US Bridges

Md 121 over Is 270

Good

Montgomery County, Maryland · 0.64 Mile South of Md 355 · Structure no. 100000150038010

Built
1997
28 years old
Condition
Good
inspected August 2023
Type
Girder and Floorbeam System
Steel Continuous
Length
295 ft
2 main spans
Daily traffic
13,714
2009 count
Owner
State
State Highway Agency

About this bridge

Md 121 over Is 270 is a steel continuous girder and floorbeam system carrying Md 121 over Is 270 in Montgomery County, Maryland. It was built in 1997, so it is 28 years old, younger than the Maryland average of 52.6 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 13,714 vehicles a day, projected to reach 16,293 by 2026. The structure is 295 ft (89.9 m) long and 99 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesMd 121
CrossesIs 270
Location0.64 Mile South of Md 355
RouteState Highway 121
CountyMontgomery County
StateMaryland
Coordinates39.23157, -77.28526
Functional classUrban Minor Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating91.9 US tons
Inventory rating55 US tons

Structure

Structure typeGirder and Floorbeam System
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 25 or greater
Structure length295 ft (89.9 m)
Longest span145 ft (44.2 m)
Deck width99 ft (30.1 m)
Roadway width80 ft (24.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,714 (2009)
Projected traffic16,293 by 2026
Trucks—
Lanes on structure6
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was Md 121 over Is 270 built?

It was built in 1997, making it 28 years old in 2025.

What condition is Md 121 over Is 270 in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in August 2023.

How much traffic does Md 121 over Is 270 carry?

About 13,714 vehicles per day (2009 count).

How long is Md 121 over Is 270?

The structure is 295 ft (89.9 m) long with a longest span of 145 ft (44.2 m) and a deck 99 ft wide.

Who owns Md 121 over Is 270?

It is owned by the State Highway Agency.