Help needed! When a flat cover welded to the bottom of a storage tank is placed in direct contact with the foundation, isn’t it unnecessary for the cover to be very thick?
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This post was last edited by WallaceLee on 2020-7-31 at 14:22. As shown in the diagram, a storage tank is being designed in which the bottom of the tank consists of a welded flat cover; the tank does not require any bottom supports or legs, as the welded flat cover at the bottom is placed directly on the foundation. As shown in the figure, this is an ASME vessel. When designed using PVELite software, the thickness displayed for the \"calculated thickness for internal pressure\" of the welded flat lid Tr at the bottom of the screen is 52 mm. The thickness of the cylindrical shell and the cone tip under internal pressure is 6 mm. My question now is: when a storage tank does not require bottom supports or legs, and instead its bottom flat cover is welded directly to the foundation, is it really necessary for the thickness of that bottom flat cover to be so large? Should it be about the same thickness as the cylinder?
This post was last edited by wx_Catherine_Mi on 2020-8-3 10:22. From what I’ve seen, this type of structure with atmospheric pressure is common; cones are generally not used when high pressure is involved. It can’t be this thick. Let me give you an example: a diesel storage tank with a design pressure of 0.006 MPa, an inner diameter of 4 meters, and a height of 6.9 meters. The thickness of the tank walls and bottom is 8 mm; the top should use a weakly connected structure with a thickness of 6 mm, as specified in GB/T50341. I hope this helps you. If there are any mistakes, please feel free to point them out; I’ll learn from them as well*.
This post was last edited by wx_Catherine_Mi on 2020-8-3 10:22. How did it turn into two posts?
My work mentor said that for storage tanks with a flat bottom cover that is placed in direct contact with the foundation, such a thick cover isn’t necessary since one end of the flat cover is in contact with the ground and the internal pressure at the other end counteracts that force. Yet the software calculates a thickness of this kind; I’m not sure why. Does that mean the thickness indicated by PVELite can be ignored?
This post was last edited by wx_Catherine_Mi on 2020-8-3 11:04. Sorry, I’ve never used PVELite; I had the chance to learn it before but missed that opportunity. As far as I can see, it’s really not necessary. You can also take a look at the \"Atlas of Dome Tanks\" – for flat bottoms, the thickness is usually the same as that of the walls; at most, it can be increased by 2 mm. For example, if the wall thickness is 6 mm, the bottom thickness can be increased to 8 mm. Your teacher is right. As for how to deal with it, you can ask him, or you can check your calculations to see if there’s any mistake.
Thank you very much for your reply! ! Learn together * Progress together! :D
You’re welcome; let’s learn together and make progress together.
Just refer to the atlas; it can be slightly thicker than the atlas. All these software tools are useless for this purpose. I specialize in tank design – if you have any questions, contact me privately at 18877229966, Manager Zheng