Friday, April 10, 2009, 2 PM
Olsson Hall 120

Design of Thin-Walled Cold-Formed Steel Structural Members with Perforations

Dr. Cristopher D. Moen

Abstract

In this presentation, the development of a general, mechanics-based design method for cold-formed steel structural members with holes will be discussed. The new design method is currently being integrated into the American Iron and Steel Institute's North American Specification for the Design of Cold-Formed Steel Structural Members. Thin-walled cold-formed steel (CFS) structural members are commonly manufactured with holes to accommodate plumbing, electrical, and heating conduits in the walls and ceilings of low and mid-rise buildings, although current design protocols available to engineers are prescriptive and limited to specific perforation locations, spacings, and sizes.

The new design method predicts the ultimate strength of a general CFS column or beam with the elastic buckling properties of the member cross-section (e.g., plate buckling) and the Euler buckling load (e.g., flexural buckling) including the influence of holes. This presentation will start off with fundamental studies on the elastic buckling properties of rectangular plates and cold-formed steel beams and columns, including the presence of holes. From these initial studies, simplified alternatives to FE elastic buckling analysis for practicing engineers are introduced, and the results of experiments on cold-formed steel columns with holes are used to demonstrate interaction between elastic buckling, load-deformation response, and ultimate strength. The development of a nonlinear finite element protocol to simulate loading to collapse of cold-formed steel beams and columns with holes is discussed, and finally the design equations relating elastic buckling and ultimate strength for cold-formed steel members with holes are introduced.

The Civil Engineering seminar series is open to the University community.
Civil Engineering undergraduate students are especially invited to attend.