Investigating the Shear Behaviour of Reinforced Concrete Beams during Fires Using Finite Element Analysis

摘要

A detailed 3-Dimensional time domain transient thermal stress finite element analysis was carried out to investigate the shear behaviour of reinforced concrete beams exposed to fire attack. A FE model that represented a simply supported reinforced concrete beam was developed. The beam was subjected to BS574 standard fire exposure to the bottom and side surfaces, in the form of transient temperatures versus time, while maintaining constant transverse loading on top surface of mid span. Material nonlinearity was taken into account because of the changes in material properties experienced in fire. The more complicated aspects of structural behaviour in fire conditions, such as thermal dilation, cracking or crushing of concrete and yielding of steel were modelled. The validation of the applicability of the FE model was illustrated by comparing the finite element solution with the results of experimental testing carried out for similar RC beams within the same boundary conditions. The FE analysis gave acceptable results in terms of performance, development and progression of diagonal shear cracks, shear capacity, and mode of failure.