Amateur timber framer; 10x10 kingpost; timber grade.

[Leo A]

Mi 1st: this site is amazing- I'm extremely thankful for this resource and grateful to be here.

I had a loblolly poine cut down in my back yard and a sawyer come mill it out as per the the lumber list I got from my shed plans. The butt log had too many metal detector hits to get milled and what I was left is some lower quality timber.

After reading great responses to a 2017 post about knots, I'm questioning the integrity of a lot of my timber and will be replacing at least 25%.

However I'm still skeptical about dumping some of this stuff. Given what I imagine to be the actual stress going on these timbers and their size I still want to use the timber below as a tie beam. 

Is there a way to mitigate this structural deficiency? Ie sistering it up?

How likely is it to split?

Given this is just a shed, what am I risking, the frame lasting only 10 vs 30-40 years? 
These are pics of the plan and all 4 sides of the center of the potential tie beam
 

 

 

 

    

These are pics just off center of the piece I plan to use for the tie beam. 

[Don P]

Good morning Leo. I asked the admins to move your post over to this forum, it was in the "for sale" section. It should fit in here a little better and be seen by more framers.

Your tie... It's hard from pics but I think it would be optimistic to call it #3 material. I try very hard to step outside of my immediate need when grading. I would break that down into brace stock if possible, removing that section. If you look at the slope of grain around most of that gnarly, bark included knot, there is only one face showing a strap of some continuous, strong grain. How much good wood is there I can't really tell, dubious.

You mention sistering, that would be a good option. Background; We had a post a month or two ago showing precisely this truss design. It is a very poor way of constructing this truss. By raising the tie the tension forces in the tie increase. Follow the tie out to the connection of tie to top, rafter, chord. 3 pegs on the tension side of the neutral axis of the top chord, that is a forbidden connection for good reason. Tension perpendicular to grain is one of the weakest ways to tie wood, we don't even have published design values for most species in this direction. (In that previous discussion someone inferred that a noted engineer had designed this truss, that engineer has lectured against using this connection accompanied by pictures of failures, so I'm skeptical of that).

I do like that this design provides an overhang. If you sister a 2x on each face of the tie full length, extending across the top chord, make the connection on the far, compression, side of the top chord, now you've solved both problems. The low grade tie is simply a filler, the fish plates are the strap and are well connected on the far side of the neutral axis of the top chord. Watch your end distances on the connections through the fish plates.