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Heavy concentrated dynamic load on slab

Heavy concentrated dynamic load on slab

Heavy concentrated dynamic load on slab

(OP)
Good afternoon!

It is necessary to put car jacks on a composite slab. The slab is multi span and is over secondary steel beams spanning 1.7m.
The composite slab consists of a steel decking panel, and a reinforced concrete of 100 mm height counting from the top of the decking panel's rib.

Except from distributed loads, I have a concentrated load of 30 kN, which is also dynamic.
Do you think that it is possible to design such a slab?



Thank you,
Davit Sh

RE: Heavy concentrated dynamic load on slab

Well, "nothing" is impossible in engineering. You could design such slab, but you have to consider a lot of effects. Check whether there are any punching issues (if the concentrated load is distributed over a small area). Also, I would recommend checking the global behavior of the structure. Since dynamic loads are included, I think you need a specialized software to help you (Sap2000 maybe sufficient). I would worry most about vibrations, which are quite difficult to predict analytically (in my opinion and experience).

p.s.: I did not check you image thoroughly, so please consider my comment as "just a general guide".

RE: Heavy concentrated dynamic load on slab

(OP)
Thank you. Well, I should have stated vibrations instead of dynamic behavior. I am able to design it sufficiently. But I am afraid I will not be able to consider analytically the vibrations. That is what worries me the most. I feel like no matter how strong I design, it will crack at service stage.

RE: Heavy concentrated dynamic load on slab

There has been doubt expressed about the strength of metal deck composite slabs under point loads.

Most of the testing to determine bond and slip resistance have been done assuming UDL loads which give a gradual change in stress and therefore bond requirements. Point loads will cause a much more severe change in bond requirements and may result in reduced boned and thus strength. You would need to make sure that the slip model you are using has considered this.

RE: Heavy concentrated dynamic load on slab

In the UK at least, manufacturers of this type of decking have produced their own software which allow you to input additional loads like the one you mentioned above. A lot of their capacities and span tables are based on test data, in particular longitudinal shear capacities, so I would definitely see if the manufacturer you have in mind has something like that before creating any models yourself.

RE: Heavy concentrated dynamic load on slab

Completely ignore the metal deck contribution to strength and stiffness for this analysis

RE: Heavy concentrated dynamic load on slab

I agree with atse.

Also a note...i see you have 3 layers of rebar. Imho middle layer is unecessary.

RE: Heavy concentrated dynamic load on slab

(OP)
Yes, I did ignore it.
Actually I removed it already. This type of slab is new to me. Thank you

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