Analisi limite di cupole in muratura con tamburo e lanterna soggette a carichi orizzontali

With this work we take back an our numeric method already utilized for the evaluation of the safety of axi-symmetric masonry domes, at first carrying only its own weight and later on subjected to their own weight and to increasing horizontal loads. In the present study this numeric method has been utilized to evaluate the safety of the domes on drum, with or without lantern, and the collapse mechanism, in addition to multiplier of horizontal collapse loads, have been found. The generic dome has been discretized in rigid macro-blocks not staggered but aligned along the parallels and the meridians. This choice is justified because we refer to domes of tuffaceous masonry used in the area of Naples (Italy), for which the characteristics of stones and lime mortar are similar and make the structural material considerably homogeneous. The yield domain conditions for the quadrilateral interfaces between two macro-blocks are expressed in terms of stress resultant and the mechanical features on these interfaces are: inability to carry tension, unlimited compressive strength, sliding with dilatancy. The compiled computational program evaluates the horizontal collapse load multiplier, utilizing the static theorem of limit analysis through a procedure of optimization constrained to respect of equilibrium conditions and of the yield domains on the interfaces of macro-blocks and, in the end, finds the collapse mechanism. In the applications we have analyzed axi-symmetric masonry domes having hemispheric and elliptical shape with constant or variable thickness, and also domes obtained by an architectonic relief. The results obtained appear coherent in connection with both geometric and kinematic parameters, also if we until now have not found other works in literature to make a comparison.