kicker brace support for cantilever wood beam

[hapunaterp]

Hello,
I am designing a kicker brace to support a exterior staircase on a house going up to a roof deck. i would like to use a PSL post in the wall from which I will extend, at a 45 degree angle, a 4x4 to the bottom/side of the header at the stringer bearing. something like a 'hangman' configuration. I want to make sure my connection from the 4x4 to the psl post is sufficient. I am proposing a 1/2" diameter thru-bolt but as I make my way through the analysis based on NDS for wood construction, I am getting caught up in the min. edge distances, min. shear area, lateral design values and fators for load at an angle to members with 2 different specific gravities, etc. Does someone have a more straightforward way of analyzing something like this? I am most concerned that the load on the 4x4 at the connection to the PSL post will fail w.r.t. tearing the 4x4. The load is about 1000 lbs. and I am not clear that the 4x4 can handle that. any suggestions would be appreciated.

 

[jayrod12]

Why not a custom steel saddle or something? That would be the way I went likely.

 

[KootK]

How about a lag screw or two perpendicular to the brace and screwed through the brace up into the PSL post? Mechanically, that feels pretty good to me.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[rb1957]

how about gusset plates (like in roofing trusses) ?

i'd've thought the deflections and stiffness were possibly more critical ?

another day in paradise, or is paradise one day closer ?

 

[KootK]

Two, more unconventional options:

1) You could notch the column to receive the brace.
2) You could fasten a length of 2X to the column for the brace to bear on.

Both of these are messy architecturally, however. Last resorts.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[XR250]

These are always messy situations. Did you check deflection in the LVL post?
I always try to do a cantilever w/o a kneebrace if it is at all possible.

 

[hapunaterp]

thank you very much for the quick input. i took the easy way out and went with a simpson knee-brace stabilizer kbs1z (2) on each end. the psl post is in the wall and sheathed so it is braced in the weak direction and the load will not be enough to cause rotation or deflection in the strong direction. one reason i was trying to go with a thru bolt or possibly a lag screw was to avoid having to cut out a piece of sheathing in order to make the connection to the brace. with a thru bolt, i could just go through the 4x4 and the sheathing and the psl post. because i was looking to use a 4x4 though, there did not seem to be enough area for sufficient edge distance to prevent the possibility of the wood tearing. i definitely err on the side of caution so i decided to go this route. i appreciate all the suggestions. i will have to use this forum more often.