This paper describes a programme of research into the application of the dynamic stiffness technique, based upon the frequency response function, for investigating the integrity of masonry arches. Brief accounts are given of the theoretical basis, the test procedure and the analysis technique. The experimental programme is discussed and various results are presented which demonstrate the influence of applied loading on the dynamic stiffness of prototype masonry arches. The results obtained from a sound and a defective arch are compared. It is concluded that the dynamic stiffness technique provides a rapid and effective means of assessing the physical condition of masonry arches.
