NUMERICAL STUDY OF STEEL-CONCRETE COMPOSITE STRUCTURES UNDER FIRE SITUATION

Resumo

This work aims to study the behavior of steel-concrete composite structures under fire
situation. For this, numerical formulations were developed, implemented and evaluated. It is well
known that high temperature causes changes in physical properties and mechanical strength of
materials. In both steel and concrete, such characteristics deteriorate during the exposure to fire, and
the structure load capacity and stiffness are reduced significantly as a consequence of the temperature
rises. This work shows the efficiency of the CS-ASA/FA and CS-ASA/FSA FE code in the analysis of
steel-concrete composite structural elements. The first provide the temperature distribution at the
cross-section level of the elements; the second module was developed to performs the inelastic
second-order analysis of composite structures under fire using a large displacement FE co-rotational
formulation; the plastic effects are captured through the refined plastic hinge method (RPHM) coupled
to the strain compatibility method (SCM). The proposed numerical methodology success is proved by
comparison with experimental and numerical responses available in the literature, which concludes
that the developed computational tool can be used to study the composite steel-concrete cross-section
strength and advanced progressive collapse analysis of beams, columns, arches and composite frames
under fire.