How many times has a contractor called you asking to put heavy equipment on your deck slab?  How confident have you been in your analysis of the deck capacity with these unexpected loads, or have you defaulted to denying these requests to save any headaches over the complex load distribution from the moving equipment?

In the December 2020 SE University session, Mike Antici, PE, from Nucor / Steel Deck Institute, presented Steel Deck Design for Concentrated and Non-Uniform Loads.  Mike explained how to develop simple load diagrams based on the load distribution.  He also explained the limit states for slab design under concentrated loads and reviewed the current and new SDI approaches for concentrated loads.  

After explaining the equations used to determine the sinusoidal moments that develop within overlapping influence zones from multiple loads on a deck slab, Mike revealed the new tables contained in the Second Edition of the Floor Deck Design Manual which can now be used to determine the nominal scissor lift wheel loads for various configurations of deck slabs.  To hear Mike explain the use of these tables along with the assumptions used in their development, click below for a short video clip from his presentation.

These tables will undoubtedly be very useful for the practicing engineer when the contactor calls to request permission to use scissor lifts on the deck slab.  In the past, approximations may have been overly conservative, but with the publication of the second edition of the FDDM, engineers now have the equations they need to determine the available capacity for multiple concentrated loads on their deck slabs.  The Steel Deck Institute has the Second Editions of both the Floor Deck Design Manual and the Roof Deck Design Manuals available for purchase at their website and they both include new design examples and newly developed load tables for concentrated and moving loads.