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RE: Partially rigid connection design

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I am not saying that good research is not a worthwhile endeavor. What I am
saying is that I believe there are three elements/phases of engineering:

1. The science of engineering-Testing, research, development of algorithms,
etc.
2. The art of engineering-Extrapolating the testing, research, etc. to "real
world" problems
3. The business of engineering-The act of performing the above within
contractual budgets and schedules.

It would be irresponsible to be spending time on one element while being
paid to do another. IMO, a lot of code documents appear that they were
prepared ignoring the consequences of item 3.

Regards,
Bill Allen

-----Original Message-----
From: T. Eric Gillham [mailto:gk2(--nospam--at)kuentos.guam.net]
Sent: Thursday, June 18, 1998 4:48 PM
To: seaoc list
Subject: Fw: Partially rigid connection design



I whole heartedly agree with Majid.  Those PhD issues form the bases for
our real world solutions.  I feel that it is a healthy curiousity and
desire know the underlying reasons for things that separates a technician
from an engineer.

T. Eric Gillham PE
----------
> From: Majid Sarraf <msarraf(--nospam--at)uottawa.ca>
> To: seaoc(--nospam--at)seaoc.org
> Subject: Re: Partially rigid connection design
> Date: Friday, June 19, 1998 1:10 AM
>
> >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.
>
> In my humble opinion,
> Performance of steel connections is real world problem. I refer you to
SAC
> reports on performance of steel connections (modeled and designed for
years
> by engineers as unbeatable rigid connections!) during Northridge
Earthquke.
>
> I do not deny that
> some Ph.D thesis are far from practice, but many are not. In fact if it
was
> not because of many Ph.D and Master's thesis project conducted in the
past,
> there would be basically no sound and proven equations and provisions in
> design codes
> to be used by engineers now!
>
> Lets us help one another to find practical solutions to engineering
> problems, not by ignoring them and not by blaming each other for wasting
> time to find solutions. Timely and sound solutions are needed whether
found
> in design offices ,or in universities. I personally do appreciate design
> engineers who try to understand and use the code, rather than applying
the
> code blindly to finish up a job fast. Sound design should never be
> sacrificed for saving time.
>
>
> To determine degree of rigidity of connections and analysis of simple 2-D
frames
> refer to the book By W.F. Chen on Stability of Semi-rigid Steel frames.
It
> comes with a program to determine the rigidity and another program to
> analyze 2-D frames with semi-rigid joints.
>
>
> Regards,
>
> Majid Sarraf
>
>
>
>
>
> >
> >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
> >> >
> >>
> >
> >
> >
> >
> >
> >
>
>
>