MS22.3 - Vibration-Based Assessment and SHM of Cultural Heritage Structure

The actual dynamic behavior of the masonry civic Clock tower in a little village, heavily damaged by the recent 2016 seismic sequence of central Italy, is thoroughly investigated by means of a detailed numerical model built and calibrated using the experimental modal properties obtained through Ambient Vibration Tests. The goal is to update the uncertain parameters of the Finite Element Model (elastic moduli, mass densities, constraints, and boundary conditions) to minimize the discrepancy between experimental and numerical dynamic features. Due to the high nonlinear dependency of the objective function of this optimization problem on the afore-mentioned parameters, and the likely possibility to get trapped in local minima, a fully automated Finite Element Model Updating procedure based on genetic algorithms and global optimization is used, leading to the successful estimation of the uncertain parameters of the tower. The results allowed to create a reference digital replica of the current structural condition of the tower and to set the performance standards that will help to optimize the control of the structural integrity over time.

This paper focuses on an experimental monitoring system developed for the Temple of Neptune in Paestum within a joint research project carried out by the Department of Civil Engineering (DICIV) at the University of Salerno and the Archaeological Park of Paestum and Velia (PAEVE).This monitoring system is an innovative seismometric network consisting of mechanical and electronic components of high sensitivity and precision, allowing the assessment of the static and dynamic response of the structure in order to monitor its evolution over time and support proactive maintenance activities. In particular, the paper presents the monitoring network and discusses the preliminary results highlighting the contribution that such an innovative system can provide to a broader maintenance process. The results confirm the high level of accuracy and stability of the overall system, as well as preliminary correlations between the temple’s daily response and weather changes such as temperature.

Museum objects are frequently transported by road and air when toured internationally or when moved between storage facilities which exposes them to a range of vibration and shock inputs. Many of these vulnerable objects have incipient damage such as cracks, loose joints, partial delamination or failing repairs which can be exacerbated in transit. It is the conservator’s responsibility to select which objects are safe to travel, largely based on experience and professional judgement. A joint research programme between the University of Southampton and The British Museum aims to develop a scientific framework to aid and inform such judgements. A central research question, which is the focus of this paper, is which methods of transport are potentially most damaging? Vibration measurements were acquired for various modes of transport included manual handling and transport by trolley, van, train, ferry and commercial airliner. Probability density functions are presented for each and higher order statistics (skew and kurtosis) computed to identify near-Gaussian and non-Gaussian segments. Shock response spectra (SRS) of acceleration, pseudo-velocity and relative displacement are presented for a number of impulsive events, and corresponding vibration response spectra (VRS) shown for more normally distributed inputs. Vibration testing was carried out on an artefact packed in bespoke foam packaging inside a standard wooden transport crate. The modal response, combined with SRS and VRS, enabled the suitability of the packaging in reducing the response to different real-life stimuli to be assessed.