MAZZOTTI, CLAUDIO1; SASSONI, ENRICO2; RINALDINI, VALENTINA3

1 Prof. Claudio Mazzotti, University of Bologna, Department of Civil, Chemical, Environmental and Materials Engineering, claudio.mazzotti@unibo.it

2 Dr. Enrico Sassoni, University of Bologna, Department of Civil, Chemical, Environmental and Materials Engineering, enrico.sassoni2@unibo.it

3 Valentina Rinaldini, University of Bologna, Centro Interdipartimentale di Ricerca Industriale (CIRI) Edilizia e Costruzioni, valentina.rinaldini@unibo.it

In this study, a comparison between three different moderately destructive techniques for evaluating masonry shear strength is presented using a study case. The studied building is the Museum of Zoology in Bologna (Italy), dating back to the ‘30s and built using fired-clay solid bricks and mortar. Masonry shear strength with zero vertical stress and angle of internal friction were evaluated by the following three methods: (1) measuring on-site the horizontal force necessary to cause the displacement of a brick, according to ASTM C1531-09; (2) subjecting masonry cores, made of two bricks and a diametric mortar layer, to splitting test with mortar layer rotation by various degrees, according to a novel methodology recently proposed by the authors; (3) calculating masonry shear strength from the compressive strength values of the constitutive bricks and mortar, tested separately, according to Italian code for constructions. While values provided by method (3) are characteristic values, hence hardly comparable to values provided by the other two methods, the results of the study indicate a fair agreement between shear strength found by methods (1) and (2). In particular, testing of masonry cores with mortar layer rotation is confirmed as a promising method for masonry shear strength determination.

Keywords: Seismic vulnerability, shear strength, on-site testing, moderately destructive testing, masonry cores