ABSTRACT
Cracking in masonry can be introduced by differential settlements, vibrations and impact, temperature and load-induced stresses. Crack width evolution is to be monitored to assess the damage progress and ascertain the structural integrity of the monument. Traditional crack monitoring devices crack width meters, linear variable displacement transducers and demountable mechanical strain gauge measurement points have certain drawbacks. In a search for novel, integrated and accurate monitoring techniques for crack measurements in masonry, different techniques have been applied on a masonry wall during an experimental three-pointbending test. In comparing the results of the different monitoring techniques temperature influences and possibilities for on-site application. The use of novel monitoring techniques, including Bragg grated optical fibres and stereo-vision digital image correlation, were used during the tests. Optical fibre with distributed fibre Bragg grating sensors Strain monitoring with optical fibres engraved with Bragg gratings relies on the analysis of the wavelength spectrum which is reflected by the Bragg gratings.
