US Bridges

FM 518 over Interurban Ditch

Good

Galveston County, Texas · 0.40 MI W of SH 3 · Structure no. 120850097603038

Built
1995
30 years old
Condition
Good
inspected September 2024
Type
Slab
Prestressed Concrete
Length
50 ft
1 main span
Daily traffic
23,790
2023 count
Owner
State
State Highway Agency

About this bridge

FM 518 over Interurban Ditch is a prestressed concrete slab carrying FM 518 over Interurban Ditch in Galveston County, Texas. It was built in 1995, so it is 30 years old, younger than the Texas average of 44.4 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 23,790 vehicles a day, roughly 5% of them trucks, projected to reach 30,900 by 2033. The structure is 50 ft (15.2 m) long and 78 ft wide. If it were closed, the detour would be 5 mi (8 km).

CarriesFM 518
CrossesInterurban Ditch
Location0.40 MI W of SH 3
RouteState Highway 518
StateTexas
Coordinates29.50623, -95.10144
Functional classUrban Other Principal 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.
Superstructure8 Very GoodNo problems noted.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourCountermeasures installed to correct a previously existing problem
Structural evaluation7: Better than present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating60 US tons
Inventory rating36 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length50 ft (15.2 m)
Longest span50 ft (15.2 m)
Deck width78 ft (23.7 m)
Roadway width64 ft (19.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic23,790 (2023)
Projected traffic30,900 by 2033
Trucks5%
Lanes on structure5
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 km)
TollOn a free road
National Highway SystemYes

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—
NavigationNo navigation control on waterway

Frequently asked questions

When was FM 518 over Interurban Ditch built?

It was built in 1995, making it 30 years old in 2025.

What condition is FM 518 over Interurban Ditch 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 September 2024.

How much traffic does FM 518 over Interurban Ditch carry?

About 23,790 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is FM 518 over Interurban Ditch?

The structure is 50 ft (15.2 m) long with a longest span of 50 ft (15.2 m) and a deck 78 ft wide.

Who owns FM 518 over Interurban Ditch?

It is owned by the State Highway Agency.