A masonry catalogue for the Groningen region

Human induced seismicity has become an uprising problem in the Groningen region of The Netherlands, in which the vast majority of buildings are non-seismically engineered unreinforced masonry houses. In order to accurately assess the seismic vulnerability of these buildings, a characterization of the constitutive masonry is required. In 2015, as a part of a larger project, a campaign on the material characterization of existing buildings was performed, including laboratory and in-situ testing of the masonry walls. The campaign constitutes the germ for the creation of a regional material properties database. 16 buildings were tested in total, comprising residential structures and schools, dating from the early ‘20s to 2005. The constitutive walls included both clay and calcium silicate brick masonry of various qualities and conditions. The in-situ testing included non-destructive tests such as rebound hammer and sonic tests, and semidestructive test, i.e. flat jack and shove test. Samples were carefully taken to the laboratory, where the destructive campaign took place, including compressive, flexural, shear and bond wrench tests. Despite of the limited number of sampled buildings, the campaign provided a better insight of the researched material. The available data suggests that the use of sub-typologies (e.g. depending of the masonry quality or condition) could reduce the dispersion on the results. A first attempt of correlation between in-situ and laboratory tests is proposed, which could benefit from further calibration. In this paper, the material characterization campaign is described, and the main outcomes are discussed