Modeling the response of composite beam–slab assemblies exposed to fire: Fid-Bau Portal

Modeling the response of composite beam–slab assemblies exposed to fire

Kodur, V.K.R. / Naser, M. / Pakala, P. / Varma, A.

Abstract This paper presents the development of a three-dimensional nonlinear finite element model for evaluating the response of composite beam–slab assemblies subjected to a combination of gravity and fire loading. The behavior of typical beam–slab assemblies with different shear connection types (welded–bolted shear tab and all-bolted double-angle connection), exposed to different fire scenarios, was modeled using ANSYS. The finite element model accounts for temperature dependent thermal and mechanical properties of constituent materials, connections, and composite action. Transient time domain coupled thermal-stress analysis is performed to obtain the temperature distribution and deformation response of the composite beam–slab assembly. The finite element model is validated by comparing the predicted and measured thermal and structural response parameters of three composite beam–slab assemblies tested under fire conditions. The comparisons show that the proposed model is capable of predicting the fire response of beam–slab assemblies with good accuracy. Research from the analysis clearly shows that the composite action between the beam and slab significantly enhances the fire performance of composite beam–slab assemblies. It is concluded that the proposed finite element model could be used as a feasible tool to evaluate the fire response of composite floor systems.

Highlights ► An approach for modeling the fire response of beam-slab assemblies is presented. ► Predicted response parameters from the FE model are compared against test data. ► Beneficial effect of slab on fire resistance of composite assemblies is illustrated. ► Feasibility of unprotected beams in composite floor assemblies is demonstrated.