Elon NC Students ‘Break Dance’ on Floor Trusses

Originally published by the following source: SBC MagazineOctober 14, 2019
by Sean Shields and Kirk Grundahl, P.E., contributions from SBCA Professional Engineering Staff

   

Editor’s Note: A special thanks to Mark Rolf of Trussway for providing ongoing market intelligence feedback on student housing floor performance.

When large groups of students gather and dance, it can create loading conditions neither intended nor anticipated by the building designer. While a recent floor collapse at Clemson University is a prime example of this phenomena, a more recent three-inch floor truss deflection at Elon University in Elon, North Carolina is also instructive.

On August 31, 2019, a group of students at an apartment complex near campus were hosting a large dance party. As can be seen in the video at right, the apartment was packed with students.

One eye witness estimated that at least 100 people were at the party. At some point during the party, the floor system experienced abnormal deflection and “sponginess.”

According to an interview with the apartment management (video below), the tenants woke up the next morning and noticed the floor was “out of shape and may have dropped three inches.”

Those observations prompted the management company to conduct an intrusive inspection, as can be seen in the photograph below.

Given the rise in buildings being built for student housing, and the increased potential for high occupancy and rhythmic dancing loading conditions, it is wise for component manufacturers to reduce the potential for “back charges” with request for information (RFI) documentation, which we outlined in a recent article.

It is very important for all construction professional involved in student housing projects to clearly define the approved floor loads. Here is an example RFI table CMs could use to confirm design load conditions:

Loads to be Modified Per Plan Condition Applied To
____psf 40 psf Live Load Living Top Chord
____psf 40 psf Live Load Corridor Top Chord
____psf 100 psf Live Load Public & Lobbies Top Chord
____psf 27 psf Dead Load All Interior Top Chord
____psf 50 psf Dead Load Exterior Terrace Top Chord
____psf 0 psf Live Load All Conditions Bottom Chord
____psf 3 psf Dead Load 1 hr Ceilings Bottom Chord
____psf 6 psf Dead Load 2 hr Ceilings Bottom Chord

Having an RFI reviewed and confirmed ensures that the owner, building designer, general contractor, component manufacturer and framer know that the occupancy conditions surrounding student housing have been considered and the assumed design loads, as defined in the original plans and specs, are either modified or accepted as defined in the original plans and specs.

For additional information, please review the following resources and articles on collapses due to overloading by crowds:

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