The International Information Center for Structural Engineers

Seismic design of composite metal deck and concrete-filled diaphragms - A discussion paper

K.A. Cowie,A.J. Fussell,G.C. Clifton,G.A. MacRae,S.J. Hicks.
Book Title or Journal
New Zealand Society for Earthquake Engineering - Annual Technical Conference
Number of pages
One of the most neglected elements in the design of buildings is the horizontal floor diaphragm and its interaction with the lateral load resisting systems. Most multi-story structures depend on the floor slab and roof systems to act as horizontal diaphragms to collect and distribute the lateral loads to the vertical framing members, which provide the overall structural stability. In steel structures, floor diaphragms are most commonly constructed using composite steel deck with concrete fill, although other systems may also be used. Somewhat surprisingly, given the importance of diaphragms to the overall building response, there is no universally agreed design procedure for determining the diaphragm actions and distribution into the seismic-resisting systems. In addition, the specific issues related to beam design for members collecting lateral loads in composite floor systems has gone largely undocumented. This discussion paper presents a suggested method in determining the design diaphragm actions at a given floor level, how to proportion their transfer into the seismic resisting systems and how to design and detail the supporting beams/composite metal deck for these actions.
composite deck,diaphragm