Comparison of different design guidelines for steel fibre reinforced concrete (SFRC) structures

Abstract

One of the main reasons for the limited use of steel fibre reinforced concrete (SFRC) in load-carrying structures today is the lack of accepted design guidelines. The Norwegian Concrete Association (Norsk Betongforening) are currently working on the publication NB38 - Guideline for design, execution, and control of fibre reinforced concrete in load-carrying structures, and a new version of EN 1992-1-1 is on it's way. Both of them include design guidelines for fibre reinforced concrete.

The primary aim of this thesis is to compare the new guidelines, along with existing guidelines, with respect to their calculations for shear resistance and crack-width. A theoretical study is carried out, comparing the theoretical shear resistance and crack-width for concrete classes defined in EN 1992-1-1:2018 Annex L.

For crack-widths, results from EN 1992-1-1:2018, NB38, and FIB Model Code 2010 are compared theoretically and for shear capacity, calculations from the different guidelines are compared to each other, as well as to results from finite element analyses.

The results show that the differences between the guidelines are vast, both for crack-widths and shear capacity. It is shown that some of the guidelines dramatically overestimate the contribution of fibres to the load-bearing capacity, while others underestimate it.