Direct Design of Framed Structures

A general systematic procedure for the design of structures is presented, and its application to framed structures is outlined. The problem is defined in such a way that the required proportions become the dependent variables for which the solution may be determined from the design criteria: Required behaviors in terms of stress, strain, or displacement, at the various loadings involved; minimum weight or minimum cost; and conventional constraints imposed by the site, the codes, or the function of the structure. Particular cases considered are a multistory metal frame, and a prestressed concrete frame in each of which geometry is considered fixed. For the metal frame the behavior criteria introduced are: The degree of interaction of moments between the beams and columns, and elastic or inelastic failure criteria for each. In a prestressed concrete frame, additional criteria may be satisfied allowing the tendons, also, to be completely determined. That the procedure described leads directly to the automation of the design process is noted.