Non linear FEM analysis οf composite concrete slab exposed τo extreme thermal load

Numerical approach using the FEM has been used to model the behavior of a composite concrete−steel structure exposed to fire. Geometry of the structure is considered as a simply supported beam, which supports the slab. Fire load has been defined by a nominal standard ISO 834 fire curve. Fire resistant gypsum board protection of the structure is considered during the thermal analysis. Both, thermal and structural response are obtained using a FEM software ANSYS. Temperature-dependent nonlinear thermal and mechanical properties of concrete, reinforcement and steel are adopted in accordance with Eurocode standards. Nonlinear material model Menetrey-Willam with compression hardening and softening and tension softening features has been used to describe the behavior of concrete elements.