Q.: Where can we find information on systems for reinforcing building slabs built in the 1930s, and earlier?

A.: One reference is the Concrete Reinforcing Steel Institute (CRSI) publication, "Evaluation of Reinforcing Steel Systems in Old Reinforced Concrete Structures." The 16-page publication can be ordered from CRSI, 933 N. Plum Grove Rd., Schaumburg IL 60173 (708-517-1200; fax 708.517.1200).

In evaluating these old systems, you may find that the bar layout and mechanical properties tensile strength and bond are significantly different than those used in present practice.