scaffolding design - what loads to use

huangyhg

scaffolding design - what loads to use?
i was wondering if someone can help me figure out the correct design live loads to use on a scaffolding system that i have to design.  i have a 10ft wide sidewalk shed level (1st tier) supporting (5)-6ft wide levels of scaffolding above.
the latest njibc (section 3306.7) lists a 150 psf design live load for covered walkway which i'm taking to be at the sidewalk shed level.  then osha (section 1910.28) lists the upper levels to have a design live load of 25, 50 or 75 psf depending on whether they are considered light, medium or heavy duty use.
my questions are as follows:
(1) are these loads correct? if not, what values should i be using and where could they be found (code, etc...)?
(2) should the upper (5) levels be loaded simultaneously or just one or two at at time depending on the contractors use? i tried a preliminary run with all the levels loaded (sidewalk shed + scaffolding tiers) and am coming up with crossbeams being much larger than what i typically remember walking under scaffolding systems.


what is the scaffolding going to be used for?  you should have an idea of what the construction load would be, ie. cubes of brick, buckets of plaster, bags of cotton balls, etc.  then, how much will be staged in a given area.  from this, and with a fos incorporated in, you can come up with a design load.  i am not sure you will find a general design load for scaffolding anywhere.  even if you could, i would figure out the intended use and make the comparison.
i've always seen 50 psf loading for construction.