floor plates

huangyhg

floor plates
any great online references out there on the design of floor plates? i am going to have a steel floor plate spanning 5 m on one side, and 21 m on the other.
a very very simplistic approach that i have on mind in determining the plate thickness is finding the moment from the uniform pressure (wl2/8) and plugging it in the stress = my/i and solving for i and subsequently the thickness. i know there is much more to this than that, but i can not seem to find any information on the texts that i have in my possession.
i want to steer away from fea for this and stay with hand calculations.
also, for the gratings, does the design engineer design it or is it usually ordered from a specialized fabricator for gratings?
thanks
i think your wl^2/8 approximation would be reasonable for a constant thickness plate in this case as the width is much greater.
i would question the use of a constant thickness plate for something this large though. i would suggest some stiffening beams at say 2m apart.
deflection is always critical for steel plates.
roarks stress and strain is good for this.
csd
we always spec the grating in our drawings.
i am interested in knowling why do you want to use a constant thickness plate for 20m span.  i would suggest to use beams with corrugated metal deck.
if steel plate is your final selection, you can read "plate and shell" by timoshenko.  this is a classical text book and solves everything by hand.  you can simply use the eqations in that book.  yield line theory (energy method) is also handy for your hand calculations.
for grating, we always spec it in our structural drawings.  what you need is to find a grating company online and find the right size to spec it.  some companies also has existing spec for you to copy.  try this  
i designed a floor plate system once.  i can't re  
the thickness of the plate to span 21 meter is unworkable for deflection and not economical compared to welded stiffeners attached to the bottom.  try 500mm deep channel welded at 800mm spacing.  try 20 mm plate.
i think he means a 20x5m plate supported on 4 sides. the span is then 5m not 20.
csd