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Re: pole structure connections

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Reminds me of a problem with some utility poles.  They were welded up and then hot-pipped galvanized which, I think caused hydrogen embrittlement.  They vibrated in the wind and some actually fractured and fell to the ground.

I guess I'm saying to oversize the welds if you galvanize.

MJ

--- On Mon, 6/28/10, Tom.Hunt(--nospam--at)fluor.com <Tom.Hunt(--nospam--at)fluor.com> wrote:

From: Tom.Hunt(--nospam--at)fluor.com <Tom.Hunt(--nospam--at)fluor.com>
Subject: Re: pole structure connections
To: seaint(--nospam--at)seaint.org
Date: Monday, June 28, 2010, 1:40 PM


Paul,

Unless you are in a terrifically windy area or  your structure is subject to significant vortex shedding issues you normally do not have to design for fatigue.  However, this is a case where some prudent engineering judgement might be necessary.  Who knows if you might get a couple of bored teenagers pushing and shoving on your structure.  You may want to show a full depth PJP weld which is close to a full pen weld without the backing or perhaps some very generous fillet welds.  Quality control is probably your biggest concern.  If I remember right, this same issue came up a few years ago with a lot of damaged light poles which I believe had some bad welds.

Thomas Hunt, S.E.
Fluor




PFFEI(--nospam--at)aol.com
06/28/2010 01:06 PM
Please respond to seaint
To
seaint(--nospam--at)seaint.org
cc

Subject
pole structure connections







I am working on  a project that includes a canopy shade structure supported by a single pole.  The pole is welded to a base plate that is anchored to a concrete footing.  (not possible to embed pole in concrete).  The pole has architectural limits on size, but at that dimension, I have double capacity when subjected to a 1g lateral load and am also within code displacement limits (0.02)h (sx).  
 
However, the pole oscillates when pushed on.  Do I need to be concerned with fatigue at the joint of the pole to the plate?  Should I spec a special electrode for that joint?  The model is similar to the pole structures that support light in parking lots or street intersections - is anything special done in those instances for welding and material space?
 
Thank you,
 
Paul Franceschi, S.E.
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