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Re: Partially rigid connection design

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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
>