Shake table test of suspended fire protection piping systems

Nonstructural elements housed in existing buildings have not been designed or assessed considering seismic actions, except for very few exceptions. In Italy, for example, the current building code, issued in 2018, is the first one clearly recommending the seismic design/assessment of nonstructural elements, whereas, in the previous version, issued in 2008, even though basic methodological criteria were supplied, the design/assessment was not clearly meant to be compulsory, and it was rarely carried out by practitioners. Therefore, most existing buildings, even though code-conforming, house nonstructural elements that would be extremely vulnerable to seismic actions with high probability. Suspended fire protection piping systems are typical examples of nonstructural elements that are extremely valuable (especially in critical facilities) and that can be highly vulnerable (e.g., due to no seismic design and significant masses). Bracing systems are often integrated to existing pipeline systems, which were not designed for seismic actions, to improve their seismic performance, but this solution is not always feasible due to practical issues (e.g., invasiveness and lack of space). An innovative seismic protection system is proposed in this study, consisting in innovative isolation devices that connect the suspended pipeline system to the building floor. Shake table tests are carried out to assess the seismic behavior of both traditional and proposed innovative strategies. The tests are performed considering an innovative testing protocol, compliant with the current Italian seismic demand assessment formulation. The paper reports the preliminary results of the tests, showing the potential effectiveness of the seismic isolation devices tested in the study.