Evaluation of shear strength prediction models for polypropylene fiber-reinforced concrete beams without stirrups: Influence of residual tensile strength estimation on fib-MC2010 code predictions
Abstract
Predicting the shear strength of polypropylene fiber-reinforced concrete (PFRC) beams remains challenging because most formulations were calibrated using steel fiber-reinforced concrete (SFRC) data, while post-cracking tensile properties required by design models are rarely reported for PFRC members. This study evaluates analytical and code-based models using a database of 98 PFRC beams without transverse reinforcement. The evaluated formulations included analytical models and the RILEM TC 162-TDF, DAfStB, and fib Model Code 2010 approaches. Particular attention is given to fib Model Code 2010, which requires residual tensile strength parameters unavailable for most specimens. Therefore, three alternative procedures were used specifically within the fib Model Code 2010 framework to estimate these parameters. The resulting estimates were incorporated separately into the same shear resistance equation to quantify their influence on predicted capacity. Performance was assessed using the mean experimental-to-predicted shear strength ratio, coefficient of variation, root mean square error, coefficient of determination, mean absolute error, and distributions of safe and unsafe predictions. Considerable differences were observed among the models. Among the analytical formulations, the model proposed by Arslan et al. provided the most balanced performance, whereas DAfStB exhibited the weakest predictive capability. The three fib Model Code 2010 implementations produced substantially different results despite using the same shear resistance equation. The findings show that fib Model Code 2010 predictions are highly sensitive to the residual tensile strength estimation procedure. Reliable PFRC-specific characterization of post-cracking tensile behavior is therefore essential for improving design-oriented shear strength predictions.
Keywords
References
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