Many engineers consider rectangular structures with light gauge metal deck diaphragms unstable if they are laterally supported on only three sides. Given the standard assumption that light gauge metal deck diaphragms are completely flexible, this type of structure, often referred to as a 3-sided box, would be unstable. While this assumption is often useful for diaphragm design, it is not strictly true. Light gauge metal deck diaphragms have stiffness, and 3-sided box structures are stable when designed properly. A design method for this type of diaphragm was introduced in the Steel Deck Institute’s Diaphragm Design Manual (DDM) 2nd Edition in 1995. Since then, many single-story structures have been designed using this method, demonstrating its validity. Additional information can be found in the current DDM 4th Edition in Section 10, Example 7.
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Author Archives : Jim Lintz, P.E., S.E., LEED AP BD+C
Jim Lintz is a Structural Engineer at LJB Inc. in Dayton, OH. (jlintz@ljbinc.com)
There seems to be a lot of angst among structural engineers about our profession, a general notion that we do not get the credit that we deserve or the proper amount of respect from the public. It is as if we work in the Rodney Dangerfield of professions, “I don’t get no respect.” However, having recently read Samuel C. Florman’s book, The Existential Pleasures of Engineering, first published in 1976, it is clear that our concerns for our profession are not new. Many of the concerns Florman had 44 years ago continue to this day, such as not attracting enough of the best and brightest students, engineering education being too technical, lack of passion for our work, lack of exposure for engineers in popular culture such as novels or movies, and not getting the same respect as other professions. Since then, other concerns have developed, such as not retaining talent, not adopting new technology quickly enough, and being replaced by technology.
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