Api 650 Anchorage requirement

[Anand23404]

Hi there!
Greetings..
I am designing a tank for worst seismic zone and having Dia=20m & Ht.= 18m (liquid ht=17.5). Through the calculation , i am getting the Anchorage ration, J= 3.8 and therefore Anchor bolt size is coming out to M56 (36Nos.).
The requirement is quite high and i am not sure about it. Please guide me if It is okay to have such a large size of bolts.
regards

 

[JStephen]

Yes you can come up with a lot of bolts. In that case, it may be advantageous to make the tank wider and lower.
It may be possible to use larger bolts and fewer of them, or higher strength bolts. It will depend on shell thickness and other factors.

Usually, where anchorage is coming up very high, the sloshing wave height will be fairly high, so you may need additional freeboard.