impact forces

huangyhg

impact forces
for impact produced by some loading on a concrete floor, how far should you take it? obviously you should include it for the slab design. how about the beam supporting the slab? how about the girder supporting the beam? i would think that you need not carry the impact into the column since the increment of impact would be very small compared to the total load it would normally carry.
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good question. imho, since aisc (ninth edition) has provisions for impact loading, i would make sure that at least one level of steel   
i would consult with someone familar with aashto code, as the impact load is an indispensable part of bridge design.
for bridge design aashto basically requires you use the impact load on all above ground portions of the structure.  for example, impact load on a deck would be included on the supporting beams.  and if the beams were supported by a pier or such that element would also be designed for the impact load.  the impact load would not be used for the foundation design though.
this may be conservative, but aashto design requirements are typically more conservative than aisc.
i have no building design experience, but i would suspect it would be reasonable to take the impact up to, but not in to the columns (i.e. into all   
hi jike,
i believe impact for buildings is related to live load and the associated minimum loadings for various uses incorporates the effect of vibrations from these live loads.
i have not encountered impact for buildings similar to impact for bridges.  anti-terrorism may change that all.
vod