Title: Influence of the Post-Cracking Residual Strength Variability on the Partial Safety Factor

Author(s): de la Fuente, A.; Cavalaro, S.H.; Bairán, J.M.

Publication: Symposium Paper

Volume: 343

Issue:

Appears on pages(s): 371-380

Keywords: FRC; partial safety factor; post-cracking strength; structural reliability

DOI:

Date: 10/1/2020

Abstract:
The use of fibre reinforced concrete (FRC) in structural applications is increasing mainly due to improvements on the material technology and its acceptance in design codes (e.g., fib Model Code 2010). In that sense, the design of FRC is usually dealt with the same safety format established for reinforced concrete. In fib Model Code, for instance, the same magnitude of the partial safety factor for FRC compressive (fc) and post-cracking flexural (fR) strengths is assumed (1.50). It must be noticed that this assumption might be unrealistic, and on the unsafe side in terms of structural reliability, since fR present higher intrinsic scatter (variability due to fibre orientation, distribution, dosage) than fc. However, it has been experimentally and numerically confirmed, that this scatter decrease with the width of the cracked surface, so this assumption has lesser impact in structural elements with large cracked regions involved in the failure mechanism (e.g., slabs). The goal of this research is twofold: (1) to assess the influence of the width of the cracked region on the variability of fR and (2) to calibrate partial safety factors for fR based on the different target reliability indexes proposed in the fib Model Code 2010 for ultimate limit states and the variability obtained in the characterization tests.