Uplift from wind and Overturning - Anchorage
Uplift from wind and Overturning - Anchorage
(OP)
Gentlemen,
A. How to apply 5.2.1.j.2?
1. Calculate value for F.4.1
2. Convert F.4.1 * 1.6 to moment
3. Calculate moment resulting from pressure Mpi 5.11.2 (could be zero)
4. Calculate moment from horizontal wind
5. Calculate moment from vertical wind - but not greater than (moment from F.4.1 * 1.6 - Mpi)
6. Add moment from horizontal wind and lesser of vertical wind or (moment from F.4.1 * 1.6 - Mpi) for Mw
If this is not how to apply 5.2.1.j.2, then how is it applied?
B. What do you do with the negative number from F.4.2 on large tanks when all other values calculate positive?
Thanks!!!
A. How to apply 5.2.1.j.2?
1. Calculate value for F.4.1
2. Convert F.4.1 * 1.6 to moment
3. Calculate moment resulting from pressure Mpi 5.11.2 (could be zero)
4. Calculate moment from horizontal wind
5. Calculate moment from vertical wind - but not greater than (moment from F.4.1 * 1.6 - Mpi)
6. Add moment from horizontal wind and lesser of vertical wind or (moment from F.4.1 * 1.6 - Mpi) for Mw
If this is not how to apply 5.2.1.j.2, then how is it applied?
B. What do you do with the negative number from F.4.2 on large tanks when all other values calculate positive?
Thanks!!!





RE: Uplift from wind and Overturning - Anchorage
good luck!
-pmover
RE: Uplift from wind and Overturning - Anchorage
RE: Uplift from wind and Overturning - Anchorage
B. From F.4.2 it would appear that when this formula yields a negative result that the tank has no additional capacity for uplift due to internal pressure. In fact, it could be viewed to indicate that the tank requires anchorage simply due to the wind moment, and if the tank were to be anchored this would make F.4.2 n/a and you would be referred to F.7. I have not analyzed the corelation (if any) between F.4.2 and 5.11.2, but it could be an interesting exercise.
RE: Uplift from wind and Overturning - Anchorage
I think we are essentially doing the same thing. If there is no pressure on the tank, F.4.2 does not enter into the calculation. Where there is pressure, if this limit is not applied, there is always a negative value. In the designs I have done recently using the limit, F.4.2 does not calculate a negative number although the amount of pressure allowed is extremely small. I think your method may be simpler though. Thanks