Recent proposed rafter slenderness limits, to prevent snap-through
of plastically designed pitched-roof portal frames, incorporate
the elastic snap-through buckling load of such frames. It has been
suggested that the elastic snap-through buckling load used in the
proposals is over-estimated making these slenderness limits
unconservative. This is supported by a more rigorous elastic
analysis. To test the proposals, model frames lying on or close to
the slenderness limits were tested to failure in the laboratory.
Frame dimensions were chosen so that the frames were only
susceptible to snap-through instability. Failure loads far lower
than the expected plastic collapse loads were measured, showing
that the elastic snap-through buckling load is over -estimated .
Since plastic analysis is easily applied to portal frames, these
slenderness limits are best replaced by a similar limit incorporating
a more accurate elastic snap-through buckling load. A new
limit is outlined which must still be tested by further research
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/16467 |
| Date | 12 January 2015 |
| Creators | Bryant, John Spencer |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf, application/pdf, application/pdf, application/pdf |
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