CORROSION OF INACCESSIBLE CLOSED-SECTION MEMBERS: CURRENT CONDITIONS AND PROPOSED COUNTERMEASURES

Abstract

 Small closed-section members with inaccessible interiors (“inaccessible members”) are commonly used in steel road and pedestrian bridges, yet their internal corrosion conditions remain insufficiently identified, even under regular inspections introduced in 2014. Surveys of pedestrian bridges revealed corrosion in all examined members, with thickness losses up to 2.5 mm. Short-term monitoring with ACM sensors further showed corrosion rates far exceeding those reported in box girders under chloride environments. This study proposes countermeasures including enhanced inspections, methods to assess corrosion rates for timely interventions, and design considerations for new members.