scope:

The use of "tapered structural elements," having tapered depths and/or widths, was first proposed by Amirikian(1) for reasons of economy in 1952. In view of the lack of basic understanding of the behavior of these types of members, in particular the lack of information having to do with design against instability, the Naval Facilities Engineering Command, the American Institute of Steel Construction, the American Iron and Steel Institute, and the Metal Building Manufacturer's Association have jointly sponsored since 1966 a research project at the State University of New York at Buffalo to carry out such studies. As part of those studies, both analytical and experimental investigations were conducted on the behavior of such tapered members and the results were used to develop proposed design formulas. This paper, which summarizes many of the conclusions of those investigations, is concerned primarily with (a) the overall. analysis of tapered member framing, and (b) the development of the design formulas regarding the proportioning of tapered members. A general treatment for any arbitrarily tapered beam would be very ambitious and, in general, impractical due primarily to the difficulties associated with the coupling of flexural and torsional deformations. For this reason the most common tapered I section now being used was chosen for examination, and design formulas for such members were developed. It is to be recognized, however, that the formulas suggested may also be applied (with caution) to other sections which are "sufficiently braced" to prevent torsional deformation.