Validation of a practice-oriented floor spectra formulation through actual data from the 2016/2017 Central Italy earthquake

Abstract

Analytical expressions for the floor spectra evaluation play a key role in the correct definition of the seismic input induced to non-structural elements or local mechanisms in existing buildings. They have to be able properly assessing the possible amplification phenomena, but also correctly describing the effects of nonlinearities due to structural damage. Due to the complexity of such phenomena, data on existing structures hit by earthquakes constitute a precious source for a better understanding of the topic and the validation of analytical expressions. In this framework, the paper aim is twofold. On one hand, it evaluates the entity of seismic amplification through experimental evidences from in-situ measurements on two existing monitored unreinforced structures. On the other hand, it presents the application on them of an analytical expression for the floor spectra already developed by the Authors. The case-studies are the former courthouse of Fabriano (Ancona, Italy) and the Pizzoli’s town hall (L’Aquila, Italy). They were both hit by the 2016/2017 earthquake in Central Italy and are permanently monitored by the Italian seismic monitoring system of the Italian Department of Civil Protection. With the aim of validating the above-mentioned expression, the paper shows the comparison between experimental and analytical floor spectra for various minor events and mainshocks of the Central Italy earthquake. Since the two case-studies exhibited different damage levels (from slight to moderate, respectively), the comparison allowed us to verify the reliability of the expression both in the pseudo-elastic and moderate nonlinear fields.