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Re: Curved Steel Frame

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Ed,

Why not use segmental construction where all the beams are straight elements
between columns? Are all the structure elements to be exposed to view?  The edge
of the curved deck and wall can be supported with outrigger channels or beams
which cantilever out from the straight beams. The cost of curving all the
perimeter beams could be saved and then the lateral forces could be dealt with in
a straight forward manner.

Jim Kestner, P.E.
Green Bay, Wi.






Roger Turk wrote:

> Ed,
>
> Speaking only of curved structures subjected to lateral loads in general, the
> structure will behave more as a shell than it will behave as a conventionally
> framed structure.  A curved retaining wall will not behave as a cantilever
> until it cracks due to circumferential stresses.  Similarly, a curved
> building subject to lateral forces acting *towards* its concave side will
> subject the horizontal circumferential beams to tension and lateral forces
> acting *towards* the convex side will subject those same beams to
> compression.  The radial "frames" will not behave as frames until the
> horizontal circumferential beams (or their connections) fail.
>
> A. Roger Turk, P.E.(Structural)
> Tucson, Arizona
>
> . > Ed Gonzalez wrote:
> . >
> . > Greetings:
> . >
> . > Can anyone share their general thoughs or comments, for the design of a
> . > two story, three-bay CURVED ordinary steel frame for lateral seismic
> . > loads in a Zone 4 region.  SAC 95-01, FEMA 267 and FEMA 267a. will be
> . > adhered to as much as possible.  The columns are not equally spaced.
> . >
> . > We plan to orient the columns with the strong axis along the curve, and
> . > have the beams fabricated so as to follow the curve contour as much as
> . > possible. The max. eccentricities are 18", 10" and  6".  Shear studs will
> . > be placed along the top beam flange.
> . >
> . > Of particular concern is the best way to model the frame while accounting
> . > for the potential torsional demand on the beams and connections. Modeling
> . > of the deck is being considered. We want to start using an elastic
> . > program (RISA3D) and then gravitate into using an inelastic software as
> . > deemed needed.
> . >
> . >
> . > Regards,
> . > ed gonzalez
> . >
>



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