Columns in Planar Continuous Structures

A design method for steel columns as parts of a continuous frame is developed. For the design of each column, only adjacent members are assumed to provide restraint. Therefore, the column is designed as part of a subassemblage. The design is based on the ultimate strength or limit of stability of the entire subassemblage. This will usually be in the inelastic range. A check for adequacy of a column cross section as part of a subassemblage is developed. This check for adequacy has the function that the AISC interaction formula has in conventional design. The only mode of failure designed for is instability due to bending in one of the principal bendin planes. The charts and example are for the case where the column will be bent in syn metric single curvature, but the method can be extended to other cases. The design method has evolved as one of the preliminary stages in a research project being conducted on the plastic design of multi-story frames.