Key Engineering Materials Vol. 628

Abstract: This paper describes a study about the San Giacomo building for testing the dynamic identification applicability of a low-cost monitoring system, consisting of accelerometers and acquisition modules. The Stochastic Subspace Identification (SSI), a well-known technique of Operational Modal Analysis (OMA), is applied to the experimental data to evaluate the possibility of identifying the first frequencies of the building. Moreover, in order to solve the lack of synchronization of the monitoring system, an innovative method based on the phase delay of each signal is presented and used for digitally synchronizing the data.

Abstract: Architectural heritage is an important part of the history and identity of countries, but ancient buildings suffer a high vulnerability to hazards, which may induce unpredictable damages. For this purpose, the development of techniques for monitoring historic buildings and immediately alerting in case of early vulnerability assessment is a main objective to be pursued. This paper concerns with a proposal of noninvasive Neural Network-based approach for predicting risk events in artistic buildings. More in detail, a neural approach is suggested for detecting temporal novelties in images of historic evidences with the aim of monitoring early warning of risk events.

Abstract: Wireless sensor networks can be beneficial for monitoring ambient vibrations in historical buildings where the installation of traditionally wired system may be either difficult due to wiring difficulties or forbidden due to prohibitive legislation. In this paper, a novel wireless sensor network architecture is presented that is focusing on efficiently monitoring ambient vibrations in historical buildings. Traditional wired monitoring technologies are often difficult to be installed in historical buildings either to high costs for installing the wires or to prohibitive legislations. Employing a wireless system could be beneficial. However, as there is no wireless system of high resolution available in the market, an innovative network architecture is proposed that efficiently combines the benefits of both the wired and wireless systems. The problem of synchronization that this novel architecture introduces, is also discussed in this paper along with a possible solution.

Abstract: The problem of bridging the gap between the traditional wired monitoring systems and the wireless ones, was the objective of an innovative network architecture that elegantly combined benefits from both approaches. The monitoring focus is on historical buildings in which installing wires maybe range from difficult (e.g., fragile constructions) to impossible (e.g., prohibitive legislation). However, this innovative approach is vulnerable with respect to synchronization issues. In particular, all data sensed by different sensors need to have the correct universal time stamp. Since under this approach there is no central entity to take a synchronization role, in this paper the use of a local NTP server is proposed and as it is shown here using experimental results, this approach suffices for the particular monitoring needs. Thus, the claim that the innovative system can efficiently support the required monitoring of ambient vibrations in historical buildings.

Abstract: Risk prevention of historical buildings through sensor network monitoring represents a challenging and together promising task towards an optimized buildings’ protection plan. Due to the significant character that historical buildings have within the history and identity of local and consequently national communities, the monitoring approach above is nowadays considered a fundamental component of cultural preservation. Modern trends on sensor networks nowadays allow the installation of wireless monitoring equipment, able to collect a large volume and variety of data that can be further processed in order to support prevention modelling techniques and strategies. Despite the valuable post-processing outcome of the above modelling techniques, in several real-time monitoring cases, an aspect that may significant impact the data analysis accuracy from the monitoring engineer is to create an audiovisual representation of the gathered data that are easily perceived and directly associated to well-known environmental conditions. Towards this aim, in this work an audio-based representation of the collected data is introduced that achieves high monitoring performance in terms of the perceived nature of the building vibrations themselves. The proposed audio-based representation technique is based on a number of advanced sonification methods, combined with specific human-hearing simulation mechanisms that allow an effective increase of the represented information volume in real-time. A number of subjective tests that were performed demonstrate a significant improvement on the way that the monitoring personnel can efficiently perceive the origin and / or nature of the acquired vibrations, rendering the proposed technique a strong supplement towards efficient historical building risk prevention.

Abstract: In this paper a hybrid model for measurement of building vulnerability caused by strong motion arrays is proposed. Our model is based on is a multi-disciplinary method that will predict the behavior of a building structure in reaction to unforeseen stress. In addition, we classify the already proposed vulnerability assessment methods and we describe the criteria for the appropriate selection of building vulnerability assessment method.

Abstract: In this paper the model of an Innovative Monitoring Network involving properly connected nodes to develop an Information and Communication Technology (ICT) solution for preventive maintenance of historical centres from early warnings is proposed. It is well known that the protection of historical centres generally goes from a large-scale monitoring to a local one and it could be supported by a unique ICT solution. More in detail, the models of a virtually organized monitoring system could enable the implementation of automated analyses by presenting various alert levels. An adequate ICT solution tool would allow to define a monitoring network for a shared processing of data and results. Thus, a possible retrofit solution could be planned for pilot cases shared among the nodes of the network on the basis of a suitable procedure utilizing a retrofit catalogue. The final objective would consist in providing a model of an innovative tool to identify hazards, damages and possible retrofit solutions for historical centres, assuring an easy early warning support for stakeholders. The action could proactively target the needs and requirements of users, such as decision makers responsible for damage mitigation and safeguarding of cultural heritage assets.