wo steel plates

huangyhg

two steel plates
i know this should be be a problem that has been addressed before...but i've looked at numerous books and posts and can't seem to find a solution.
i have and opening to be covered by 1-inch thick roadplates.  but a single 1-inch plate will be overstressed.  we could lay two 1-inch thick plates over the trench but how do i calculate the capacity of the two plates? i know the two 1-inch plates have less capacity than one 2-inch thick plate.
two 1" thick plates are simply twice as strong and twice as stiff as one 1" thick plate.
daveatkins
bingo -
dave is right on
thanks guys.  i've been mis-informed all these years.  i always thought that because the plates were not physically connected that strength and stiffness is less. thanks again!
it is less than a 2" thick plate, however 2 each one inch thick plates are exactly twice as strong as 1 each one inch thick plate. (a 2" thick plate is four times stronger than a 1" thick plate in bending).
rpizzi-
everyone else has covered it, but for what it's worth......... two members over top of each other but not acting compositely is identical to the two members side by side sharing the load instead of one member.  think of it as doubling b instead of h in the (bh^2)/6 for s