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RE: Key-Hole Base Plate

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Title: RE: Key-Hole Base Plate

>[how about] using a plasma cutter to cut out base plates and base plate anchor bolt holes in a
>continuous operation (without lifting/stopping the cutting process).  This effectively cuts the
>anchor bolt holes but also makes a 1/16" slot from the edge of the base plate to the anchor bolt hole.


I personally would not permit this. Nor have I ever seen it (but that doesn't mean it hasn't been done).

From a design standpoint, the keyhole slot in the base plate would probably not cause a problem for a gravity-loaded column that is always in compression. However, if there is any moment or uplift, I think the slot could reduce the strength and/or stiffness of the base plate. The bigger potential problem I see is the effect on erection for any column. The base plate has to hold the column up as a free-standing member. Making swiss cheese out of the thing isn't going to help keep a column vetical during erection.

I think the fabricator likes the idea of programming a continuous path of cutting into the CNC-controlled plasma cutter. However, I suggest that the fabricator instead program the perimeter cut and hole cuts separately so that they are sequential but not continuous. It's not that big a difference in CNC programming anyway.

Charlie