huangyhg

slab design technique
please, i need some hints on slab designing using staad.pro. i have a 6m by 7m area of concrete slab with loads of 3.6kpa for liveload. i got confused with the results, it has a top and bottom reinforcements unlike in the conventional way where the bars are arranged in straight and bend scheme. please i need some advise and techniques and some explanations in the simplest form. thanks. 3eyes.
why don't you use hand calculation to check your staad result. could you give more detail about your structure? what do you mean when mention "... unlike in the conventional way"?
thank you for your valuable tips. i mention "unlike in the conventional way.." i mean the basic manual calculation...i'm trying as much as possible to have all my design fully aided with computers though it is necessary sometimes to do manual calculations.
slabs can be designed using the software staad.etc, which gives the design results, calculations and reinforcement drawing.
nazareno
i guess i am not sure what kind of slab you are wanting to design, is it a two way or one way? support condition? loading condition? because, the older version of staad pro, (i.e., not staad pro 2003) does not design two way slab in accordance to aci. it only takes the moment/ft can calculate the req'd reinf. therefore, if it is a two way slab, you should use the 2003 version or use the moment by staad and hand design the slab, so that you could design it to comply to the code.
it is important to take care designing slabs with staad. as far as i know only flexural loads are taken into account to calculate reinforcement in each direction but membrane forces are ignored. what i do in this regard is to take forces from the element stresses output and calculate by myself reinforcements taken into account membrane forces.
two more things:
forces are given by surface unit.
forces are given in local coordinate system.
if using staad.pro 2003, two-way slab design is done using the column-strip method. you can draw your own zones/panels or the program can do it automatically. it provides reinf contours and reinf diagrams as well. it takes into consideration membrane forces including mxy (wood-armer).

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