ABSTRACT
Ties in masonry arches and vaults play a key role in constraining their horizontal thrust. This chapter focuses on vault ties and presents a study of existing iron ties in several historical constructions. Indications obtained by the initial analyses of the ties in historical constructions database hence suggest behaviour closer to beams than cables, with stiffness of the element deeply affecting the overall behaviour. The analyses carried out indicate a stress level which is generally compatible with the material strength. This observation is consistent with the lack of available theoretical models at the time of construction, and then the related relatively conservative stress/strength conditions found. Estimation of the axial tension in historical ties is a more complex task with respect to cables used for tensile structures, mainly due to the not negligible stiffness of the tested element. The dynamic methods rely on relations based on stiffness and mass rather than on those which explicit the axial force.
