Wireless sensor networks for heritage object deformation detection and tracking algorithm

Deformation is the direct cause of heritage object collapse. It is significant to monitor and signal the early warnings of the deformation of heritage objects. However, traditional heritage object monitoring methods only roughly monitor a simple-shaped heritage object as a whole, but cannot monitor complicated heritage objects, which may have a large number of surfaces inside and outside. Wireless sensor networks, comprising many small-sized, low-cost, low-power intelligent sensor nodes, are more useful to detect the deformation of every small part of the heritage objects. Wireless sensor networks need an effective mechanism to reduce both the communication costs and energy consumption in order to monitor the heritage objects in real time. In this paper, we provide an effective heritage object deformation detection and tracking method using wireless sensor networks (EffeHDDT). In EffeHDDT, we discover a connected core set of sensor nodes to reduce the communication cost for transmitting and collecting the data of the sensor networks. Particularly, we propose a heritage object boundary detecting and tracking mechanism. Both theoretical analysis and experimental results demonstrate that our EffeHDDT method outperforms the existing methods in terms of network traffic and the precision of the deformation detection

Damage identification in structural health monitoring: a brief review from its implementation to the Use of data-driven applications

The damage identification process provides relevant information about the current state of a structure under inspection, and it can be approached from two different points of view. The first approach uses data-driven algorithms, which are usually associated with the collection of data using sensors. Data are subsequently processed and analyzed. The second approach uses models to analyze information about the structure. In the latter case, the overall performance of the approach is associated with the accuracy of the model and the information that is used to define it. Although both approaches are widely used, data-driven algorithms are preferred in most cases because they afford the ability to analyze data acquired from sensors and to provide a real-time solution for decision making; however, these approaches involve high-performance processors due to the high computational cost. As a contribution to the researchers working with data-driven algorithms and applications, this work presents a brief review of data-driven algorithms for damage identification in structural health-monitoring applications. This review covers damage detection, localization, classification, extension, and prognosis, as well as the development of smart structures. The literature is systematically reviewed according to the natural steps of a structural health-monitoring system. This review also includes information on the types of sensors used as well as on the development of data-driven algorithms for damage identification.Peer ReviewedPostprint (published version

Multi-technique approach to rockfall monitoring in the Montserrat massif (Catalonia, NE Spain)

Montserrat Mountain is located near Barcelona in Catalonia, in the northeast of Spain, and its massif is formed by conglomerate interleaved by siltstone/sandstone with steep slopes very prone to rockfalls. The increasing number of visitors in the monastery area, reaching 2.4 million per year, has highlighted the risk derived from rockfalls for this building area and also for the terrestrial accesses, both roads and the rack railway. A risk mitigation plan has been launched, and its first phase during 2014-2016 has been focused largely on testing several monitoring techniques for their later implementation. The results of the pilot tests, performed as a development from previous sparse experiences and data, are presented together with the first insights obtained. These tests combine four monitoring techniques under different conditions of continuity in space and time domains, which are: displacement monitoring with Ground-based Synthetic Aperture Radar and characterization at slope scale, with an extremely non-uniform atmospheric phase screen due to the stepped topography and atmosphere stratification; Terrestrial Laser Scanner surveys quantifying the frequency of small or even previously unnoticed rockfalls, and monitoring rock block centimetre scale displacements; the monitoring of rock joints implemented through a wireless sensor network with an ad hoc design of ZigBee loggers developed by ICGC; and, finally, monitoring singular rock needles with Total Station.Peer ReviewedPostprint (author's final draft

Open-source digital technologies for low-cost monitoring of historical constructions

This paper shows new possibilities of using novel, open-source, low-cost platforms for the structural health monitoring of heritage structures. The objective of the study is to present an assessment of increasingly available open-source digital modeling and fabrication technologies in order to identify the suitable counterparts of the typical components of a continuous static monitoring system for a historical construction. The results of the research include a simple case-study, which is presented with low-cost, open-source, calibrated components, as well as an assessment of different alternatives for deploying basic structural health monitoring arrangements. The results of the research show the great potential of these existing technologies that may help to promote a widespread and cost-efficient monitoring of the built cultural heritage. Such scenario may contribute to the onset of commonplace digital records of historical constructions in an open-source, versatile and reliable fashion.Peer ReviewedPostprint (author's final draft

Development of a new device for the measurement and modeling of an innovative risk index for cultural heritage application

The monitoring, as a function of time, of environmental parameters in cultural heritage is essential to preserve materials, to recognize the reasons of degradation and to evaluate their effects. The degrading effects of objects in cultural heritage field, can be classified in optical, morphological, physical-chemical/mechanical and alterations and depend by micro-climatic conditions. For this reason, in recent years, several solutions have been developed and commercialized for environmental monitoring, some compatible with general advice and others OEM (Original Equipment Manufacturing). However, the trend of application between compliant and non-ISO-compliant devices has not yet been sufficiently analyzed. In this first section, we show how in the last ten years researchers have shifted their attention to custom-made devices based on new generation sensors despite the expense of units ISO certified. The study based on a review of scientific articles has shown that: with the increase of low-cost and open-source technologies applied in the Environmental Impact Assessment (EIA) and in particular in the cultural heritage, led to a research advancement in the field, but, at the same time, increased non-homogeneity of the methods, impinging comparability of results. In recent years the trend is to use low-cost automatic wireless systems. This innovation, however, opens new scenarios and challenges on how to improve their stability, longevity, and sensitivity; reduce maintenance (battery replacement, including calibration or sensors); improve data analysis/management/display costs. In particular, it has highlighted the current difficulty of low-cost detectors to satisfy the robustness and reliability of regulatory and conventional stationary monitors at the expense of the periods and aesthetics. We have therefore paid particular attention to the sensitivity and reliability of the innovative solutions presented to overcome the traditional limitations, as well as to the real feasibility of solutions regarding sustainability, adaptability to the works of art or price. We also see the need for more communication between the scientific community and the decision-makers, who have only recently opened up to this paradigm. We highlighted the need to identify recurrent or innovative topics in the various documents concerning the approaches to preventive conservation, the preservation of damage and environmental management. After a review of state of the art regarding the different sampling device applied in cultural heritage and a survey of the parameters that involve a degradation effect on the materials, in this section, we focus our attention on a sensors-based prototype able to detect: (i) temperature and relative humidity; (ii) NO, NO2 and SO2; (iii) vibrations. In particular, this section describes the design and the validation of the Wireless Sensor Network (WSN) propose3, named WENDY, an acronym for Wireless Environmental moNitoring Device prototYpe. WENDY, built on a microcontroller of ATmega328P series, gathers signals from a sensor for temperature and relative humidity; a 9-axis MIMU; and three gas detection miniature boards (NO, NO2 and SO2). Complete the board a connector for memory card (SD) and an RTC. Additionally, a module based on the ZigBee standard could be used to transmit all data. In this section, precisely, we present the performances of the WSN node in detecting: structure tilt, vibrations and the daily cycle of humidity, temperature and gas deposition. The experimental setup used to evaluate the accuracy of MIMU system highlighted a relative error on shock acceleration measurement, in term of normalized root mean square error, lower than 0.1 % for the sinusoidal input and 0.51 % for cardinal sin input, with an average accuracy in the principal peak reconstruction of 1 % in the chosen frequency range (5 Hz to 50 Hz). The MIMU accuracy for tilt measurement, evaluated through the root mean square error was equal to 0.3° and a standard deviation always lower than 0.4° in the 0-90° tilt range. The gas detection and temperature/ humidity boards showed data comparable with the nearby certified ARPA system device. The aim of the applicative section is monitoring effects of different factors which affect the “Minerva Medica Temple,” an archeological site in Rome. In particular, we focus on: (i) the seasonal thermal variations on the structure; (ii) the contamination due to by local traffic regarding gaseous pollutant and (iii) the dynamic response of the structure to a tramway line located in Rome and called “Roma- Giardinetti.” The developed system allows for prioritization of intervention both for management and interventions planning, regarding restoration, consolidation, and conservation. Moreover, the software structure of the environmental monitoring device is presented and expounded in detail.4 Always in this section, an innovative procedure for the evaluation of the environmental hazard in cultural heritage is proposed. This risk assessment can be considered as a “relative risk assessment methodology.” In particular, it considers the impacts of microclimatic conditions on the monument, based on the international norms and the current scientific knowledge. For measurement campaigns with WENDY, the risk method proposed is applied to the results of two measurement campaigns carried out between 2017 and 2018 over two different periods (September-December and March-July), at “Minerva Medica Temple,” in Rome

D5.1 SHM digital twin requirements for residential, industrial buildings and bridges

This deliverable presents a report of the needs for structural control on buildings (initial imperfections, deflections at service, stability, rheology) and on bridges (vibrations, modal shapes, deflections, stresses) based on state-of-the-art image-based and sensor-based techniques. To this end, the deliverable identifies and describes strategies that encompass state-of-the-art instrumentation and control for infrastructures (SHM technologies).Objectius de Desenvolupament Sostenible::8 - Treball Decent i Creixement EconòmicObjectius de Desenvolupament Sostenible::9 - Indústria, Innovació i InfraestructuraPreprin

System Identification of Constructed Facilities: Challenges and Opportunities Across Hazards

The motivation, success and prevalence of full-scale monitoring of constructed buildings vary considerably across the hazard of concern (earthquakes, strong winds, etc.), due in part to various fiscal and life safety motivators. Yet while the challenges of successful deployment and operation of large-scale monitoring initiatives are significant, they are perhaps dwarfed by the challenges of data management, interrogation and ultimately system identification. Practical constraints on everything from sensor density to the availability of measured input has driven the development of a wide array of system identification and damage detection techniques, which in many cases become hazard-specific. In this study, the authors share their experiences in fullscale monitoring of buildings across hazards and the associated challenges of system identification. The study will conclude with a brief agenda for next generation research in the area of system identification of constructed facilities

Monitoring and Self-diagnosis of Civil Engineering Structures: Classical and Innovative Applications

Eventi estremi come esplosioni o terremoti possono avere un profondo impatto nella sicurezza degli edifici. Le zone sismiche devono convivere con questi tragici eventi, per questo monitorare in maniera continua le condizioni di salute di una struttura è necessario e auspicabile in molti casi. Il monitoraggio strutturale (Structural Health Monitoring – SHM) rappresenta un potente strumento per la valutazione del comportamento dinamico della struttura monitorata. Fino a pochi anni fa queste tecniche erano impiegate prevalentemente in ambito meccanico, aeronautico e nell’ingegneria aerospaziale. Al giorno d’oggi, la riduzione dei costi della strumentazione, sistemi di acquisizione dati di nuova generazione e l’incremento continuo dell’efficienta nelle analisi numeriche hanno reso possibile l’applicazione di queste tecniche anche a strutture civili ordinarie. Le tecniche di monitoraggio strutturale vengono applicate non solo in grandi infrastrutture come ponti, dighe o grattacieli, ma anche in strutture storiche o edifici residenziali. In questo contesto questa tesi tenta di esaminare differenti aspetti del monitoraggio strutturale, in particolar modo riferite a edifici ordinari. Attraverso tecniche Output-Only (Operational Modal Analysis – OMA) sono state monitorate diverse strutture civili con reti di sensori cablate, al fine di ottenere il comportamento dinamico strutturale nelle reali condizioni opertive. Particolare attenzione è stata focalizzata in un altra importante tematica dell’ingegneria strutturale: il danneggiamento strutturale. Attraverso un approccio numerico viene presentato un nuovo metodo per la localizzazione e quantificazione del danno a seguito di un evento sismico. In alternativa alla classica rete cablata, è stato sviluppato un sistema di acquisizione con sensori wireless (Wireless Sensor Network – WSN). I principali risultati ottenuti con questa applicazione vengono riportati nella presente tesi, unitamente al design dei sensori low-cost. Con l’ausilio della sensoristica sviluppata è stato monitorato un edificio storico in muratura, mostrando i risultati positivi ottenuti a seguito della campagna di acquisizione di rumore ambientale (Ambient Vibration Survey -AVS).Extreme events like explosions and earthquakes may have a deep impact on building safety. Seismic regions must live with these tragic events, so that continuous monitoring of structure health conditions is necessary in many cases. Structural Health Monitoring (SHM) represents a powerful tool for the evaluation of dynamic behavior of monitored structures. Until a few years ago these techniques were widely employed especially in mechanical, aeronautical and aerospace engineering. Nowadays, the reduction of equipment costs, the new generation of data acquisition systems, together with the continuous improvement of computational analysis have made it possible to apply SHM also to civil structures without strategic importance. SHM has moved from large infrastructures like bridges, dams and skyscrapers to historical heritage and residential buildings. In this background, the present work tries to examine different aspects of SHM applications, especially referred to ordinary buildings. Using Operational Modal Analysis (OMA) techniques, several civil structures have been monitored through a wired network sensor, in order to obtain the dynamic behavior in operating conditions. The relevant data collection provides a useful tool for calibrating the accuracy and sensitivity of similar SHM case studies. Specific attention is focused in another important issue in civil and in mechanical engineering: detection of structural damages. Through a numerical approach, a new method for damage localization and quantification is proposed. Besides the traditional wired acquisition system a Wireless Sensor Network (WSN) has been developed. The issues related to the usage of low-cost sensors and new generation data acquisition tools for non-destructive structural testing are discussed. Using the WSN an historical masonry building has been monitored, showing the positive results obtained following the Ambient Vibration Survey (AVS)

Vision-based vibration monitoring of structures and infrastructures: overview of recent applications

Contactless structural monitoring has in recent years seen a growing number of applications in civil engineering. Indeed, the elimination of physical installations of sensors is very attractive, especially for structures that might not be easily or safely accessible, yet requiring the experimental evaluation of their conditions, for example following extreme events such as strong earthquakes, explosions, and floods. Among contactless technologies, vision-based monitoring is possibly the solution that has attracted most of the interest of civil engineers, given that the advantages of contactless monitoring can be potentially obtained thorough simple and low-cost consumer-grade instrumentations. The objective of this review article is to provide an introductory discussion of the latest applications of vision-based vibration monitoring of structures and infrastructures through an overview of the results achieved in full-scale field tests, as documented in the published technical literature. In this way, engineers new to vision-based monitoring and stakeholders interested in the possibilities of contactless monitoring in civil engineering could have an outline of up-to-date achievements to support a first evaluation of the feasibility and convenience for future monitoring tasks