Advanced Video-Based Processing for Low-Cost Damage Assessment of Buildings under Seismic Loading in Shaking Table Tests

This paper explores the potential of a low-cost, advanced video-based technique for the assessment of structural damage to buildings caused by seismic loading. A low-cost, high-speed video camera was utilized for the motion magnification processing of footage of a two-story reinforcedconcrete frame building subjected to shaking table tests. The damage after seismic loading was estimated by analyzing the dynamic behavior (i.e., modal parameters) and the structural deformations of the building in magnified videos. The results using the motion magnification procedure were compared for validation of the method of the damage assessment obtained through analyses of conventional accelerometric sensors and high-precision optical markers tracked using a passive 3D motion capture system. In addition, 3D laser scanning to obtain an accurate survey of the building geometry before and after the seismic tests was carried out. In particular, accelerometric recordings were also processed and analyzed using several stationary and nonstationary signal processing techniques with the aim of analyzing the linear behavior of the undamaged structure and the nonlinear structural behavior during damaging shaking table tests. The proposed procedure based on the analysis of magnified videos provided an accurate estimate of the main modal frequency and the damage location through the analysis of the modal shapes, which were confirmed using advanced analyses of the accelerometric data. Consequently, the main novelty of the study was the highlighting of a simple procedure with high potential for the extraction and analysis of modal parameters, with a special focus on the analysis of the modal shape’s curvature, which provides accurate information on the location of the damage in a structure, while using a noncontact and low-cost method

Integration of Non-Destructive Acoustic Imaging Investigation with Photogrammetric and Morphological Analysis to Study the “<i>Graecia Vetus</i>” in the Chigi Palace of Ariccia

Integrating complementary information from many available technologies is a question of growing interest among the Cultural Heritage community, due to the complexity of the cultural assets under study and of their contexts. Recently, this need has pushed the development of appropriate data fusion procedures for this sector, among which the authors wish to propose their approach for treating multi-source data from image-based methodologies, experimented with in a representative case study. The Chigi Palace of Ariccia hosted our investigation campaign on a precious monochrome painting by Giuseppe Cades (1788), the Graecia Vetus. The study encompasses a photogrammetric survey and two acoustic diagnostic methods, the innovative Frequency Resolved Acoustic Imaging technique and the more traditional Acoustic Tomography. The photogrammetric survey allows reconstruction of the surface morphology of the painting, generating a 3D Digital Elevation Model, while the acoustic methods detect the structural damage beneath the surface due to detachments and flaws, generating 2D images. The output of this heterogeneous datasets fusion is a multi-layer map, each layer representing a type of dataset that clearly shows how some deformations of the surface morphology appear correlated with the presence of sub-surface anomalies, wide air cavities and more superficial detachments revealed by the acoustic diagnostic methods. Beside the exam of the conservation state of the Graecia Vetus, the proposed procedure effectively guarantees access to the integrated information, offering the possibility to understand the correlation between the causes and the effects of the decay process, as well as the retrieval of the single analysis in order to deepen one specific aspect

Sperimentazione dell’ENEA condivisa in remoto per la diffusione di tecnologie innovative di protezione antisismica

Abstract Within the framework of the CO.B.R.A. project for the development and dissemination of methods, technologies and advanced tools for the conservation of cultural heritage, data and experimental results of several shaking table tests were remotely shared. Through the upgrading of the laboratory with new optoelectronic instrumentation and the application of innovative video processing techniques, the vibrations induced to two typical Italian historic masonry walls and to an isolated pedestal provided with early-warning system for delicate statues were measured and analyzed

Impact of traffic vibration on the temple of Minerva Medica, Rome: preliminary study within the Co.B.Ra. project

The impact of long-term traffic vibration on ancient structures located in the city centre of big cities is an important issue, as it represents the main factor of fatigue, possibly causing structural damage in historic constructions. This article illustrates the preliminary results of a study on the so-called Temple of Minerva Medica in Rome, Italy, conducted within the CO.B.RA. project, which focuses on the development of advanced technologies and methods for the conservation of cultural heritage assets. The studied monument, which is part of the architectural heritage of ancient Rome, is located very close to several railway tracks just out of the Termini train station, on the north-east side, and to urban tramways, on the west side. To obtain indications on the dynamic behaviour of the structure and to map the base excitation induced by passing trains and trams, ambient vibration data were acquired by digital recorders with triaxial velocimeters positioned at several measurement points on the ground, around and inside the structure, and at different heights on the north-west façade. For evaluating the structural vulnerability, three-dimensional (3D) architectural surveys and non-destructive investigations on the material properties of the monument were conducted in order to implement a finite element model of the building to be used for structural analyses and dynamic simulations. In particular, to the purpose of obtaining a detailed 3D model, laser scanner and stereo-photogrammetric acquisitions were carried out. Photographic acquisitions were also used to identify the crack pattern and to document the current state of damage. Vibration and 3D reconstruction data were acquired both in summer and in winter, along with thermographic images, for assessing the seasonal effects on the structural behaviour. All collected data were stored into an ad hoc friendly data repository accessible through the internet by the accredited project end-users

Moisture Damage in Ancient Masonry: A Multidisciplinary Approach for In Situ Diagnostics

San Nicola in Carcere, one of the minor basilicas in the historical center of Rome, was the location of a wide investigation campaign of the water-related deterioration causes, present in the lower sector of the apse and adjacent pillars, affected by water infiltrations, mould and salt efflorescence. The results obtained identify the presence of water content and related effects mainly on the sides of the apsidal wall. This work focuses on the use of five Non-Destructive Techniques (NDT) and intends to show the gains obtained by integrating widely interdisciplinary methods, namely the Infrared Thermography (IRT), the Unilateral Nuclear Magnetic Resonance (Unilateral NMR), the Acoustic Tomography (AT), the Acoustic Imaging (AI) and the Laser-Induced Fluorescence (LIF). All the techniques contribute to the rapid, non-invasive and early identification of the moisture distribution, while some of them (LIF and AI) also address the determination of some moisture effects. The integrated use of different techniques helps to take the multidisciplinary point of view necessary to formulate an effective restoration intervention based on a sound scientific rationale; nonetheless, it allows to experiment a holistic approach, verifying the potential of a wide range of NDTs available within the context of a restoration yard