Wet fireproofing causes building column corrosion

• Published in: Materials performance Vol. 36; no. 5; pp. 70 - 71
• Main Authors: THOMPSON, T. S, MCDONALD, D. B
• Format: Magazine Article
• Language: English
• Published: Houston, TX National Association of Corrosion Engineers 01.05.1997; NACE International
• Subjects: Applied sciences; Buildings. Public works; Corrosion; Durability. Pathology. Repairing. Maintenance; Exact sciences and technology; Corrosion; Column; Failure analysis; Old building; Inspection; Fireproofing agent; Steel
• ISSN: 0094-1492

An inspection of a 20-year-old building structure was performed to determine the sources of water ingress onto the floor slab at a second basement level. The building is a multistory, steel-framed beam-and-column structure. One of the steel building columns (specified to be ASTM A 36 super(1)) is supported at a second level basement located approximately 14 ft (4.2 m) below the adjacent exterior grade elevation. The column extends to 1 ft (0.3 m) below the "slab on grade" at this level of the building, and is supported on a cast-in-place concrete caisson. The inspection of the building interior at this location revealed that some of the original spray-on fireproofing on the existing steel column was in contact with the concrete floor slab and was wet for a length of similar to 6 ft (1.8 m) above the floor level. Removal of some of the fireproofing material near the base of the column showed that the steel column was corroded underneath. A more detailed inspection of the existing steel column was then performed.