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Impact Load on a Composite Deck

Impact Load on a Composite Deck

Impact Load on a Composite Deck

(OP)
Trying to determine if a composite roof deck (3" W Deck with Lt. Wt. Conc. fill) can withstand the impact of a piece of equipment dropped from a certain height in the event the crane carrying the load fails. Any relevant design equations?

The current methodology I am using:
Currently I have determined the amount of energy that would have to be transmitted into the deck with gravitational potential energy:
PE=mgh
Assuming that energy will do work on the roof deck when the equipment impacts the deck, it will cause a deflection, x, on the span deck dependent on the decks stiffness, k:
PE=0.5kx^2
But I don't know how to determine what the stiffness of the deck would be or the maximum allowable deflection, x, of the deck would be.
Any guidance?

RE: Impact Load on a Composite Deck

If you have lightweight structural concrete and not lightweight insulating concrete, the concrete will absorb the dynamic load based on its stiffness. Neglect the deck for conservatism. If lightweight insulating concrete, neglect the LWIC and consider the deck stiffness.

RE: Impact Load on a Composite Deck

The way many codes deal with this is to simply apply another dynamic load factor on the impact load and then normal checks follow as a matter of course. The dynamic modulus of elasticity is sometimes also taken as a higher value under dynamic /vibration checks (usually 1.35 times the typical value.

RE: Impact Load on a Composite Deck

Quote (Ron)

Neglect the deck for conservatism.

Similar to Ron's suggestion, SDI recommends ignoring the contribution of the deck for dynamic loads.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

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