Use of tension softening diagrams for predicting the post-cracking behaviour of steel fibre reinforced concrete panels

In this paper, a semi-analytical model aimed to investigate the post-cracking behaviour of FRC panels is presented. The model is based on force equilibrium in the critical cracked section and uses an arbitrary tension softening diagram as input. An additional relation that links the crack length parameter to the deflection needs to be determined. Due to the random fibre distribution and others uncertainties involved in concrete mix, deterministic approaches are not suitable for deriving the missing relationship for panels. The load deflection response is predicted using yield line theory based on the crack length parameter normalized-deflection diagram developed from the analysis of beams having the same thickness using Monte Carlo simulation (MCS) technique. The proposed approach is applied to a square panel supported on four corners with a comparison to an existing theory based on predefined parabolic softening law. A good agreement has been found between the model predictions and finite element calculations.