NUMERICAL ANALYSIS OF PARTIALLY ENCASED STEEL AND CONCRETE COMPOSITE BEAMS IN FIRE USING THE FINITE ELEMENT METHOD

Resumo

It is known that unprotected steel elements perform poorly when exposed to high
temperatures. However, when the concrete is associated with steel elements, there is a gain in both the
structural and thermal aspects. Thus, in this paper, the numerical results of the thermal elevation -
obtained by the finite element method - are compared with the experimental resu
for partially encased composite beams in a fire. For this, a transient analysis was used to
determine the thermal gradient in the studied sections in order to obtain results closer to those
observed in the reference tests. The numerical results showed good approximation, accurately
representing the experimental model. From that point on, new analysis were carried out in order to
compare the numerical results with those obtained by national normative codes. It was verified that the
normative methods are not able to predict with precision the elevation of temperature in partially
encased steel and concrete composite sections, being necessary to use alternative methods found in the
literature.