There will be lateral forces due to unbalanced vertical load such as snow on one side evenn if there is
no 'lateral ' load.
Even with a fully fixed connection assumption, forces from both sides have to balance or there will be trouble.
Syed A Masroor
Consulting Structural Engineer
Karachi, Pakistan
> pinned supports "will" develop lateral reactions due to vertical loads
> applied to the frame. However, in this case if the base is free
> to move
> laterally, the horizontal reactions are not developed.
>
>
> Bill Sherman
> CH2M HILL / DEN
> 720-286-2792
>
>
> ________________________________
>
> From: William.Sherman@CH2M.com [mailto:William.Sherman@CH2M.com]
> Sent: Friday, September 07, 2007 11:18 AM
> To: seaint@seaint.org
> Subject: RE: Bent Beam/Frame
>
>
> No, you cannot just ignore the horizontal reactions from the rigid
> frame. Greater rigidity may reduce the force but it does not
> eliminateit. You should analyze the horizontal reactions based on
> frame analysis
> for the stiffnesses provided, and follow the load path and design for
> it.
>
>
> Bill Sherman
> CH2M HILL / DEN
> 720-286-2792
>
>
> ________________________________
>
> From: erik gibbs [mailto:erik.gibbs@gmail.com]
> Sent: Friday, September 07, 2007 11:04 AM
> To: seaint@seaint.org
> Subject: Bent Beam/Frame
>
>
> 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,
> hiddenwithin 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 direction.
>
> Am I right in this assumption?
>
> Erik Gibbs
>