Establishment of Suitable General Probabilistic Model for Shear Reliability Analysis

Adequate characterization and quantification of the model uncertainties in shear resistance models are identified as one of the key issues in reliability analysis of shear reinforced concrete beams. Previous studies indicate high model uncertainty in shear prediction. Model uncertainties for various shear predictive models are characterised here, based on a recent and well-vetted database of shear failures. The characterisation includes the estimation of main statistical parameters; and importantly also correlation and regression analysis to assess the consistency of model uncertainties over ranges of design parameters. The aim is to identify models suitable for use as a general probabilistic model (GPM) in future reliability assessments. The Variable Strut Inclination Method (VSIM) displayed high bias, variability and various correlations with shear input parameters which make it an unsuitable choice for GPM. The modified compression field theory (MCFT) showed low bias and variability with consistent model uncertainties over the ranges of shear design parameters and is thus suitable as GPM.