A. Monolithic concrete walls having less than two-tenths of one percent (0.2%) of reinforcing steel shall be considered as plain concrete walls and the thickness of single bearing walls of plain concrete shall be in accordance with the recommendations in the report of the American Standard Building Code Requirements for Masonry, 1944 Edition, published by the National Bureau of Standards of the United States Department of Commerce.
B. Subject to the other requirements of this Chapter, reinforced concrete bearing walls shall have a thickness of not less than six inches (6") for the top story with a thickness of succeeding lower stories including basement, increasing at the rate of one inch (1") for each two (2) stories.
C. In such walls the amount of reinforcement shall be at least two-tenths of one percent (0.2%) in each direction, horizontal and vertical, the steel being equally distributed on each face of the wall within a maximum bar spacing of twenty four inches (24").
D. The combined thickness of the separate parts of double or triple monolithic walls shall be not less than that required for single walls, and no single section of a double or triple wall shall be less than four inches (4") thick. The sections shall be tied together with three-eighths inch (3/8") round or square, galvanized or tar-coated rods, with two inch (2") hooks at each end, the rods to be spaced not more than eighteen inches (18") horizontally and vertically.
E. Exterior panel walls supported at each story of skeleton construction buildings shall be not less than five inches (5") thick of reinforced concrete. (1964 Code § 294)