Non-linear modelling of masonry structures: Application to the case study of the carmine bell tower

The non-linear behaviour of an ancient masonry bell tower was investigated by means of a refined three-dimensional Finite Difference Model developed in the software FLAC3D. The Carmine Bell Tower is a monumental one located in the city of Napoli characterized by a slender architectural configuration and made of two types of masonry: tuff blocks and clay bricks. The non-linear behaviour of the masonry materials was introduced through a constitutive model based on a Mohr-Coulomb shear surface combined with a tension cut-off and a linear compression limit. The target stress-strain curves were reproduced by simulating uniaxial compression and tensile tests on masonry samples. The effect of the variation of both the shear-limit and compression-limit surfaces was investigated. After the calibration of the constitutive model, push-over analyses were carried out in order to assess the displacement capacity of the Tower as the constitutive model changes.