Geometric indices to quantify textures irregularity of stone masonry walls

This paper aims at developing a general methodology supported by quantifiable geometric indices to classify the irregularity of stone masonry walls by direct observation of the elevation texture. This classification is based on indicators proposed in procedures developed in Italy, complemented with new tools and criteria. In particular, the evaluation of the geometric irregularity is done through a set of partial indices that consider the stones' shape, size and their organization along horizontal and vertical alignments. The methodology was applied to twenty-four granitic stone masonry walls selected from old buildings located at Porto city centre, in Portugal, and a classification is proposed based on irregularity levels graded according to the ranges of the different indices found for these walls.