They measure 1-3/4" (assume you meant 1-3/4 instead of 1-32/4"). They'are also used exactly how they're used in the picture on pp. 23 in the link you gave. They're buit around the stairs going into the basement.Measure the two LVL's, if 1-32/4" each, that is what they are, pp. 23: http://imgs.ebuild.com/xCat/ebuildWebB/15?ObjectID=32941&Variant=Original
If they measure 1-1/8" or 1-1/4", they may just be rim boards; http://www.ilevel.com/literature/TJ-4000.pdf (I hope not....)
I attached another picture. I found on the back side it says, "Trus Joist" and it also says "hole zone". I assume that's where it's ok to drill.Correct, I usually spell check myself, but have been sick at home today. That is my excuse and I'm sticking by it.... LOL.
Follow the guide or find the U.S. version on-line.....