NONLINEAR FE ANALYSIS OF A MASONRY SPIRAL STAIRCASE IN NISIDA: A REFINED NUMERICAL CASE STUDY

Following previous work by some of the present authors based on the linear arch static analysis (LASA), which models the masonry material as a no-tension material according to Heyman (Heyman, J., The Stone Skeleton, Int. J. Solids Struct., vol. 2, no. 2, pp. 249–279, 1966) and on the safe theorem of the limit analysis (LA), an in-depth numerical study of a case study based on a masonry spiral staircase in Nisida, near Naples, is here presented by means of an accurate finite element (FE) model. The nonlinear FE model has been obtained by the use of the ANSYS Parametric Design Language (APDL), and a precise representation of all the material involved and of the boundary conditions, has been obtained. The results confirm that LASA can be an alternative to much more complex numerical analyses, such as FE, but it cannot account for the main cause of collapse or stress redistribution in these type of structures, that is sagging and subsidences. The results are presented and discussed in some detail.