Analysis of Slim Floor beams in fire: Emphasis on the concrete constitutive models

Resumo

The partial encasement of the steel beam in the concrete slab, in the way that it occurs on the slim floor, provides a thermal protection, improving the behavior of the beam when subjected to fire. In order to evaluate the thermal and structural behavior of the slim floor system, numerical models considering partially encased beams were created in the computational code DIANA. About the constitutive models of the materials, it wasn’t possible to represent the relations presented in the EUROCODE 4 or ABNT NBR 14323:1999, being replaced by alternative models. Numeric models were created on room and elevated temperature, contemplating all the presented options for the constitutive models of the involved materials. Parameters such as the degree of interaction between the steel and concrete and the better combination of the thermal parameters of the concrete in order to obtain a more realistic thermal response of the beam were analyzed either.