Daniele Losanno

Monitoring and Identification of the Seismically Isolated “Our Lady of Tears” Shrine in Syracuse

This paper describes the installation and management of the monitoring system of the “Our Lady of Tears Shrine” in Syracuse, whose dome is an imposing r.c. and prestressed r.c. structure of about 22,000 ton that was seismically isolated by flat sliding devices with hysteretic dampers. The monitoring system, representing an upgrading and improvement of an old system never made working, has some innovative features, because it allows to manage with the same dedicated hardware and software both the slow (thermal variations, relative humidity, wind direction and velocity) and the fast acquisitions (dynamic vibrations by wind and earthquake). The monitoring system was inserted among those structures maintained and controlled by the Seismic Observatory of Structures of the National Department of Civil Protection. Some records of low magnitude earthquakes allowed to validate the correct behaviour of the whole structure, as well as to make a dynamic identification of the complex construction and to calibrate a detailed finite element model of the Sanctuary, thus predicting isolators’ behaviour under design earthquake.

Design and Retrofit of Multistory Frames with Elastic-Deformable Viscous Damping Braces

ABSTRACT This paper provides an exhaustive treatment for the analysis of non-proportional damping structures equipped with elastically deformable viscous damping braces. A frequency domain approach is adopted for solving the equation of motion as a function of nondimensional parameters. Accounting for the brace flexibility, an optimal damping system is suggested in order to minimize the resonance peak of the top-story displacement response on the first vibration mode. The effect of variation of the dissipative bracing system is demonstrated not only in terms of provided equivalent viscous damping and maximum response, but also in terms of dominant frequency and mode shapes.

An application of SHMS to a passively controlled structure

This paper is focused on the study of the “Our Lady of Tears Shrine” in Syracuse, which was subjected to a seismic isolation intervention and the successive installation and management of a structural monitoring system. The monitoring system, representing an upgrading and improvement of an old system never made working, has some innovative features, because it allows to manage with one and the same dedicated hardware and software both the slow (thermal variations, relative humidity, wind direction and velocity) and the fast acquisitions, namely those dynamiccaused by earthquake, wind and environmental vibrations. The monitoring system has been recently inserted among those structures maintained and controlled by the National Department of Civil Protection within the Seismic Observatory of Structures. Some records of recent low magnitude seismic events allowed to validate the correct behavior of the whole structure, as well as to make a dynamic identification of the complex construction. A complex FEM model has been used to predict the structural behavior under strong motions and evaluate the effectiveness of the seismic retrofit.