A shake table protocol for seismic assessment and qualification of acceleration‐sensitive nonstructural elements

Abstract

A shake table protocol for seismic assessment and qualification of accelerationsensitive nonstructural elements (NEs) is developed. The paper critically reviews existing protocols and highlights their criticalities, pointing out the need for the development of novel assessment and qualification approaches and protocols. The protocol is developed in light of these criticalities, considering the most recent advances in the field and the specific expertise of the research team. The most significant and contributing parts of the developed protocol consist of the definition of novel required response spectra and the generation of signals for seismic performance evaluation tests. The reliability and robustness of the protocol are evidenced in the paper considering real-floor motions as a reference, also proving the superiority of the developed protocol with respect to the reference alternatives. The defined approach and procedures are generally applicable and easily extendable to different case studies, as the process is highly versatile and modifiable. The implementation of the developed approach and protocol in the literature and in practice will significantly enhance seismic assessment and qualification of acceleration-sensitive NEs. This will possibly have a strong impact on public safety and economy.

Performance‐based seismic classification of acceleration‐sensitive non‐structural elements

“…These constraints are the following. (1) The ratios of A flexible to A rigid , implicit in the procedure outlined in Section 4.2, may not be representative of the same ratios observed for real floor motions and may be underestimated by Equations () and () 30,31 . However, as the analysis presented in Section 4.3 shows, this may not be a big issue when statistically considering the ratio for many buildings with a wide range of fundamental periods.…”

“…The second step necessary to develop a seismic classification procedure for NSEs in Italy based on seismic qualification testing is the establishment of a procedure to derive the TIM. Several procedures have been developed to define TIMs for seismic qualification shake table testing 27,30,31 . One of the most well‐known procedures to derive a TIM is the one defined by the AC 156 loading protocol 27 and is recommended in this study for the derivation of the TIMs to be used in the seismic classification procedure of NSEs in Italy.…”

“…However, as the analysis presented in Section 4.3 shows, this may not be a big issue when statistically considering the ratio for many buildings with a wide range of fundamental periods. Nonetheless, the analysis presented herein is limited to one structural typology and one site so that this is a topic that remains open for further research 30,31 . (2) The value of 5% damping ratio, implicit in the procedure presented in Section 4.2, may not be realistic for many typologies of NSEs 8,10 .…”

“…Although other NSEs should be included into the proposed seismic classification procedure, this is also a limitation of seismic qualification shake table testing of NSEs which is usually directed at such equipment. All the limitations presented here point to the fact that better and more specific seismic qualification procedures for NSEs are needed in order to adequately capture their performance 30,31 . Note that damage accumulation in the specimens is not an issue of the proposed seismic classification procedure for NSEs in Italy, since it is common in qualification shake table tests to test one or more specimens only to the required seismic intensity level and not to all the seismic intensity levels of the procedure.…”

“…Further work is still required to define appropriate levels of accelerations for qualification shake table testing of NSEs. The reader is referred to Zito et al 30,31 for an expanded discussion on the latter topic.…”