[TowerTalk] Steel vs. Phillystran guys...tower failure modes!

[StellarCAT]

in addition... while thinking about the conclusion of K7NV's tower stress analysis I wondered 
why I have never heard of a tower failing due to the BASE rupture or anything related to the base! 
If indeed the worse case stress is at the base with the lowest safety factor typically being caused 
by bending then why are there no failures at this point?! [Or are there and I have just not heard of them?] 

All the tower failures I have heard of were due to twisting and not related to the base failing. Thus is it 
indeed possible, although the math says it is the weakest link, that the base has a higher safety factor 
(i.e. something was left out of the calculation - not an unusual circumstance and by no means a 
derogatory comment on K7NV's excellent analysis)? 

Has anyone heard of a tower failing AT THE BASE (when installed properly of course)? 

Also - does anyone have the RTS rotating tower system rotor and can you say if there is any "pivot" 
capability due to the rotor section? If it allows pivoting of even 1/2 degree this would I believe be the 
equivalent of a tapered point base section would it not?

Gary 
K9RX