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.