19 Dec 09 22:53
I imagine that it's a bit late to provide any useful information on this project in view of the fact that the thread was started back in August.
Still, I would offer the following just for the record:
I have designed many pole structures as well as having analyzed some lattice towers. Quite often a municipality might require an engineer to provide a "fall zone letter" to certify that a pole structure will not collapse beyond a certain radius (especially with telecommunications poles).
This is easy to do if you are the one specifying the pole strength, since you can design a pole's slip joint connection that would just meet the code but, overloaded beyond that, would collapse outside the fall zone. Then you size all the parts below it to have a higher overload factor than does the joint.
A lattice tower is an entirely different story. You would have to either obtain a backup file of the pole model (hopefully done with PLS Tower), or would have to get the shop drawings and create the model from scratch (and trust me, you don't want to do this unless you have nothing else to do for many, many days). Then, you would run the model using the worst load case provided by the utility company and see where the weakest members are.
If you're lucky, you might be able to beef up members and joints in the lower part of the tower so that the upper part of the tower that would lie outside the zone would have to collapse first. In any case, it would be mammoth job, and depending on how the tower was made, you simply might not be able to accomplish the objective.
Barring that, you could replace the lattice tower with a slip joint monopole and design it as described above.
In short, there is no easy out. As TransmissonTowers has said, it is surprising that HUD was not more concerned about the EMF than having the tower collapse.