New materials and methods of design and construction have been developed in the past 10 years that required new code provisions. This has been particularly true of reinforcing steels. The important properties of the new reinforcement is recognized in the 1963 Code. How will the utilization of these steels affect designs? The 1963 ACI Code separates design into two methods, ultimate strength design (USD) and working stress design (WSD). Working stress design is the conventional method. With ordinary concrete, any steel in standard size bars (up to #11), and a working stress of 24,000 psi or less, the previous design procedure is essentially unchanged except for shear and bond. Our usual standard details apply except for splices, end anchorage, and edge beams wit torsion., Even under the 1956 ACI Code there was a need for special details when 75,000 psi yield strength bars were used in columns, and all lap splices of special 14S pound or 18S pound were not covered. Tension lap splices of 14S pound and 18S pounds bars are now prohibited entirely, and welded or mechanical splices are required. Such splices are also preferred for compression, although bars not required to carry tension may be spliced by endbearing. The detailed provisions must be shown on design drawings and in specifications and never left to the detailer. Ultimate strength design was first recognized in the 1956 Code, but no specific procedures for design of connections and details were included. This deficiency is remedied for the most part in the 1963 ACI Code. In order to utilize properly yield points above 40,000 psi the new code provides for more than proportionately longer splices and anchorages. The designer is almost compelled, in any cast in place construction, to stagger splices. He is encouraged to enclose splices by closed ties or spirals. He is required to use mechanical connections or to weld all tension splices of 14S pound and 18S pound bars. The 1963 Code states that splices in tension in flexural members must be "fully developed" and shall transfer the entire stress from bar to bar. This ambiguity is a holdover form the 1956 ACI Code. Welded splices and mechanical connections must develop a definite 125 percent of the full specified yield point of the bars or an additional 25 percent bar area must be provided.