Empirical approach to determine the residual flexural strength
When designing steel fibre reinforced concrete, the designer determines the performance classes of the steel fibre reinforced concrete (residual flexural strength L1 and L2) as basic properties on the basis of the DAfStb guideline ”Steel Fibre Reinforced Concrete“. In practice, it often turns out to be difficult to establish the relationship between performance classes and required steel fibre content depending on the type of steel fibre and the concrete quality. In order to make it possible for manufacturers as well as for designers and controllers to estimate the steel fibre content likely to be required, various empirical approaches exist for the approximate determination of the residual flexural strength of steel fibre reinforced concrete. However, they were derived on the basis of different tests and almost exclusively on the basis of few or ”own“ test results of the respective research centres, which is why a limited validity of the respective proposed approximation approach is available. Using the database ”steel fibre reinforced concrete“ on flexural beam tests, these approaches were systematically analysed and – on the basis of this – a modified approach for determining the residual flexural strength of steel fibre reinforced concrete was developed, which is reported in the article.