Tank Internal Supports

[butelja]

I am designing internal supports for a large bayonet heater that will be installed in an API 650 oil storage tank. Due to thermal expansion, the heater will have to slide over the supports. It is desired to NOT have cross bracing between the internal supports to resist the lateral loading caused by thermal expansion.

My question is, how can I evaluate the bending stresses (without FEA) in the floor plate caused by the lateral support loading? Consider the floor plate to be of infinite size and continuously supported from the bottom. We want to keep the bending moment from lifting the floor plate or locally overstressing it.

 

[Tankman650]

Typically I don't like to place any loads directly on the 1/4" bottom plate. The pull through or punching loads may damage it. Try welding a large and thick reinforcing plate on top of the bottom plate to spread out any concentrated loads.

 

[butelja]

Tankman650,

Thanks for the advice. This particular tank is relatively small (23 ft diameter) and sits on a concrete foundation, to I don't think punching loads are an issue. Also, the original bottom corroded and was replaced with 1/2" bottom plate. I think I'll still use repads to spread the load.