It's mostly a matter of risk management. The concrete is fairly strong in
24-48 hrs, and won't reach its ultimate strength for weeks, months, or
years. Presumably, the footing was designed to take loads under moderately
extreme conditions (big antenna, howling hurricane force winds, simultaneous
earthquake, tornado, and material failure). I don't know what the ultimate
strength vs the 24hr strength might be, but I'd be real suprised if the
loads imposed during erection are even a tenth of the ultimate design loads.
Obviously, you don't want to be out raising the tower in a thunderstorm,
but, assuming you ask the folks who supply the concrete what their
recommendation is (mostly based on it being "hard" and "mostly cured"),
you're probably in pretty safe territory.
However, if you're racing to get the tower up with all your antennas on it
before the next winter storm blows in, you might want to think twice?
>At 08:49 AM 11/14/2004, firstname.lastname@example.org wrote:
> >Hello All,
> >I have a question regarding tower base concrete.
> >How long should concrete cure after pouring to
> >be safe to install a crank-up, tilt over tower???
> >The mix is 3500 psi.
> >Many Thanks in advance. 73, Ted K2QMF
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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