US Bridges

IH 45 Nbml over Magnolia Bayou

Good

Galveston County, Texas · 0.30 MI SE of FM 646 · Structure no. 120850050004455

Built
2020
5 years old
Condition
Good
inspected August 2024
Type
Slab
Prestressed Concrete
Length
112 ft
1 main span
Daily traffic
115,900
2016 count
Owner
State
State Highway Agency

About this bridge

IH 45 Nbml over Magnolia Bayou is a prestressed concrete slab carrying IH 45 Nbml over Magnolia Bayou in Galveston County, Texas. It was built in 2020, so it is 5 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 115,900 vehicles a day, roughly 4% of them trucks, projected to reach 159,700 by 2036. The structure is 112 ft (34.1 m) long and 87 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesIH 45 Nbml
CrossesMagnolia Bayou
Location0.30 MI SE of FM 646
RouteInterstate 45
CountyGalveston County
StateTexas
Coordinates29.4625, -95.08775
Functional classUrban Principal Arterial - Interstate

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.
Substructure8 Very GoodNo problems noted.
Channel and channel protection7 GoodSome minor problems.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy9: Superior to present desirable 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 (+2 approach)
Design loadHL 93
Structure length112 ft (34.1 m)
Longest span50 ft (15.2 m)
Deck width87 ft (26.6 m)
Roadway width84 ft (25.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic115,900 (2016)
Projected traffic159,700 by 2036
Trucks4%
Lanes on structure5
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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 IH 45 Nbml over Magnolia Bayou built?

It was built in 2020, making it 5 years old in 2025.

What condition is IH 45 Nbml over Magnolia Bayou 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 2024.

How much traffic does IH 45 Nbml over Magnolia Bayou carry?

About 115,900 vehicles per day (2016 count), of which roughly 4% are trucks.

How long is IH 45 Nbml over Magnolia Bayou?

The structure is 112 ft (34.1 m) long with a longest span of 50 ft (15.2 m) and a deck 87 ft wide.

Who owns IH 45 Nbml over Magnolia Bayou?

It is owned by the State Highway Agency.