NDT of Bridges and Structural Steel: Plan Around the Detail

Start with drawings and service history

Identify the member, connection and weld detail on a drawing or location schedule. Review known repairs, previous findings and relevant loading history with the responsible engineer. An inspection location described only as “near the bearing” may be impossible to reproduce on the next visit.

Plan access, traffic management and safe working arrangements with the owner. Limited access should become a recorded coverage limitation, not an unqualified satisfactory result.

Choose the technique for the detail

Visual examination establishes surface condition and context. Appropriate surface methods can investigate accessible crack concerns; ultrasonic techniques may address internal conditions where material, geometry and access allow. FHWA provides technical resources for bridge NDE, including ultrasonic applications.

Coatings, weld shape, attachments and backing can affect interpretation. Demonstrate the proposed technique on representative geometry and agree the examination coverage before it is accepted as a substitute for another method.

Support a repeatable engineering review

Record orientation, length and location of reportable indications, with photographs and measurement references. Preserve the distinction between a finding, its interpretation and the owner’s structural decision. An NDT report does not independently establish bridge load capacity. Track follow-up examinations and repairs against the original detail identifier.

References and next steps

FHWA’s ultrasonic bridge inspection resource provides further background. Use the governing specification and approved procedure for the actual job.

Discuss the examination scope. Include the component, material, service history and decision the inspection needs to support.