This work compares the ability of different numerical modelling approaches to simulate the out-of-plane behaviour of two-leaf stone masonry walls with different masonry bond configurations: an irregular drystone stone masonry wall and a masonry wall with roughly cut regular stone units. Finite element modelling, considering both a micro and macro-modelling approach, and the distinct element method have been compared in this study, which intends to (i) provide an insight regarding parameter estimation and the calibration procedure for each modelling approach considered; (ii) highlight their pros and cons of the selected modelling strategies; (iii) further expand the existing literature addressing the numerical modelling of two-leaf stone masonry walls.

Bed joint reinforced repointing is a retrofitting technique for unreinforced masonry structures that is commonly applied in the Netherlands to repair settlement-induced damage. Using this technique, the bed joints of masonry walls are reinforced with steel rebars that are embedded in a high strength repair mortar. Due to the increase of induced seismic events in the northern part of the Netherlands, an experimental study was carried out at Delft University of Technology to investigate the performance of this retrofitting technique for combined settlement and seismic loading. This paper aims to simulate the experimental results, with a focus on the comparison of different finite element modelling approaches for studying both un-strengthened and strengthened full-scale tested walls. To that end, three different models are investigated – comprising both macro (continuum) and simplified and detailed micro (brick-to-brick) modelling approaches. The bricks and mortar joints are modelled as one homogenous continuum in the macro model, whereas in the two brick-to-brick models these structural components are modelled separately, with the detailed model including interface elements to simulate the brick–mortar bonds. Nonlinear pushover analyses are subsequently carried out using all three modelling approaches, for both monotonic and cyclic loading cases. Based on these analyses, the detailed brick-to-brick model was found unsuitable to simulate the strengthened wall because cracks in the model mainly occur in the form of opening of the brick–mortar bond interfaces, while smeared cracking in the plane stress elements of the mortar joints is very limited. Similarly, the continuum damage model was found to be inaccurate when pre-existing damage in the experiment needed to be taken into account. The continuum damage model also showed lower axial stresses in the rebars, compared with the simplified brick-to-brick model, as the former does not allow for the direct assignment of material properties for the high strength repair mortar in the strengthened joints.

Failure of tall slender masonry structures during earthquakes often involves partial collapse of the structure well-above ground level. Consequently, the elastic response of the structure needs to be considered, which often requires modal analysis using finite element models — the generation of which can be labour-intensive and time-consuming. This paper presents a new integrated modelling approach which combines finite element analysis with rocking dynamics to model the seismic response of complex structural geometries in a computationally-efficient manner. The modelling strategy is implemented within the open-source computational framework COMPAS and is incorporated within the broader framework of a tool being developed for the seismic collapse assessment of masonry structures. The framework of this tool is first outlined, and the utility of the new modelling approach then demonstrated through application to the seismic assessment of a three historic masonry towers in North-Eastern Italy. The importance of accounting for elastic amplification effects, as well as the influence of varying boundary conditions on the dynamic response, is also illustrated.