Structural systems composed of cast in situ sandwich squat concrete walls, which make use of a lightweight material (for example polystyrene) as a support for the concrete, are widely used for construction in non seismic areas or in areas of low seismicity, and appreciated for their (i) limited constructions costs, (ii) limited installation times, (iii) great constructions flexibility and (iv) high energy and acoustic efficiency. Also, these systems have been recently used within the re-construction program in the Abruzzo region after the L’Aquila earthquake of 2009. However their seismic behavior has not been fully investigated, with most of the research work accomplished up to date being focused upon the seismic behavior of slender shear walls. Whilst for cantilever slender structural wall systems a lot of research works is available, for the structural systems composed of squat concrete walls only few research works are available, despite the fact that these types of building structures have shown, in general, valuable strength resources towards earthquakes of high intensity. If these cast-in-situ squat concrete walls are assembled with appropriate connections, a cellular/box behavior of the structural system is obtained which leads to high strength resources (which allows not to use the post-elastic behavior and the ductility resources) and high torsional stiffness.

In recent years, an exhaustive experimental campaign was carried out by the University of Bologna (in charge of the design and interpretation of the tests) and the EUCENTRE labs in Pavia (in charge of the test themselves). The effort was devoted to the assessment of the structural performances of single panels composed of cast-in-situ sandwich squat concrete walls. In order to obtain a correct characterization of the seismic behavior (stiffness, strength, ductility, energy dissipation) of such structural elements, a number of tests were performed upon two-dimensional (3.0 m by 3.0 m) cast-in-situ sandwich squat concrete walls (with and without openings). In the experimental tests, a number of horizontal in-plane loading cycles were imposed to the specimens, while the vertical load was kept constant. The results obtained have shown that the tested elements are characterized by: (i) absence of a real failure; (ii) high values of the maximum horizontal load applied to the structural systems (higher than the applied vertical load); (iii) residual bearing capacity with respect to the vertical loads, also when large lateral deformations were developed; (iv) a good degree of kinematic ductility.

Shaking table tests are currently under design and development to validate the theoretically and partially-experimentally anticipated (through cyclic tests under horizontal loads) good seismic behavior of cellular structures composed of cast in situ squat sandwich concrete walls. These tests will be performed, at the laboratory facilities of the EUCENTRE in Pavia. The structural specimen which will be tested is a full-scale 3-storey structural system composed of cast-in-situ squat sandwich concrete walls characterized by 5.50 x 4.10 meters in plan and 8.25 meters in height.

This paper describes all the phases and the technical problems which occurred in the design process of this specimen as it should: (i) be representative of common real built structures (squat configuration of the walls); (ii) be easily transportable from the construction site to the table (this involves the design of specific lifting and lowering systems); (iii) lead to significant results (carried out up to the collapse of the walls, in order to capture also the post-yielding behavior and the ductility resources); (iv) not damage the shaking table (analytical and numerical prediction of the specimen behavior should be developed). Various solutions have been proposed and here detailed for both the specimen and the foundation systems, before reaching the final setup.