US Bridges

Spencer HWY over Big Island Slough

Fair

Harris County, Texas · 0.5 MI E of Underwood RD · Structure no. 121020AA0593004

Built
1992
33 years old
Condition
Fair
inspected September 2023
Type
Slab
Prestressed Concrete
Length
102 ft
3 main spans
Daily traffic
45,486
2013 count
Owner
County
County Highway Agency

About this bridge

Spencer HWY over Big Island Slough is a prestressed concrete slab carrying Spencer HWY over Big Island Slough in Harris County, Texas. It was built in 1992, so it is 33 years old, younger than the Texas average of 44.4 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 45,486 vehicles a day, projected to reach 20,000 by 2030. The structure is 102 ft (31.1 m) long and 96 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesSpencer HWY
CrossesBig Island Slough
Location0.5 MI E of Underwood RD
RouteCounty Highway 20
CountyHarris County
StateTexas
Coordinates29.66446, -95.0784
Functional classUrban Other Principal Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2023
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 adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating36 US tons
Inventory rating27 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadUnknown
Structure length102 ft (31.1 m)
Longest span33 ft (10.1 m)
Deck width96 ft (29.3 m)
Roadway width82 ft (25 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic45,486 (2013)
Projected traffic20,000 by 2030
Trucks0%
Lanes on structure7
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedOther structural work, including hydraulic replacements
Estimated improvement cost$209,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Spencer HWY over Big Island Slough built?

It was built in 1992, making it 33 years old in 2025.

What condition is Spencer HWY over Big Island Slough 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 September 2023.

How much traffic does Spencer HWY over Big Island Slough carry?

About 45,486 vehicles per day (2013 count).

How long is Spencer HWY over Big Island Slough?

The structure is 102 ft (31.1 m) long with a longest span of 33 ft (10.1 m) and a deck 96 ft wide.

Who owns Spencer HWY over Big Island Slough?

It is owned by the County Highway Agency.