huangyhg

openings in cylindrical shells
i am seeking advice on the design of a handhole opening in a round steel column used to support an overhead sign. biaxial bending, axial compression and torsional forces are applied.
the client wants a 6" x 8" handhole placed in an 18" upright, near the column base. the 6" dimension is along the circumference, and the 8" dimen is along the axis. the hole will be capsule shaped (i.e., 3" radii)
i've seen other details where the edge is reinforced using a metal plate, full pen welded all around.
any ideas where i can find a good reference or design example for this problem?
thanks for your valued assistance!
check out the american petroleum institute's publication api 650. the situation described appears to be similar to a nozzle penetration in a fuel tank.
the basic principle for reinforcing such an opening is to replace the area of material lost due to the cutout. for example, for a 6" diameter cutout, the reinforceing plate will typically be twice the diameter of the hole. the reinforcing plate will be the same thickness as the material removed.
consult aci650 for additional information.
look up your state highway department website. they often have standard designs for overhead signs. the detail you're asking about is pretty standard. unfortunately, the one i was familiar with (arizona) took the details off their site, so now you have to buy them.
thanks for everyone's comments & advice.
while our local dot does have details for reinforced handholes, they are typically used for signal and lighting masts. the bending and torsional forces are much greater on the sign structures.
regards, raf

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