Is this a TJI joist failure?
Dave Miller
be failing. I'd appreciate any opinions or informed comments. The
problem is best explained with theses pictures linked below.
Picture 1 http://photos.yahoo.com/bc/davemiller11us/vwp2?.tok=bcMGYTPBxRzcFJl.&.dir=/TJI&.dnm=Picture+1.jpg
View to the west. Note crumbled flange at the lower right. Note gap
above the squash block on the left.
Picture 2 http://photos.yahoo.com/bc/davemiller11us/vwp2?.tok=bcMGYTPB869zjHQp&.dir=/TJI&.dnm=Picture+2.jpg
View to the east. This is the same joist flange as in the lower right
corner of the picture above. Note the cracks along the flange surface
that extends from the flange end seen in picture 1. Also note the
crack in the end of the joist next to it.
These are TJI 250 11-1/2 inch joists, 16 in OC, and they span 17 feet
to both the east and west of the supporting Microllam beam shown. The
pictures are typical of many of the TJIs on this beam. There is no
wall above this location. The joists running west support only the
open floor of the family room. The joists running east support a
supporting wall 4 feet to east and parallel to the Microllam beam.
The 3/4 inch T&G plywood subfloor floor dips about 1/4" just west of
the Microllam beam. Hardwood flooring will be placed over the
subfloor.
Are the TJIs properly installed? Is this a TJI joist failure? Should
I be concerned?
TIA!
harriswest
With the caveat that I'm no expert, I'd be concerned if it were my
house. TJI beams need to maintain their integrity to maintain their
strength. It looks as though you got some settling or shrinkage which
cracked the ends.
It may be possible to sister that beam about two feet out on either side
of the existing one and brace up the joists, but you should really show
an engineer this problem. It's fixable, but you need some professional
advice.
--
Mike Harris
Austin, TX
mailto:harri...@swbglobal.net
Founder, TNWPS (Texas Nuclear Weapons Preservation Society)
mailto:TNWPS-s...@yahoogroups.com
James Buttonow
Call the local building inspector and ask him to look the job over.
Also get a rep from the place of purchase to examine for proper installation.
www.wolman.org
Matthew S. Whiting
I'm not an expert with TJIs, but this does look suspicious to me. Is
this under a load bearing wall, perhaps? It appears that either the
beams were damaged prior to installation, or are under extreme stress
now. I'd definitely have someone take a look at it. A structural
engineer would be my first choice (I'm an engineer so I may be a little
biased), second a good building inspector and third a rep from a local
building company that sells TJI beams.
Matt
Bob Morrison
> The TJI 250 joists in my home presently under construction appear to
> be failing. I'd appreciate any opinions or informed comments. The
> problem is best explained with theses pictures linked below.
Dave:
The split in the bottom flange could have been caused by a "rollover" of
the top chord when the joists were installed. I noticed there is no
blocking over the support at the particular joists and at the adjacent
ones as well. The flange splits will also happen if the nails are too
close to the end of the joist.
You will note that the nail through the bottom flange is bent. I would
guess there is a second nail at the same location. If 2 nails, then the
flange would definitely split.
One scenario: the contractor rolled over the joists which pulled out
and bent the flange nails. Instead of lifting the joist and pulling the
nails, he just jammed it back down added a second nail which split the
flange.
For repair I recommend that you add web stiffeners at the supports and
that you add blocking between the joists over the support at all
locations. This is especially important if you are in a high seismic or
wind zone.
All of the photos show poor installation technique. Most (if not all)
of the I-joist manufacturers recommend solid blocking between joists at
bearing points in order to prevent the type of failure shown.
--
Bob Morrison
R L Morrison Engineering Co
Structural and Civil Engineering
Poulsbo WA