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Stiffeners on bowed plate

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William

I would suggest that unless you remove the bow in these plates that your
new stiffeners should be stiffer/stronger than would normally be required. 
Note that in a previous thread it was pointed out that if you had a stiff
enough brace the member would not buckle.  Thus most criteria is based on
relatively straight members.  This initial bow should suggest that you
re-evaluate the stiffener requirements based the actual  system
eccentricities.

Note that the membrane stresses can only be developed if you prevent the
stiffeners from buckling.

Mark Gilligan


Message text written by INTERNET:seaint(--nospam--at)seaint.org
> 
I am evaluating a square steel bin which was not adequately stiffened, such
that the side plates have bowed outwards considerably (over an inch).  (It
is bowed when empty, i.e. plastic deformation of the plate has occurred.)
The bins have been in use for over 10 years, but the seam welds are
cracking
in some locations.  I would like to add steel stiffeners to the outside of
the steel bin, but I am not sure how easily stiffeners can be fabricated to
match the bowed shape.  Does anyone have advice on how to add stiffeners to
a bowed plate economically?  

I am also curious if anyone knows of a reference for bin design which
considers "large deflection theory", i.e. development of membrane stresses
in addition to flexural stresses in the side plates.  I cannot determine
what the original design of this bin was based on - most of the references
I
have are based on providing stiffeners to control flexure in the side
plates, but one reference states that large deflection theory could be
considered.  


William C. Sherman
Camp Dresser & McKee, Inc.
Denver, CO
Phone: 303-298-1311
Fax: 303-293-8236
email: shermanwc(--nospam--at)cdm.com<