RAFTER POINT LOAD

IF A RAFTER SITS ON 2X6 PLATE, 3/4" PLYWOOD SUBFLOOR,
11 7/8" OR 14"TJI(SPAN VARIES).THE DISTANCE FROM RAFTER
POINT MEETS 2x6 PLATE TO INSIDE FACE OF 2x6 @16"OC EXTERIOR
WALL IS 8". CAN THE ROOF LOAD ON EACH TJI NOT BE TAKEN INTO
ACCOUNT AS A POINT LOAD, SINCE THE DISTANCE IS LESS THAN THE MEMBER DEPTH?
ALSO BLOCKING IS PROVIDED UNDER THE 2x6 PLATE PERPENDICULAR
TO TJI.

 

[LPPE]

Where does the load go, then?

 

TJI FL JOISTS WOULD TRANSFER THE 8" DISTANCE LOAD TO EXTERIOR BEARING WALL

 

[LPPE]

Let me see if I follw you - You have TJI rafters that bear on a 2x6 plate. This plate is on top of 3/4" plywood on top of 11 7/8 (or whichever) TJI joists, but the rafter comes in mid way between TJI floor joists. The TJI joists then bear on a 2x6 top plate over the 2x6 studs in the wall? If this is the case, I would check your 2x6 rafter plate on the flat. If that's OK, then the load should go to the wall studs. Also, is there an LVL rimboard? That should transfer the loads directly to the wall studs.

 

THE RAFTER IS 2x10 OR 2x12 NOT SIZED AT THIS TIME.
THEN THE RAFTER SITS ON A 2X6 plate, the inside end of the rafter to the inside face of exterior wall is about 8" do to the design of the eave (not at mid point of tji),which sits on 3/4" plywood sub floor, which sits over tji floor joists,(there are no tji rafters),then each tji floor joist would transfer the load to the exterior wall.and yes ther is a lvl rim board

 

[JAE]

GUSET

If I understand the geometry, then the rafter load path goes through the 2x6 plate, through the subfloor and then into the TJI at its end, almost directly over a load bearing stud wall below.

If this is the case, then the TJI really won't feel any significant increase in shear or moment as the load is directly over the support below.

However, you do need to check web buckling in the TJI. APA design guidelines indicate that any end reaction greater than 1500 lbs. requires end stiffeners as well as cases where there is a top flange load applied which is greater than 1000 lbs. Other Plywood Web manufacturers have tables that indicate when web stiffeners are required.

Also remember that your total web load at the support includes both the rafter reaction as well as the TJI reaction.

 

[LPPE]

I follow you now. Your rafters come down on the TJI's 8" off of the studwall, not directly over the studwall. Do what JAE said, check the shear. Also, if your rafters come down short of the stud wall, won't you have to cut the TJI floor joist at an angle so the top corner of the joist is not poking out of your roof?