huangyhg

do you include concrete floor in modeling a building?
do you model the cast-in concrete floor in the calculation of buildings?
if so, please give the element type and modeling techniques you use.
if not, please specify the way you determine the loads transferred to surrounding beams.
discussions will be based on sap2000, etabs or staad pro.
imho, you should model concrete floors as, due to their inherent stiffnes, will provide diaphragm action aqnd thus reduce the overall displacement of the frame.
i have no experience of the programs mentioned but if they are any good they should have the ability to model a 'stiff deck' or be able to apply the actual element type.
i ahve experience of masterseries and cads a3d both of which have this feature.
any other suggestions?
i have conducted some test samples in etabs and found the floors (area objects) need not be meshed if they are modeled with plank or deck, which transfer vertical load to surrounding beams sigle way. however if you model the floors with slab and do not mesh the area objects and surrounding beams, the results of the beams are not correct. do i have to mesh or slab area objects and surrounding beams before i run the analysis? if so, the number of elements and the calculation time would increase considerably.
can anyone that have pragmatic experience in these software give me some suggestion?
in etabs,
first you have to assign to the floor element a slab property with plate specification. to obtain moments in adjacent beams, you have to do manual meshing at the very end just before you are ready to run the calculations.
v2
in staad 2003, they have a new feature that will automatically transfer the loads from the plates to the beams without having to increase the size of the model. dont need dummy plates.
thanks guys. i have found that you can define the meshing property of area objects before running the analysis in etabs and sap2000. by doing this one can get the right result in surrounding beams without having to mesh every slab manually.

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