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Re: CMU

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Mark -

Thanks for your response.  A couple of more thoughts if I may.  (As you can
tell I've spent some time thinking about this issue.)

<<The out-of-plane connection we have successfully used to TJI's is a pair of
holdowns each side of the TJI web which has been reinforced with a solid web
stiffener each side of the web.  The web stiffener is usually flush to the
outside edge of the top and bottom chords.  The stiffener is attached with
glue (APA approved glue or glue used by joist manufacturer) and screwed
through the TJI web into the stiffener on the opposite side.  The screws from
both sides provide a clamping force to provide better bonding between the web
and web stiffeners.>>

Does TrusJoist mind that you are taking your shear force through the glued
connection between the web and the top flange of their joist?  Does it create
any reduction in the vertical load capacity of the joist?  Have you used this
in LA?

<<When the joist is parallel to the wall, we use a tie rod threaded through a
hole in the TJI webs (reinforced with web stiffeners) with 2x blocking tight
against each side of the tie rod .  The blocking is nailed to the plywood
sheathing using 10d at 4"o.c and attached to the web siffeners with A35's.
 At the end of the tie rod we have a bearing plate which bears on a web
stiffener attached to the web of the TJI and is big enough to overlap the 2x
blocking each side of the tie rod on the opposite side of the joist.  The
wall connection is a threaded anchor bolt and coupler to the tie rod   As the
wall tries to pull away the tie rod goes into tension, putting bearing on the
blocking which is then transferred shear through nailing to the diaphragm.>>

Do you worry about shrinkage in the 2x blocking not providing a tight fit
over time?  Do you worry about loading this connection in compression when
the wall pushes on the roof since this is really a "tension only" connection?
 Would such a load cause the blocks to fall out or separate slightly perhaps
creating an impact load in the tension rod when the load reverses, similar to
what happens in typical rod X-bracing?  Assuming that the tie rod is at the
center of the TJI's, do you worry that the eccentricity between the tie rods
and the diaphragm will cause the joists to "roll"?  

Lastly, in this parallel condition, do you use a similar type of tie rod
detail completely across the building to satisfy the 24' maximum crosstie
spacing requirement, or do you have beams in those locations?

Thanks again for all your input.

Bruce Resnick