Advanced numerical analysis of shallow and deep steel arches under fire condition

Resumo

The arches are structures used to overcome large spans, since their curvature can guarantee strength
gains. However, such systems exhibit strongly nonlinear behavior, and therefore, for a more realistic modeling, it
is necessary that numerical formulations consider several sources of nonlinearity, such as geometric and material.
In a fire situation, the analysis is usually more complex, since the materials physical and mechanical properties are
significantly affected by temperature. Therefore, this work aims to study the thermal-mechanical behavior of
shallow and deep steel arches under high temperatures using the CS-ASA/FSA module (Computational System
for Advanced Structural Analysis/Fire Structural Analysis). Basically, the analysis will be developed in two-level
approaches: the first refers to the temperature field calculation in any cross-section, where, as consequence of fire
exposition, the materials properties degradation are obtained; the second stage is intended to carry out an inelastic
second order analysis (ISOA) of shallow and deep steel arch in a fire situation. A co-rotational finite element
formulation is used to follow the large displacements and rotations of the structural model, and the material
inelastic behavior is simulated with the Refined Plastic Hinge Method (RPHM) and Strain Compatibility Method
(SCM) coupling. The numerical thermal-structural results obtained here will be validated by comparison with
responses available in the literature.