Experimental study of deflection of steel fibre reinforced concrete beams: comparison of different design codes

The flexural behaviour of steel fibres reinforced concrete (SFRC) beams is investigated using digital image correlation (DIC) technique. The deflection and curvature of the tested RC beams have been analysed by DIC technique. The experimental results in terms of deflection and other results found in the literature are compared against the predicted values using the design codes (ACI318, Eurocode 2, Russian code SP 52-101 and CAN/CSA-S806). The outcome of this study indicates that the flexural strength of beams reinforced with steel fibres is 1.15-1.25 higher than that of beams without steel fibres. Also, the deflections of SFRC beams are 15-30% higher than those of beams without steel fibres. Moreover, this study shows a good agreement between the theoretical deflections calculated by design codes and the experimental deflections for SFRC beams given by the present results. On the other hand, the codes' predictions are found to underestimate the deflections, with an average error about 1.31 for beams without steel fibres. When using a reduced modulus E(cr)equals to E-c/1.4 for high strength fibre reinforced concrete (HSFRC) beams, the ACI318 and Eurocode 2 results are found to safely predict the deflections up to load equal to 75% of the ultimate load for the HSFRC beams.