Historically, it was seen as a smart financial move to make the whole building of the same structural material, wherever possible, to avoid adding another trade to the project. When the building structure happens to be structural steel, that reasoning led to extremely expensive repairs to structural steel buildings with below-grade parking structures. There are two primary problems with a below-grade structural steel parking structure. First, they tend to have moisture infiltration problems. Second, they require fireproofing to protect the steel from fire damage. Fireproofed structural steel is not normally painted because paint can interfere with the bond of the fireproofing. If lightweight fibrous fireproofing is used, it creates a sponge right next to the steel surface. Add water, and you have a million dollar problem.
When designing repairs for corrosion-damaged structures, TSA performs ultrasonic thickness testing of the steel members, then analyzes the structures to determine if they have sufficient residual capacity to still meet the Building Code. If they don't, TSA designs reinforcement. Our reinforcement designs include steel reinforcement and encasement of the steel beams in reinforced concrete. If the analysis shows that the structure still meets Code, the repair typically consists of a high-quality paint that is compatible with fireproofing, and a specialty fireproofing that does not hold water like fibrous waterproofing.
