F. Portioli1, L. Cascini2, R. Gagliardo2, R. Landolfo2
1)  Dept. of Structures for Engineering and Architecture, University of Naples Federico II
via Forno Vecchio 36, 80134 Naples, Italy
e-mail: fportiol@unina.it
2)   Dept. of Structures for Engineering and Architecture, University of Naples Federico II
via Forno Vecchio 36, 80134 Naples, Italy
e-mail: lucrezia.cascini@unina.it, raffaele.gagliardo@unina.it, landolfo@unina.it

Keywords: Masonry block structures, Settlement, Support collapse displacements, Rigid block modelling, Incremental limit equilibrium analysis, Linear programming.

Abstract. This paper is devoted to the development of a discrete rigid block model for the assessment of dry-jointed masonry structures subjected to foundation settlements or spreading support in the large displacement regime.
The numerical model is a two-dimensional assemblage of rigid blocks interacting at no tension, frictional contact interfaces with infinite compressive strength. Failure conditions at interfaces include both opening and sliding failure. The numerical formulation was developed in the framework of incremental limit equilibrium analysis and mathematical programming was used to solve the associated contact problem. As such, few geometrical and mechanical parameters govern the response of the numerical model, such as rigid block configuration, load distribution and friction coefficient, leading to efficient and robust computational solutions.
Experimental tests were carried out on a small-scale panel with opening subjected to imposed settlements to validate the proposed model. Comparisons in terms of failure modes and maximum allowable support displacements just before the collapse are presented. On the basis of the obtained results, the accuracy and the computational efficiency of the formulation adopted are discussed.