Sunday, September 20, 2009

Re: sloping beam at beam / column moment connection

Joe,
You are essentially correct. The issue with sloped member connections is
that equilibrium needs to be fulfilled AND the WP and idealized intersection
of forces will be offset from the physical intersection of members. You need
to be aware of local effects.

In your case, the effects at the column flange will not match the given
forces at the ideal WP. If the weld between the intersecting flanges is
adequate for the forces in the flange (flange axial and shear transfer for
2D forces), then the weld is adequate regardless of the offset issues.

Thanks for pointing out the article in MSC. Most of the 60 tips are aimed to
make the structural designer consider the cost implications of their member
selections and (boilerplate) specifications. Personally, I'm inclined toward
always designing all of my connections.

Paul
--
Paul Ransom, P.Eng.
ph 905 639-9628
fax 905 639-3866
ad026@hwcn.org

> From: "Joseph R. Grill" <jrgrill@cableone.net>

> Back in June there was an article in "Modern Steel Construction" with 60
> tips for simplifying steel moment connections. Just the fact that someone
> can come up with 60 simplifying tips tells you something about the state of
> moment connection design anymore. That aside, one of the tips warned to pay
> attention to sloping beam to beam moment connections due to the vertical
> component of the flange force.
>
>
>
> I have a project to finish if it ever comes back off the shelf (hopefully
> soon) that has quite a number of sloping beam to column moment connections.
> I know this is not the same, but it got me thinking if there is something
> that I may overlook when the time comes. The vertical component of the beam
> flange force should transfer directly into the column flange through the
> weld. Correct? If the weld checks out then all should be o.k., right? Or
> is there some consideration to a slight bending of the flange since the beam
> web is coped back a bit in the connection? Any comments would be
> appreciated.
>
>
>
> In addition, I do have some software to do the connection design, but
> unfortunately it doesn't take into account a sloping beam. Something I did
> not know until after the purchase. Are there any spreadsheets out there,
> preferably free or cheap, that is available to do the design for these
> connections?
>
>
>
> Thanks,
>
> Joe Grill


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