The axial compressive stress check of the bottom section of the cylinder section failed. Can a section be inserted to strengthen the cylinder?
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A friend asked me to review the drawings. Originally, the main purpose was to see if there were any major problems with the workmanship. As a result, when looking at the equipment diagram, looking at the diameter and thickness of the equipment, I felt that the stiffness was a bit insufficient. So I did the math. . . ……The axial compressive stress of the bottom section of the cylinder section failed to pass the verification, exceeding by more than 31%. After communicating on the phone, they said that the equipment had been manufactured and was still in the processing factory. I recalculated and found that the barrel about 9 meters at the bottom needs to be replaced, and the thickness is adjusted from 16 to 22 (20 is also acceptable, if 20, the relationship between stress/permissible = 105/110, by the way, is it necessary to add some of this margin, and how much do you usually add? ) My advice is, if it's still in the factory, just change it. But think about it, all the internal parts have been installed. Replacing the 9-meter barrel means that all the internal parts have to be reinstalled, and the pre-welded parts may even be partially scrapped. I thought about the possibility of putting a layer of reinforced cylinder on the outside to reinforce the entire circle. Or is there any other way? There are many other problems with this equipment. The number and diameter of anchor bolts are not up to standard. * (We communicated again and were preparing to bury the anchor bolts.^_^, fortunately), the stress of the cover plate exceeded more than 700%, and the rib plate was also unqualified. My friend probably won’t be able to sleep at night :L
This post was last edited by Shutong at 2022-5-14 06:42. Mai Mai first checked whether the strength calculation is correct. Don’t scare your friends: lol There are many factors to consider.: The tower's self-weight, hydrostatic pressure, internal pressure, earthquake, and 0.25 times wind pressure must be calculated, especially the rectangular opening at the bottom of the tower. Normally for large towers, the tower body becomes thicker toward the bottom, and must be calculated in sections. If the strength calculation is correct, the wall thickness of the lower cylinder can be increased during the drawing design stage. But it has already been made. It is wrong and impossible to put a 9-meter section of the cylinder into the cylinder. We should consider setting up a steel structure frame from a certain height for unloading. Do not change the anchor bolts at the bottom of the tower. There are many engineering methods. The calculation should be carried out in accordance with NBT 47041-2014 Tower Vessel and SHT 3098, but the simple and reliable calculation for engineering is to use ASME
The calculations have been checked repeatedly. Moreover, the height, diameter, and wall thickness of the lower section of the tower are a bit worrying at first glance, otherwise I wouldn’t have calculated this thing. I don’t know how they passed the review during the design stage.
This post was last edited by yyong110 on 2022-5-15 18:42. My editor friend asked the processing plant to perform an inspection himself. It is said that the processing plant himself broke out in a cold sweat after the inspection: L:L:L Let’s discuss what will happen if this tower goes up and a strong wind blows. What responsibilities do Party A, the designer, and the processor have to bear respectively?
The anchor bolts, skirt cover plate and backing plate can be changed to Q345R, and the thickness of the backing plate can also be changed to the same thickness as the cover plate. The thickness of the tower body is calculated as much as it is.
This post was last edited by yyong110 on 2022-5-18 09:34. There are too many differences. The diameter of the tower is small and the quantity cannot be increased. Later I asked them to change the anchor bolts to 35CrMoA and the cover plate to 60mm, Q345R. They didn't design it well at the beginning, and now they are very passive. But there is no choice but to change it. It seems that the support ring of the replacement cylinder body has been welded, and all of them have to be cut out and remade. No one wants to take risks on this kind of thing. All I can say is that the designer is fucked.
What I'm talking about is just to improve the stress situation. If that still doesn't work, you can also change the skirt to a tapered shape. I have never heard of 35CrMoA being used for anchor bolts. If you can't change it, there's nothing you can do.
I also saw this material option in SW6, so I recommended them to choose it. In the past, it was usually Q345R at most. The diameter rarely exceeds 64. This time, they either chose M85 with an exaggerated diameter, or upgraded the material to 35CrMoA. The other screwdriver-shaped skirts, equipment, and civil engineering have also been completed, and the amount of modification work is larger.
Just release some of the safety margin. It's a matter of security level. The outer hoop is made into a composite plate-like structure. Or make reinforcements.
Let's consider seismic and wind loads differently. Software calculations must also have correct input.
Looking at the calculation results, your tower is at least fifty or sixty meters high. Aren't these towers usually placed in a frame?