Tower Crane Base Reactions

[iqls71]

I am designing a foundation for a external climbing tower crane which will have a final height under hook of 167 meters and six (6) tie-ins will be provided to main building/structure at 22.50 meters spacing.
Initially, I have designed the foundation considering its freestanding condition at a height of 47.95 meters using the supplied forces and reactions (V,M,H -Out-Service) by the crane manufacturer and considered it as the worst case scenario.
For the reason that the tower crane will stand at maximum h=167 meters, our consultant is asking for additional load case for that height. From my understanding, that load case is not critical because it will only include pure gravity loads and the overturning moment which normally contribute a higher value will be totally eliminated by the tie-ins.
I will appreciate if someone could provide me more clarification on this issue?

 

[KootK]

My understanding is the same as yours. Whatever moment will remain in the tower ought to be less than the freestanding case.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[paddingtongreen]

I agree that it is unlikely that there is a case worse than the free standing one, but I don't think it is something to be "eyeballed". When there is only one tie in place, does it reduce the moment on the foundation? if it does it must put a horizontal shear on the foundation that was not there before. I think you perform calculations to support your assumption, nothing too sophisticated, but enough to demonstrate your case.

Michael.
"Science adjusts its views based on what's observed. Faith is the denial of observation so that belief can be preserved." ~ Tim Minchin