A325 bolts in lieu of A394

[iouone2]

Specs says we have to use A394 bolts for transmission towers.
But we want to propose to use A325 instead. Will there be any effects on the tower if we use A325 instead of A394 bolts?

thanks in advance.

 

[bradleyelwood]

I have built a lot of power transmission towers over the years. For the rest of the engineers reading this, most power transmission towers are tested to failure. It is very interesting to watch a big tower react to simulated wind and ice loading in a full scale test facility, even more interesting to second guess where and how it will fail. Most interesting when they fail catastropically (they dont usually come crashing down).

Look up the mode of testing failures in the history of the tower types before you go changing bolts.

By the way, do you know that a lot of towers test between 1.01 and 1.15 times the full design load and fail?

 

[oldrunner]

How big are your bolts? I believe you can only buy A325's up to 1.50" diameter while the A354's, we can obtain 4" diameter. Also I believe that A354's are about 10% stronger that A325's.

 

[bradleyelwood]

90 per cent of the power transmission towers in the US use 5/8 bolts. About 8 percent use 3/4". A few towers use 7/8" bolts.

A few tubular poles use sloppy connections with oversize holes, such as 1 1/2" studs in 1 3/4" holes where the fastener does not really clamp the pieces together. (The concept is to confuse the linearity of the frequency responce to destruction by VonKarman vortices.)

Iouone2, are you looking at the thread you have started? Do you have the information you requested? If you need to talk to some people in the design end of things, let me know.