Pushover analysis of an ancient masonry oil-mill in the southern Italy: a meso-macro scale model

The paper presents a meso-macro scale numerical model –within the equivalent frame approach assumption– for the pushover analysis of in-plane loaded historical masonry walls constituted by an irregular assemblage of stones. The procedure is tested on an ancient masonry oil-mill in the Southern Italy. At the meso-scale, ultimate bending moment-shear force strength domains of piers and spandrels are derived by means of a heterogeneous upper bound FE limit analysis and the results are stored in a database. Assessing the capacity of both piers and spandrels is crucial when dealing with structural elements in irregular texture, since code of practice predictions are tailored for regular assemblages of bricks only. In this framework, heterogeneous limit analysis is particularly suitable for computing failure loads, since it permits a distinct modelling of stones and mortar joints and provides limit multipliers with a very limited computation effort. Appropriate static and kinematic boundary conditions are imposed to account for the complex interaction of internal forces and deformed shapes of single elements. At the macro-scale, a frame model of a masonry building is assembled, where piers and spandrels are modelled as elastic Timoshenko beams. At each analysis step, it is required that the internal forces in each structural element are smaller than the failure loads stored in the database created at the meso-scale. In order to test the reliability and efficiency of the approach proposed, an existing real scale old masonry oilmill located in the Southern Italy is considered and one wall belonging to the building is analyzed when subjected to in-plane increasing horizontal loads up to collapse.