Monopole Collapse
Monopole Collapse
(OP)
I work primarily in the communications structures arena designing monopole structures. Requests from jurisdictions have begun to come in for fall zones and fall zone requirements. A focal point "buzz" phrase has emerged requesting or requiring "self-collapsing" monopoles.
Poles generally fail at base welds, bolt/foundation failure or simply by buckling at critical sections. I have been on testing programs where we performed full scale failure testing of poles and we never dropped one to the ground...it is virtually impossible to produce enough sustained load (without winches or a dozer) to plastically deform a pole to the point of dropping it.
Does anyone here have any thoughts or experience on this? I can understand designing poles to have fusible points but it takes really small sections that are atypical or not available to force failure at a defined location to identify a fall zone or cause self collapse.
I know letters are written kind of explaining away this issue for the jurisdictions but, as one guy told me, he just writes a letter stating the pole will fail in a self contained mode and will not fall outside a legnth of the top pole section.
THanks in advance for any input.
Poles generally fail at base welds, bolt/foundation failure or simply by buckling at critical sections. I have been on testing programs where we performed full scale failure testing of poles and we never dropped one to the ground...it is virtually impossible to produce enough sustained load (without winches or a dozer) to plastically deform a pole to the point of dropping it.
Does anyone here have any thoughts or experience on this? I can understand designing poles to have fusible points but it takes really small sections that are atypical or not available to force failure at a defined location to identify a fall zone or cause self collapse.
I know letters are written kind of explaining away this issue for the jurisdictions but, as one guy told me, he just writes a letter stating the pole will fail in a self contained mode and will not fall outside a legnth of the top pole section.
THanks in advance for any input.






RE: Monopole Collapse
For guyed structures we could design break points and cause them to "drop down" within a reasonable radius. That's achievable with guyed structures, but not necessarily so with monopoles. I don't like designing failure points into any structure...it's just not in our nature to design for pre-determined failure...although our designs will fail if subjected to overload...that's just the nature of efficient design.
RE: Monopole Collapse
If the overall height is 9 units and the lower section is 4 units, collapse could be contained within a radius of 3 units, or 1/3 of the original height.
BA
RE: Monopole Collapse
This seems silly... be a shame to prevent construction within 300' of a 30 storey building... or similar construction...
Dik
RE: Monopole Collapse
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Mike Halloran
Pembroke Pines, FL, USA
RE: Monopole Collapse
RE: Monopole Collapse
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Where are the standards?
RE: Monopole Collapse
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RE: Monopole Collapse
Thanks again for your input. As I learn more I will post here just to educate us all.