IS 270 E
IS 270 E in S 1312 T 46 N R 5 E, St. Louis County, Missouri received a condition grade of C (50/100). Built in 1965, the bridge carries 137K vehicles daily on IS 270 E over Cst West Port Plaza DR. It is classified as structurally deficient.
IS 270 E carries a C on the BridgeSafety Condition Score with 50/100. Component ratings sit in the middle of the FHWA NBI distribution; rehabilitation programming is likely on the owning agency’s medium-term horizon.
The bridge was built in 1965 and is now 61 years old, at or past the typical 50-year design life for bridges of its vintage. Maintenance and inspection cycles are correspondingly more involved than for newer structures. IS 270 E carries an average daily traffic count of 137,112 vehicles, with 10 lane(s) crossing Cst West Port Plaza DR. The owning agency is State Highway Agency; bridge inspection records flow into the federal NBI database annually.
Component Ratings
The riding surface, evaluated for cracking, spalling, and wear
Beams, girders, and trusses that support the deck
Piers, abutments, and foundations below the deck
Bridge Details
About This Bridge
IS 270 E is a 61-year-old bridge located S 1312 T 46 N R 5 E in St. Louis County, Missouri. The bridge carries IS 270 E over Cst West Port Plaza DR with 10 traffic lanes, handling approximately 137K vehicles per day. Built in 1965 and reconstructed in 1984, the structure spans 46.6 meters.
The bridge received a Condition Grade of C (50/100) based on Federal Highway Administration inspection data. Its deck is rated 5/9 (fair), superstructure 4/9 (poor), and substructure 6/9 (fair). The bridge is classified as structurally deficient, meaning at least one major component is rated 4 or below, this signals a need for repair or replacement but does not necessarily indicate an immediate safety hazard.
This bridge is owned and maintained by State Highway Agency.
Location Map
Frequently Asked Questions
IS 270 E has a Condition Score of 50/100 (Grade C). Its deck is rated 5/9, superstructure 4/9, and substructure 6/9 on the NBI scale. The bridge is classified as structurally deficient.
IS 270 E was built in 1965 and reconstructed in 1984, making it 61 years old. The average bridge age in the United States is 48 years.
IS 270 E carries approximately 137K vehicles per day (average daily traffic). The bridge has 10 traffic lanes. It is 46.6 meters long and located on IS 270 E in S 1312 T 46 N R 5 E, St. Louis County, Missouri.
Yes, IS 270 E is classified as structurally deficient because at least one of its primary components (deck, superstructure, or substructure) is rated 4 or below on the 0-9 NBI scale. This does not necessarily mean it is unsafe, but it requires significant repair or replacement.
IS 270 E is located S 1312 T 46 N R 5 E in St. Louis County, Missouri. The bridge carries IS 270 E over Cst West Port Plaza DR. Its coordinates are 38.703922, -90.449883. It is maintained by State Highway Agency.
IS 270 E carries IS 270 E over Cst West Port Plaza DR. The bridge is 46.6 meters long and was built in 1965, with reconstruction in 1984.
Condition Score is calculated from deck (33%), superstructure (33%), and substructure (34%) NBI ratings with an age penalty for bridges over 50 years.
Source: FHWA National Bridge Inventory, 2026.