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Re: Need advise on adding tension rod to wood beam to control deflection

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I too have had good success with this approach.  
Remember, when the center post is removed, you'll be increasing the moment by a
factor of 4, the shear by a factor of 2 and the deflection by a factor of 16. 
You're going to have to add a LOT of stiffness to the existing beam, and I think
that when you crank the numbers, you'll find that the contractor's suggestion to
add a tension rod won't work - and the flitch plate scheme will be difficult (if
not impossible) to install.

Good Luck,
Lew Midlam, PE
==========================

Geiger Engineers wrote:
> 
> >A client built a custom home about ten years ago. He installed a 6x14" DF#1
> >beam through the livingroom to span 27 feet. The beam was supported at each
> >end and with a column in the center - 13'-6" each clear span.
> >A new homeowner wants to remove the center column. The original builder is
> >on the scene and wants to consider an alternative to replacing the beam or
> >adding a beam below the existing.
> >He suggested the installation of a tension rod at the bottom of the beam to
> >pull the beam up level. I've done similar in truss repairs, but don't feel
> >comfortable with this since it would either rely up lag bolt connections at
> >the angled plates on each end or require the contractor to plate the top and
> >bottom of the beam and drill through the 14" member. The top is probably
> >already solid blocked which would make the installation of the top plate
> >difficult.
> >Any suggestions.
> >Has anyone tried using 1/4" steel plates on both faces of the beam and
> >stitching through with machine bolts (similar to a flitch plate design)?
> >I could use some advise on this one.
> >Dennis Wish PE
> >
> Dennis:
> I have run into this situation several times and had good success using
> full span steel channels bolted along each side of the timber member.  The
> end detail for the channel is set up such that full bearing is provided on
> the top of the timber member, and it can be tightened to preload the steel
> member.  If you are interested I can e-mail you the detail directly.  The
> above assumes that the timber member is situated below the joists rather
> than having the joists framing into hangers on the face of the timber.
> Selection of the steel channels is based on relative stiffness of the
> composite beam, and distribution of forces to the steel and timber as
> appropriate.
> Best Wishes.
> Craig Funston S.E.
> Geiger Engineers
>