Experimental failure analysis of shear-critical ordinary and steel-fibre prestressed concrete beams using optical measurement techniques

Although the use of fibre reinforced concrete (FRC) for structural applications is continuously increasing, it is still limited with respect to its potentials.This can be mainly attributed to the lack of international building codes for FRC structural elements.This paper aims to contribute to the development of suitable design principles for shear in FRC elements by presenting the preliminary results of 6 full-scale pretensioned steel-fibre reinforced concrete members.The main investigated parameters are the amount of prestressing, the amount of shear reinforcement and the fibre dosage respectively.All specimens are subjected to a four-point bending test until failure.Traditional mechanical measurement devices are used in combination with advanced optical measurement systems (i.e.stereo-vision digital image correlation 3D DIC and Bragg grated optical fibres).Apart from the full-scale tests, a number of small-scale experimental investigations are performed to characterize the material properties.The experimentally determined results are compared to predictions using analytical models found in Eurocode 2 (EC2) and Model Code 2010 (MC2010).Based on the obtained full-field data from the DIC systems and the detailed deformation information obtained from the Bragg grated optical fibres, an assessment is made of the mechanical behaviour.