A MODEL FOR VULNERABILITY ANALYSIS OF SLENDER TOWERS MADE OF NO TENSION MATERIAL

This paper deals with a numerical model to analyse transverse vibrations of one-dimensional structures, made of no-tension material. The model is developed considering a non-linear constitutive equation for rectangular cross-section beams, which assumes material’s no tensile strength and limited compressive strength. The obtained numerical model, still accounting for the main mechanical characteristics of masonry, leads to overcome some difficulties encountered in dynamic analysis conducted by means of refined masonry-like models, as it results more effective and lighter in processor usage. Moreover, in order to obtain a numerical model simple enough to perform a large amount of parametric analysis, a further simplification has been made. By assuming the axial force known, a non-linear constitutive law expressing the bending moment as a function of the beam curvature only has been developed, so that transverse motion can be uncoupled from the axial one. The model allows for analysing non-linear response of masonry slender structures with primarily flexural behaviour, such as isolate ancient towers, under horizontal input ground motions. The model seems to be very effective to supply information about both global and local structural damage, mainly when damage patterns involve the entire structure; to this end, different likely parameters indicative of damage are proposed.