Description
This study aimed to investigate the cracking behaviour of RC beams strengthened by external bonded smart FRP. A smart CFRP consists of two texture fabrics inside which a distributed fibre-optic sensor (DFOS) is inserted. During the test, the sensor measured the mechanical strain distribution of the composite with a millimetric spatial resolution. Simultaneously crack openings along the beams were detected and measured using digital image correlation (DIC).
The results of the strengthened beams were compared with reference values, and the crack width was compared with the theoretical values predicted using the Eurocode 2 (EC2) formula, calibrated for non-strengthened RC elements. Subsequently, an empirical model was established as a modification of EC2, considering the presence of a CFRP system. The corresponding results were compared and discussed to validate the model.
A smart CFRP was described and implemented in the tested beams and was used to measure the bond stress at the interface and cracks location. Strain and shear bond stress profiles have been reconstructed for a reference beam showing consistent results. This proposed model constitutes a monitoring process for CFRP-reinforced beams. The measurement of strain profile allow then to obtain the level of beam damaged during a loading.
