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Re: Partially rigid connection design

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Probably doesn't matter at this point since you have probably busted
your company's budget and consumed all of the design fee pondering an
issue more suited for a PhD thesis than a "real world" design problem.
Once your boss tallies the hours you have spent on this project, he
probably will/should fire you.

Regards,
Bill Allen

Y. Henry Huang wrote:

> Very interesting.  How do I then, apply this concept to a "real
> structure"?
> How do I control the different degree of "connector strength"?  Or on
> the
> other hand, how do I know an existing connection is partially rigid to
> what
> degree?  Will I be required to test the connection system to verify
> this
> relative rigidity?
>
> Y. Henry Huang
>
> Public Information wrote:
>
> > > ----------
> > > From:         Christopher Wright[SMTP:chrisw(--nospam--at)skypoint.com]
> > > Reply To:     seaoc(--nospam--at)seaoc.org
> > > Sent:         Friday, June 12, 1998 8:09 PM
> > > To:   SEAOC Newsletter
> > > Subject:      Partially rigid connection design
> > >
> > > Here's a follow-up on connection design incorporating partial
> rigidity
> > >
> > > (Shouldn't be much trouble getting this approach incorporated in
> the
> > > building code. ;->) :
> > >
> > > <http://www.macsch.com/aerospace/Library/auc97/p01397.pdf>
> > >
> > > The paper shows some of the factors involved if you actually mean
> to
> > > include connection stiffness in FEA results. The fact that you can
>
> > > include a certain effect doesn't mean that you can do so
> practicably,
> > > so
> > > as to model a real situation, with some overall benefit to the
> > > project.
> > >
> > >
> > >
> > >
> > The difference between the "traditional analysis" and partial-rigid
> > analysis is on the connector. The traditional analysis assumes the
> > connector has an infinite rigidity. In most real structures, the
> > connectors are deformable. Partial-rigid analysis takes the
> connector
> > strength into considerations.
> >
> > I provide two sets of results, as below, that were extracted from
> > partial-rigid analyses.
> >
> > **Set 1: Axial Force**
> > Connector    Connector       Connector
> > Strength      Force(#)          Stiffness(#/")
> > (input)         (output)           (output)
> >
> >  100%        1929.636          infinity
> >   99%         1929.601          3.303E8
> >   95%         1929.369          6.298E7
> >   80%         1928.388          1.329E7
> >
> > This example shows the connector force and connector stiffness vary
> with
> > the connector strength. In the traditional analysis, we use only the
>
> > connector force to design the connector (and ASSUMES the connector
> has
> > an infinite rigidity).
> >
> > The procedure of partial-rigid analysis requires the connector
> strength
> > as an input, and will output the corresponding connector stiffness
> > (**connector stiffness is an output**). The design procedure
> consists of
> > two steps. The first step is similar to the traditional analysis to
> > design a connector for the connector force only. Then, we have the
> > connector dimension. And, we can determine the effective area (A),
> > effective length (L), and material constant (E). The second step
> > calculates AE/L, and checks if the connector stiffness is satisfied.
>
> >
> >
> > **Set 2: Bending Moment**
> > Connector    Connector        Connector
> > Strength      Moment(#-")     Stiffness(#")
> > (input)         (output)            (output)
> >
> >  100%        1.38E6            infinity
> >   99%         1.37E6           1.364E10
> >   95%         1.35E6           2.620E9
> >   80%         1.26E6           5.531E8
> >
> > Partial-rigid connection allows every connection strength to be
> > adjusted. This example is applied to a bending moment.
> >
> > J.Luo
> >
>