vertical load transfer at wood floor truss bearing 1

[BrettUW]

When using the floor truss bearing detail with a 2x band at exterior walls, how do you account for vertical load transfer. With a full-depth continuous rim the load from above is somewhat uniformly distributed to the 2-2x top plate and wall studs below. With the 2x band detail the load from above is "collected" into the ends of the trusses and is transferred onto the 2-2x top plate below as a point load. If trusses do not align with studs this can cause the 2-2x top plate to be overstressed for 2-story and larger buildings. I would appreciate hearing how some of you have handled this.

 

[MiketheEngineer]

With 2-2x4s or 2x6 top plates and studs at 16'' oc - I haven't run into a problem. But I suppose you could.

If the plates are well nailed together - you almost get a composite action - so you are looking at a section that is close to a 3.5 x 3'' deep - but maybe not quite.

Also - the chance that you will get full live load is almost impossible.

While I am not dismissing your concerns - I have have never seen this as a problem.

Good luck

 

[KBVT]

When I got to a point where a continuous double top plate could not handle the per stud point load in bending, I called for crush blocks at each stud location. Contractor wasn't a huge fan but in a 4-story building, the loads add up pretty quickly.

 

[MiketheEngineer]

Sorry - I assumed a 2 story buidling maxx. But at four stories - yes you could have a problem.

1. Go to a triple plate
2. Make sure your studs and floor trusses line up. Make sure studs are fully sheathed.
3. Drop spacing to 12'' oc if necessary

 

[BrettUW]

I ended up requiring that the Contractor align a stud below each truss and requiring that the truss manufacturer/designer design the ends of the trusses to transfer this accumulation of load through the ends of their truss since this is the only vertical load path. There were a couple locations even at two stories where I couldn't get the top plates to work (long spans, floor and roof trusses both at 24" on center). Thanks for the replies ... I was just curious to see how others were handling this.