The lower-bound limit analysis of arbitrary systems of masonry arches and buttresses is addressed. Main mo- tivation is the observation that, not only the position, but also the orientation of the failure sections in an arch or a buttress might not be known in advance in practical applications. To overcome the limitations stemming from the classical notion of element with prescribed stereotomy, the original model of monodimensional masonry structural element with multiple potential failure sections with different orientations is introduced. Accordingly, the lower-bound limit analysis problem for systems of masonry arches and buttresses is formulated as a straightforward linear programming problem. The predicting capabilities of the proposed...