Fibre Bragg grating based acoustic emission measurement technique is employed to monitor crack activity in civil engineering structures and sites. The feasibility and effectiveness of using fibre optic methods for crack activity monitoring is demonstrated with three example cases (a) railway ballast breakage (b) cold crack monitoring in welding (c) crack activity monitoring in rock samples. The successful laboratory demonstration results of the method shows the potential of using fibre optic acoustic emission method to monitor crack activities that can ensure the structural integrity of civil engineering structures. This will lead further large scale testing and validation of the technique.