> In looking through old Rohn catalog I have..... the "safe moment of
> restraint" is :
> 45g- 9610 ft lbs aprx $269.00 per 10' section
> 55g- 17,160 ft lbs aprx $319.00 per 10' section
> 65g- 33,200 ft lbs aprx $365.00 per 10' section
> Seems to me that's a huge diff, between 45 g and 55g... another huge diff,
> between 55g and 65g .
The larger "diameter" (face width) accounts for most of the increased
strength. A large thin walled tube is stronger in bending than a thinner
solid bar with the same amount of metal.
The delta price is probably proportional to the change in amount of
metal (labor to assemble is about the same: same number of welds, etc.)
(compare the weight of a section to the price)
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