----- Original Message -----
Sent: Friday, September 07, 2007 11:36
Subject: RE: Bent Beam/Frame
If the tube steel members are connected together with a full pen weld
at the apex, you have a "fixed" condition at
the peak and your FBD should not show any lateral reactions unless there
is an external lateral force. Assuming you are not using the bent
beam/frame to support any lateral forces, I don't see any problem with design
the supports for the vertical reaction only.
would want to consider the horizontal deflection of the frame though and
take that into account when designing the support
If you had a "pinned" condition at the
apex you would have lateral forces do the the ridge beam reaction that would
need to be resolved.
Josh Comfort, P.E. -----Original Message-----
Golden, Graper & Burton, Inc.
1500 W. Fourth Ave., Suite 509
Spokane, WA 99204
(509)624-3224 (509)624-3225 Fax
Sent: Friday, September 07, 2007
Subject: RE: Bent
No, you cannot just ignore the horizontal reactions
from the rigid frame. Greater rigidity may reduce the force but it
does not eliminate it. You should analyze the horizontal reactions
based on frame analysis for the stiffnesses provided, and follow the load
path and design for it.
CH2M HILL /
We are providing a steel bent beam/frame in a custom home to support
the ridge beam within the ceiling instead of the typical king
post to ceiling beam. The Steel frame is sized to
fit within the depth of the R.R. and it is a 3/12 pitch, made
with 2 square steel sections and a full penetration weld connection is
provided at the apex, where the 2 beams meet. The bearing of the frame is at
a 4x post at each end, hidden within the wall.
Now my question is, if you determine the reactions using a simple FBD
there will be an x & y reaction at the bearing points at the 4x posts,
but if the steel frame is designed as stiff as possible to limit the
deflection to negligable amounts then I am assuming that there will only be
vertical reactions in the y direction. Therefore a wood post can be used
without designing the connection for a very large reaction in the horizontal
Am I right in this assumption?