Insufficient number of dynamic modes when thawing water tank

[gunner]

Hello. I am trying to model a water tank for the first time. The biggest problem I encountered was to increase the number of mods up to 180. Is this normal for a small water tank? though it has a size of 20 meters by 4 meters. Height at 3 meters. other than that, I had to remove the raft foundation by 70 cm for the water tank. I hope there is no mistake in the installations I have made on curtains and raft flooring. I am sending the project link so that I can get your advice, which is of great importance to me.

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[Levent Özpak]

hi.... I am trying to model a water tank for the first time. The biggest problem I encountered was to increase the number of mods up to 180. Is this normal. Apart from that, the raft foundation for the water tank is about 70 cm I had to remove it. I hope there is no mistake in the installations I have made on curtains and raft flooring. I am sending the project link so that I can get your advice, which is of great importance to me.

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Hello, *It is normal that more modes are needed to ensure sufficient mass participation rate, since analysis is made according to the semi-rigid diaphragm option and response spectrum. (If the calculation is made according to the fully rigid diaphragm and mode combination method, 3 modes will be sufficient.) *If you made the raft slab 70 cm due to the minimum thickness warning, the distance between the columns for the clean opening value (Ln) in the raft slab thickness control. e is being looked at. With the "Reinforced Concrete Calculation Axis Edit" command, the value of the reinforcement axles -clear clearance for thickness control- can be intervened. -A horizontal load is defined on the curtains under Q loading from the inside to the outside. (I think it was defined for water.) It would be appropriate to define this load by creating a separate loading situation and loading combinations within the framework of the conditions specified in TS 500 article 6.2.6 e. Good work

 

[gunner]

Hello, *If you made the raft flooring 70 cm due to the minimum thickness warning; In the raft slab thickness control, the distance between the columns is checked for the clear span value (Ln). With the "Reinforced Concrete Calculation Axis Edit" command, the value of the reinforcement axles -clear clearance for thickness control- can be intervened. -A horizontal load is defined on the curtains under Q loading from the inside to the outside. (I think it was defined for water.) It would be appropriate to define this load by creating a separate loading situation and loading combinations within the framework of the conditions specified in TS 500 article 6.2.6 e. Good work

was defined for Q loading for water as you said. I will change it now. Thank you very much for the reply.

 

[NYILMAZ]

I would like to add a sentence or two in terms of design. Considering your dimensions, 20x4x3= means a warehouse of approximately 240 m3 (or tons). If it were me, I'd at least break it into 3 parts. In this way, you do not make a one-piece curtain with a length of 20m, and you provide additional connections with vertical curtains at certain places (for example, at 5m intervals). In addition, when it comes to cleaning, breakdown, maintenance, etc., you do not have to empty the entire 240-ton warehouse. I think it would be more logical to make 3-4 eyes connected to each other. It will also be beneficial if you can carry the raft floor to the outside of the walls, if possible, and make it cantilevered.