Originally Posted By: dedwards This post was automatically imported from our archived forum.
Joseph,
As soon as I saw this pic I thought to myself that this is not No.2 southern yellow pine (structural) but rather looks like Lodgepole pine (interior wall studs). Furthermore, the gussets at the joints appears to be way too small, narrow and wimpy. Normal gussets cover the entire width of the joints even to the point of hanging out off the edges. Like you I have never seen trusses with rounded edges but I have seen many wooden studs with them because it makes it easier for the drywallers to install the drywall. This just does not smell right. Could these be homemade trusses or someone screwed up at the truss manufacturers’.
Originally Posted By: kshepard This post was automatically imported from our archived forum.
Joe, I agree, gussets look too small and the truss members being gusseted together don’t look flush, either. This does not look right at all. Rounding over edges adds cost to the milling process and where’s the benefit?
I’d recommend confirmation of the truss specs by a qualified structural engineer or failing that, truss evaluation by the same.
Originally Posted By: ccoombs This post was automatically imported from our archived forum.
Joe
It is common to use this type of truss plate at web connections. The plates are installed smooth, so I wouldn't think this was a homemade truss or filed made truss.
As for the rounding of the ends, I'm sure there is a (money saving) reason for doing such. My guess is it makes it faster/easier to build the trusses. I would assume they order or mass cut the ends of all the web members. That way you don't have to make a custom or exact angled cut to fit the angle of the truss. You would still have to deal with the connection at the bottom chord. But it is one less "exact angle" cut.
As for lumber types, it is very typical for a different type of lumber to be used for the web of the truss. In California we use Doug Fir-Larch for our nailing connections at the roof sheathing and bottom chords for drag trusses. However, SPF is much less expensive, so they use it at the web members.
If there is a concern with a manufactured truss, I would recommend the owner contact the truss manufacture. They will typically provide customer service/fixes/etc. at no additional cost.
Originally Posted By: phinsperger This post was automatically imported from our archived forum.
Quote:
Although the maximum gap allowances in Section 3.7.6.1 have been simplified, the actual amount of gap permitted between wood members has not changed considerably from earlier criteria. The most notable change to the gap criteria in the 2002 edition is that they are now applicable to joints with single points of contact between wood members,
such as at joints with round-ended or square-ended web members. Gap criteria in the 1995 edition, and earlier, were given only for joints with members that were cut to bear on a surface, thus requiring gap allowances for round-ended webs, or other web members not cut to bear, to be stipulated by the Truss Designer for each case. In the absence of a
specified gap allowance, these webs were required to have a point of wood-to-wood contact with each adjacent member (i.e., no gaps), as indicated on the truss design drawing. The 2002 edition now permits
a maximum gap of 1/8" to occur at these points of contact. Although the Standard now addresses quality related issues for trusses manufactured with round-ended or square-ended web members when shown on the truss design drawing, the Standard does not include provisions in the design procedures for these types of members, which require some
additional design consideration. Thus, the design considerations implicit to round-ended or squareended web members must be made by the Truss
Designer based on engineering judgment or testing
Originally Posted By: jsmith10 This post was automatically imported from our archived forum.
Thanks Curtis & Paul,
GREAT link explaining the rounded trusses.
I'm sure engineers have figured everything out for cost savings and strength but I'd be afraid of truss failure with a heavy snow load. The straps tying these in are only 1 1/2" wide and approx. 4" long.
In my mind, I see a pivoting issue with heavy load to normal load conditions, and possibly weakening the web strap over a period of time.
But that's only my opinion as a craftsman.
Thanks so much for all your replies guy's. This is what makes NACHI #1 and not just for inspectors.
Originally Posted By: ccoombs This post was automatically imported from our archived forum.
Great information!
I completely understand the design being controlled by the engineer's design time vs. cost/construction savings. I calculate a lot of extra headers and beams when designing houses. Many more than my peers. But if I can save $20 on three windows per plan...400 houses per projects...I just saved $8,000! Most engineers don't care or pay attention....and that is why I can value engineer better than most.
As for the truss plates....they always seemed small to me also. But the connections have been tested. The allowable value has a huge safety factor. The design loads also have safety factors. And have you tried to remove one of these gang plates?