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RE: Need "Flitch-plate" design example

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I mainly do heavy industrial design so I don't have applications for
flitch plate design often, but I do have several supporting my house.
If I recall correctly that are built with 1/4" plates between 2X10's
spanning about 16' and each one supports about 10 feet of tributary
floor width, a wall with several door openings, and then a corresponding
ceiling and roof load.  No problem with wall cracks or deflections. The
assemblies are held together with about 1/2" diameter bolts on about 4'
centers.  On the few occasions when I've designed flitch plate beams I
recall the numbers working nicely.

Ed Marshall, PE
Simons Engineering

> -----Original Message-----
> From:	Bill Allen, S.E. [SMTP:billallen(--nospam--at)]
> Sent:	Thursday, May 14, 1998 5:32 PM
> To:	seaoc(--nospam--at)
> Subject:	RE: Need "Flitch-plate" design example
> When you say that this method "works", do you mean that you can
> produce
> calculations that are satisfactory or that the built-up section
> actually
> performs the way you intended it to (i.e., stresses are adequately
> transferred to the steel plate). My concern would be that, since the
> bolts
> are in wood and will deform), no (or little) load will actually
> transfer to
> the steel plates. In my mind, this is nothing like "composite" action
> since
> the deformations of the two materials are so incompatible. If you were
> talking about welding a flange plate on a steel girder, that would be
> different.
> Obviously, I have no "warm fuzzies" about strengthing a wood beam with
> a
> steel plate.
> Regards,
> Bill Allen
> -----Original Message-----
> From: T [mailto:vicpeng(--nospam--at)]
> Sent: Thursday, May 14, 1998 2:09 PM
> To: seaoc
> Subject: Fw: Need "Flitch-plate" design example
> Dennis
> I have done this many times.
> Points to heed
> 1)    If plate is not within the timber plies, i.e. laterally
> restrained,
> you have to calculate the bolt spaces by investigating the potential
> for
> plate buckling.
> 2)    If the plate is laterally supported such as with the bottom/top
> flange
> like with an angle then with good bolting patterns the section
> properties
> can be calculated with tranformed sections methods.
> 3)    You may need t consider torsion of the transformed section
> depending
> on your load application.
> Otherwise no different from ordinary beam design.  I have used this
> for many
> instances where header depth is restricted and a full steel section is
> not
> wanted.  Works like a hot damn!
> Thor Tandy  P.Eng
> Victoria  BC
> Subject: Need "Flitch-plate" design example
> >My client does not want to remove and replace an existing 4x16 DF #1
> Beam
> only on.........
> > side and is to be lagged to the face of the existing
> beam.
> >
> >If anyone has a sample of an analysis that I can follow, I'd
> appreciate it.
> >
> >Thanks
> >Dennis Wish PE
> >
> >
> >Dennis S. Wish PE