الخلاصة:
With the development of cutting and welding electric technology in steel construction, steel castellated
beams became available for manufacturers. These beams alone steel or composite steel-concrete are
commonly used in construction of large spans, such as car parks, industrial buildings and sometimes
used in art works, grace to their economic and aesthetic benefits.
The calculation and verification of castellated beams with only steel, instability phenomenon at lateral
buckling according to the European code EC-3 is similar to that of solid web beams, replacing the
geometric characteristics of the full section with those in section perforated. This analytical solution
neglects the instability caused by buckling or shear web-post on the full resistance of the beam, this code
only gives construction details for the design and verification of such beams. For composite castellated
beams, we note that the EC-4 code provides no method or constructive device on the calculation and
verification of this type of structure, which leaves much space for research and development.
In composite beams with solid web, Eurocode 4 allows linear elastic global analysis where the
composite section is considered homogeny (interaction is complete) and the behavior of materials is
considered linear elastic. In the case where the connection is partial, its effect is introduced into the
calculation by two factors; an amplifier factor which depends on the profile deformation and the
composite section in full connection deflection, and the other reducer factor depends on the resistant of
the profile and the composite section in total connection.
In this work, we developed numerical models in 3-D finite element capable of analyzing the instability
of steel castellated beams with slender web-post at lateral buckling on the one hand, and non-linear
analysis mixed perforated beams other hand. The non-linear behavior of the different component beam
(steel, concrete and connection) is fed into the numerical calculation using the ANSYS code.
The selected three-dimensional models are validated by comparison with existing results in the
literature. They are efficient to represent the influence of the geometry of the web-post on the instability
of castellated beams the lateral buckling phenomenon for non-composite beams, and to represent the
influence of the degree of connection on the sags and the flexural capacity perforated composite beams.
