"Joe" wrote in
message roups.com...
The width is 60 feet and the height is 20 feet in the center .. The
load
will be spanned 2 feet in the top center of the arch. If tube is
not bent
, it can be welded every 10 feet of the arch and a piece of flat
strap
welded to butt welded joint to strengthen to joint. We are actually
trying
to support something 2 feet wide by 30 feet long weighing 1300
pounds. The
arched tubing will be fastened to a roof above which will not allow
it to
shift. I want to support the 1300 pound weight sitting on the arched
steel
roof above. The arched steel roof already exists, I just want to add
arched steel support underneath. I do not want to use any of
existing roof
to support weight because I want to maintain prior engineered snow
loads.
I can bolt into roof to reduce shifting The roof is 18 gauge steel,
int
the shape of described arch. The base if the new support arch of
2"x6" ?
Square tubing can be anchored in to cement at ends by use of steel
plating
and anchor bolts.


To narrow your search, look into truss design and column buckling
strength, the "column" being the long truss components.
http://en.wikipedia.org/wiki/Buckling