What It Means
Bridge inspection is the systematic, hands-on examination of a bridge's structural, functional, and operational characteristics to document its condition and identify maintenance needs. Federal law under the National Bridge Inspection Standards (NBIS, 23 CFR 650 Subpart C) requires every bridge longer than 20 feet on a public road to be inspected at least every 24 months by a certified Team Leader. The NBIS was originally promulgated in 1971 in response to the 1967 Silver Bridge collapse on the Ohio River that killed 46 people, and was substantially updated in May 2022 to incorporate element-level inspection, risk-based intervals, enhanced qualifications, and formal recognition of System Redundant Members. The 2022 update introduced risk-based inspection intervals: bridges in Good condition on stable foundations may qualify for extended 48-month intervals, while bridges in Poor condition or with critical findings may require 12-month or shorter cycles. Inspection types include Initial (first inspection after construction), Routine (standard biennial visual inspection), In-Depth (close-up examination of specific elements), Damage (following impact, flood, earthquake, or fire), Special (for unique concerns like fatigue monitoring or settlement tracking), and Underwater (for substructure elements below waterline, required every 60 months or shorter). Specialized nondestructive evaluation methods include ground-penetrating radar for deck delamination, ultrasonic testing for fatigue cracks and weld defects, impact-echo for concrete integrity, half-cell potential for active rebar corrosion, and increasingly drone-based visual inspection for hard-to-reach elements on tall piers and long spans. Inspectors must be qualified under NBIS: Team Leaders require specific combinations of professional engineering licensure, bridge inspection experience, and completion of FHWA-NHI course 130055 (Safety Inspection of In-Service Bridges), typically an 80-hour classroom and field program with periodic refresher training. Inspection results are recorded on state-specific inspection report forms and summarized in the NBI condition ratings. States submit annual NBI updates to FHWA, typically by April 1 for the prior calendar year, and the aggregate dataset drives federal bridge condition statistics and the BridgeWatch Condition Score.
Bridge Inspection is one of the bridge-engineering or FHWA-policy concepts that recurs across BridgeSafety. Below is how the concept connects to the National Bridge Inventory data behind every page on the site.
Within the BridgeSafety Condition Score, each primary component (deck, superstructure, substructure) contributes about a third of the rating, with an age penalty applied to bridges past their typical design life. The methodology page describes the scoring in full detail.
Frequently Asked Questions
What does "Bridge Inspection" mean?
A systematic examination of a bridge's structural components required by federal law, typically every 24 months under the NBIS.
Why does Bridge Inspection matter for bridge safety?
Bridge inspection is the systematic, hands-on examination of a bridge's structural, functional, and operational characteristics to document its condition and identify maintenance needs. Federal law under the National Bridge Inspection Standards (NBIS, 23 CFR 650 Subpart C) requires every bridge long...