Preliminary centrifuge tests on unreinforced masonry buildings built using a sand-based 3D printer

Shake table centrifuge testing of small-scale physical models is useful for geotechnical and structural engineers. However, at scales on the order of 1:15, creating physical models of unreinforced masonry (URM) structures is challenging from a practical point of view, and with respect to scaling. The response of URM is stress-dependent, and therefore, centrifuge modeling is ideally suited to maintain the proper stress level and alleviate scale effects. This paper presents a preliminary centrifuge model test on URM buildings, built using a sand-based 3D printer, aiming to solve manufacturing problems at a small scale. Since 3D printers can only handle a single material, the modeling of mortar joints is conducted through precise control of the micro-geometry of the printed material at joint locations, essentially emulating joints with notches. A unidirectional seismic action is applied using a shaking table mounted on the geotechnical beam centrifuge of the ETH Zurich Geotechnical Centrifuge Center (GCC). A preliminary test is presented and the results are compared to a similar full-scale test from the literature. The response of the centrifuge models is evaluated based on acceleration response, damage, and collapse mechanisms, in function of an increasing intensity earthquake testing protocol.