Dynamic testing of a mixed RC-URM building

The seismic behaviour of a mixed reinforced concrete (RC) - unreinforced masonry (URM) structure has been investigated through shake table testing. Though quite common in practice, these structures were not tested in the past: experimental data about their behaviour is therefore currently lacking. The tested specimen was a 1:2 scale four storeys building subjected to unidirectional motion. The building, designed following the modern design codes, was 5.50 m by 3.20 m in plan with an inter-storey height of about 1.50 m. The load-bearing elements were six URM and two RC walls coupled by the RC storey slabs, only two of the URM walls were out-of-plane loaded. Multiple shaking at increasing intensity alternated with structural dynamic identification allowed the verification of the seismic performance of the investigated structure. Traditional acquisition transducers, such as potentiometers and accelerometers, were used together with a machine vision system for the monitoring of the structure during the tests. The paper reports the preliminary results derived by the interpretation of the acquired data. Outcomes in terms of decay of the storey secant stiffness displacement profiles and dynamic amplification of the acceleration will be presented together with information about the period shift shown by the structure