD over Mill Creek carry?

About 2,740 vehicles per day (2019 count), of which roughly 12% are trucks.

How long is Black Rock RD over Mill Creek?

The structure is 30 ft (9.1 m) long with a longest span of 27 ft (8.2 m) and a deck 26 ft wide.

Who owns Black Rock RD over Mill Creek?

It is owned by the County Highway Agency.