Daniele Malomo¹, Matthew J. DeJong², and Andrea Penna^{1, 3}
1)  Department of Civil Engineering and Architecture, University of Pavia, Via Ferrata 3
Pavia, 27100, Italy
e-mail: daniele.malomo01@universitadipavia.it, andrea.penna@unipv.it
2)  Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, CB2 1 PZ,
United Kingdom
e-mail: mjd97@cam.ac.uk
3)  European Centre for Training and Research in Earthquake Engineering (Eucentre), Via Ferrata 1,
Pavia, 27100, Italy
e-mail: andrea.penna@eucentre.it

Keywords: unreinforced masonry; in-plane; numerical modelling; distinct element method

Abstract. Masonry is one the most employed building materials, and there is a large population
of existing and historical unreinforced masonry (URM) constructions in earthquake prone regions all over the world. The lateral capacity of shear walls significantly affects the overall behaviour of both unreinforced and masonry-infilled RC frame buildings. However, a given unreinforced masonry panel subjected to in-plane loading may exhibit different failure modes and lateral strength depending on several factors, including boundary conditions, aspect ratio, and vertical overburden. Thus, experimental testing plays an important role in investigating the in-plane behaviour of URM elements under controlled conditions. Moreover, experiments provide important data to calibrate advanced numerical models able to predict the variability of failure modes by accounting for the interaction between masonry components (i.e. units and mortar). In this work, the Distinct Element Method was employed to model the lateral capacity and the local failure mechanisms exhibited by seven full-scale unreinforced clay and calcium silicate brick masonry wall specimens tested at Eucentre (Pavia, Italy) in 2015/2016, which were subjected to in-plane cyclic shear-compression loading sequences. The employment of the numerical tool is described, as well as the specific computational strategy developed for considering unit, joint and combined in-plane failure mechanisms. The results indicate that the proposed methodology adequately predicts the failure mechanisms and ultimate capacity of different types of masonry under a variety of different loading scenarios.