Like Jerry, I use the pre-eng lumber or steel HSS for heavy loads. I
try to use only pre-eng lumber in exterior walls to avoid problems with
cold steel.
Gary
Jerry Coombs wrote:
> I've never used a flitch plate for axial. Don't think I would as
> getting the buckling eliminated would take a lot of bracing or an
> awfully thick plate.
> Flitch plates have pretty much gone the wayside since all the
> engineered lumber (LSL, LVL, PSL) have come on. One of these will
> likely work. If not it may be time to think about a steel tube.
> Only time I'd use a flitch plate these days is on a small site where
> an LVL would be too heavy and the flitch plate could be assembled in
> place.
> JDCoombs
>
> >>> On 10/16/2007 at 2:13 AM, "Scott Maxwell" <smaxwell@umich.edu> wrote:
> I just wanted a "sanity" check to make sure that I am thinking
> correctly...
>
> I have a rather tall post that "wants" to be wood, but must be of
> limited depth and to a lesser degree limited width. To accomplish
> that in wood, we are looking at a flitch plate. I have no problem
> designing the flitch plate/wood for bending, but there will also be an
> axial load. So, I want to make sure that my thinking is on point. I
> am thinking that the flitch plate would strictly add to the buckling
> length calculations (i.e. the Le/d) of the wood portions. But I
> cannot quite seem to see an easy way to account for that since in wood
> it is purely a brace length over depth of member calculation, not a
> L/r calculation (i.e. calculated section properties). I was thinking
> of calculating the transformed area section properties and then
> figuring out an "equivalent" depth of wood to get similar section
> properties and then using that "equivalent" depth in the Le/d
> calculation for the wood. Or should I just assume that the steel is
> really taking the axial load and do standard kL/r calculations and
> assume that the axial load gets transferred from the wood into the
> steel? In one direction, it is moot since post is embedded in a
> wall...thus the weak axis is basically fully braced...it is the out of
> plane length that is the issue.
>
> Or should I go to the Le/(r*sqrt(12)) that is indicated in H.3 of the
> 2005 NDS for "other column shapes" and use the transformed area value
> for r?
>
> I am also looking at just using a steel shape with wood nailers, but
> want to have the flitch plate option available if they REALLY push for it.
>
> Thanks,
>
> Scott
> Adrian, MI
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