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3,2 Plastic Buckling Test of Wide Flange Section
3.2.1 Introduction
Recently "Plastic Design'' of steel structures is considered a more rational
and economical method for design. Therefore research must be done more
precisely on the plastic behavior of steel structures.
The plastic design of steel structures is based on the "simple plastic theory"
which requires the existence of the "plastic hinge". The structural members must
be designed so as not to ruduce in strength before the structure will collapse even
in the plastic range. Therefore the structure members used in the plastically
designed structure are usually wide flange section. They lose stability by the local
buckling of compressive plate elements of the sections. The compressive elements
have sufficient geometry to prevent instability by local buckling. This geometry
may be represented by the ratio of sufficient width to thickness of the plate.
Theoretical and experimental research on local buckling of plates are now in
the purpose of which is to examine
progress. The buckling test discussed here,
the behaviour of the flange and the web of wide-flange sections compr essed beyond
the elastic limit, is one of the tests of the above-mentioned project. The method
e measurement of
of measurement by ster eo-photogrammetry is applied to th
deformations of the flange and web.
Use of photogrammetric methods has the benefit of being able to easily measure
the deformation of objects three dimensionally even when the measur ement points
on the objects move due to the change of loading conditions. These characteristics
urement such as the dial-
cannot be replaced by other mechanical methods of meas
gauge instrument. Especially, in the plastic buckling test, the main problem is
the difficulty in foreseeing the places where the buckling will occur.
* . AISC-Specification *k ASCE: Commentary of Plastic Design in Steel"
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