Deformation and strength of tank bottom
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Please ask: GB50128 Article 6.3.2: After the tank bottom is welded, the depth of its local concave and convex deformation shall not be greater than 2% of the deformation length, and shall not be greater than 50mm. How to understand? If the bottom plate has a convex deformation of 40mm on a length of 2000mm, will the bottom plate not tear after being stressed?
It is easy to understand. For example, if the concave and convex are 10mm, and the total deformation length here is 1000mm, the depth of the local concave and convex deformation is 1% of the deformation length, which does not exceed the standard. For irregularities that exceed the standard, methods such as cutting plates or opening holes and filling them with sand should be adopted. Otherwise, if the tank is operated for a long time, the welds at the deformed parts may fatigue and crack.
The poster is very good at picking out words. This is the minimum standard required by the specification. Of course it will not tear. The poster, if you are in the construction unit, you will understand.
This sentence can be understood like this: The local concave and convex deformation within a radius of 2000mm, that is, the height difference between the highest point and the lowest point within any diameter of 2000mm at the bottom of the tank, is qualified if it is less than 40mm, and is not allowed if it is greater than or equal to 40mm.
Thank you, Floor 4. I originally understood it as deformation in a single direction. I took a long strip and calculated it as a simply supported beam. The stress exceeded the allowable value. I'll do the math on the round plate again.
According to the explanation on the 4th floor, I performed calculations based on the model of a circular flat plate with perimeter hinges and perimeter fixation. I found that when the liquid level is high and the deformation caused by the water pressure has not yet reached the allowable value of the specification, the perimeter stress has already* * The yield limit of the material has been exceeded. So, I wonder what is the basis for the specification to limit this deformation? Is it based on experience or is there something wrong with my calculation methods and ideas?
In fact, the specification should be the minimum requirement! ! Standards for general use are higher than this! !