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This review examines the integration of advanced ultrasonic techniques and artificial intelligence (AI) for monitoring and analyzing concrete structures, focusing on detecting and classifying internal defects. Concrete structures are subject to damage over time due to environmental factors and dynamic loads, compromising their integrity. Non-destructive techniques, such as ultrasonics, allow for identifying discontinuities and microcracks without altering structural functionality. This review addresses key scientific challenges, such as the complexity of managing the large volumes of data generated by high-resolution inspections and the importance of non-linear models, such as the Hammerstein model, for interpreting ultrasonic signals. Integrating AI with advanced analytical models enhances early defect diagnosis and enables the creation of detailed maps of internal discontinuities. Results reported in the literature show significant improvements in diagnostic sensitivity (up to 30% compared to traditional linear techniques), accuracy in defect localization (improvements of 25%), and reductions in predictive maintenance costs by 20–40%, thanks to advanced systems based on convolutional neural networks and fuzzy logic. These innovative approaches contribute to the sustainability and safety of infrastructure, with significant implications for monitoring and maintaining the built environment. The scientific significance of this review lies in offering a systematic overview of emerging technologies and their application to concrete structures, providing tools to address challenges related to infrastructure degradation and contributing to advancements in composite sciences. [ABSTRACT FROM AUTHOR]

Arrangements of piezoelectric transducers, such as PZT (lead zirconate titanate), have been widely used in numerous structural health monitoring (SHM) applications. Usually, when two or more PZT transducers are placed close together, significant interference, namely crosstalk, appears. Such an effect is usually neglected in most SHM applications. However, it can potentially be used as a sensitive parameter to identify structural faults. Accordingly, this work proposes using the crosstalk effect in an arrangement of PZT transducers modeled as a multiconductor transmission line to detect structural damage. This effect is exploited by computing an impedance matrix representing a host structure with PZTs attached to it. The proposed method was assessed in an aluminum beam structure with two PZTs attached to it using finite element modeling in OnScale® software to simulate both healthy and damaged conditions. Similarly, experimental tests were also carried out. The results, when compared to those obtained using a traditional electromechanical impedance (EMI) method, prove that the new approach significantly improved the sensitivity of EMI-based technique in SHM applications. [ABSTRACT FROM AUTHOR]

Mitigating seismic risk for critical facilities is crucial for governments, decision-makers, researchers, society, and the economy in earthquake-prone regions in Europe and worldwide. The paper discusses some essential concepts and methods for developing and implementing a real-time risk assessment methodology through a specific testbed example in light of an engineering-based seismic risk reduction approach for critical buildings. The goal is to demonstrate that real-time seismic risk assessment of a target building could be feasible by combining a calibrated earthquake early warning system (EEWS) with the knowledge of structure-specific fragility curves evaluated with the aid of well-designed structural monitoring arrays. The whole approach is illustrated for a school building located in Thessaloniki city center. The target school is instrumented with permanent and temporary monitoring arrays using commercial accelerometric/velocimeter stations and special in-house developed low-cost Micro-Electro-Mechanical Systems (MEMS). Structural health monitoring (SHM) allows identifying the dynamic characteristics of the building and, finally, generate structure-specific fragility functions, which may differ from generic ones. Past and current seismic events recorded on the regional seismic network and locally on sensors installed at the school building are used for the calibration and validation of the regional EEWS in order to reduce the rate of false or missed alarms. The refined structure-specific fragility functions are incorporated into the central database and used by the developed real-time risk assessment software for the promptly prediction of seismic damages and losses. The performance of the whole system is effectively checked for a strong seismic event by reproducing the Mw 6.5, 1978 Thessaloniki destructive earthquake based on 3D physics-based numerical simulations. [ABSTRACT FROM AUTHOR]

This study develops a structural stability monitoring method for an implant structure (i.e., a single-tooth dental implant) through deep learning of local vibrational modes. Firstly, the local vibrations of the implant structure are identified from the conductance spectrum, achieved by driving the structure using a piezoelectric transducer within a pre-defined high-frequency band. Secondly, deep learning models based on a convolutional neural network (CNN) are designed to process the obtained conductance data of local vibrational modes. Thirdly, the CNN models are trained to autonomously extract optimal vibration features for structural stability assessment of the implant structure. We employ a validated predictive 3D numerical modeling approach to demonstrate the feasibility of the proposed approach. The proposed method achieved promising results for predicting material loss surrounding the implant, with the best CNN model demonstrating training and testing errors of 3.7% and 4.0%, respectively. The implementation of deep learning allows optimal feature extraction in a lower frequency band, facilitating the use of low-cost active sensing devices. This research introduces a novel approach for assessing the implant's stability, offering promise for developing future radiation-free stability assessment tools. [ABSTRACT FROM AUTHOR]

Computer vision enables a much more efficient monitoring system of structural behavior, compared to traditional methods. This derives from the fact that it allows the assessment of displacements in a vast number of points that can be processed to the estimate deformations, accelerations, and other key parameters at relevant cross‐sections. This paper proposes a computer vision‐based methodology, specifically designed for monitoring seismic tests conducted on a shaking table with a reduced‐scale model, using a single camera approach. This innovative methodology uses artificial targets with predefined color and geometry to optimize their detection and tracking. These targets are positioned at key points of the reduced model—“Moving Targets”—and at reference points of the seismic table—“Control Targets.” Videos are recorded during the seismic tests and the coordinates (in pixels) of the targets' centers are automatically detected and captured. Then, transformations are applied to each frame to compute the targets coordinates in millimeters and based on the differences between frames, to calculate the displacements of each target. The methodology was first calibrated with dynamic tests performed on a reduced‐scale model (1:33) of a prefabricated concrete shell, printed in acrylonitrile butadiene styrene (ABS), conducted on an educational shaking table. Afterwards, the methodology was validated with seismic tests performed on a 1:3 reduced model of a prefabricated concrete shell, produced according to the similitude theory to best reproduce the behavior of the corresponding prototype. It was demonstrated the ability of the methodology to monitoring seismic tests, enabling continuous tracking of the targets placed on a structure with complex geometry. [ABSTRACT FROM AUTHOR]

The box girder's condition significantly impacts the safety and overall performance of the entire ship because it is the primary stress component of the hull construction. This work used experimental research on the long-span hull box girder based on IFEM (Inverse Finite Element Method) technology to ensure the structural safety of the hull box girder. Due to the limitations of conventional experiments in this technical field, such as their reliance on finite element data and lack of input from physical tests, numerous research methods combining the strain sensing data from physical tests with the strain data from virtual sensors were conducted. The strain fields of the top plate, side plate, and bottom plate were each reconstructed in turn, and the verifier measuring points in the physical model test were used to assess the accuracy of the reconstruction results. The findings demonstrate that the top plate, side plate, and bottom plate reconstructions had relative errors of 0.24–7.86%, 0.75–8.13%, and 3.31–2.52%, respectively. This enables the reconstruction of the strain field of the long-span hull box girder using physical test data and promotes the use of iFEM technology in the field of structural health monitoring of large marine structures. [ABSTRACT FROM AUTHOR]

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Thanks to the capabilities of distributed fibre optic sensors (DFOS), a significant increase in their applications within civil and geotechnical engineering has been observed during the last few years. In contrast to conventional spot gauges, the main advantage of this technology is direct damage detection, as the information is gained over the entire measurement path. This diagnostic solution is especially suitable for safety-critical infrastructure, including bridges. However, to utilise the benefits of the DFOS approach, appropriate interrogators, sensors, and installation methods must be adopted. The article briefly discusses possible solutions available on the market, indicating their specific advantages and limitations. Then, several practical case studies related to bridge monitoring in Poland are presented. The review shows various possible applications, from long measurement sections over entire spans to small-size structural components. Some are truly new and pioneer solutions, solving different technical problems in bridge engineering. Presented applications supported by in situ data proved the possible high-quality performance of DFOS-based systems for measurements of concrete, steel and composite bridges in actual operating conditions. [ABSTRACT FROM AUTHOR]

This paper proposes an electromechanical impedance measurement (EIM)-based solution for monitoring concrete maturity that refers to concrete strength development at the early stage. A smart aggregate (SMA) that consists of a waterproofed piezoelectric patch is developed. The working principle is explained based on the impedance theory of an electromechanically coupled system. A finite element (FE) model of the EIM-SMA unit is established. The stiffness of the applied spring foundation is varied to emulate the concrete hardening process. The simulation results reveal that a peak located between 60 and 70 kHz in the impedance plot could be used as an indication to reflect the stiffness variation of the spring foundation. A 3D-printed mold is designed for rapid production of the EIM-SMA units. In the experiment, two sample EIM-SMA units are used to monitor fresh concrete maturity in the first 6 h after casting. The results of the two sample EIM-SMA units agreed well. The experimental results matched the simulation prediction. Compared to a bar-dropping test that is widely adopted at construction sites, the impedance evolution of an EIM-SMA unit is much smoother and has better monotonicity. In general, the proposed method has been proven to be a reliable solution to monitor the maturity development of concrete. [ABSTRACT FROM AUTHOR]

Arrangements of piezoelectric transducers, such as PZT (lead zirconate titanate), have been widely used in numerous structural health monitoring (SHM) applications. Usually, when two or more PZT transducers are placed close together, significant interference, namely crosstalk, appears. Such an effect is usually neglected in most SHM applications. However, it can potentially be used as a sensitive parameter to identify structural faults. Accordingly, this work proposes using the crosstalk effect in an arrangement of PZT transducers modeled as a multiconductor transmission line to detect structural damage. This effect is exploited by computing an impedance matrix representing a host structure with PZTs attached to it. The proposed method was assessed in an aluminum beam structure with two PZTs attached to it using finite element modeling in OnScale® software to simulate both healthy and damaged conditions. Similarly, experimental tests were also carried out. The results, when compared to those obtained using a traditional electromechanical impedance (EMI) method, prove that the new approach significantly improved the sensitivity of EMI-based technique in SHM applications.

This paper reports a novel investigation in applying commercial Ultra High-Frequency RFID tags (UHF-RFID tags), which are widely used in logistics as sensing elements in civil engineering structures, particularly for monitoring out-of-plane displacements of brick masonry walls. Both laboratory tests and in situ experimental tests assessed the feasibility of the proposed application. Laboratory tests showed a very satisfactory response while the in situ experiments showed a weaker response. Nevertheless, the potential reliability of the proposed technique can be stated. The authors traced back the causes of the performance decrease to environmental interference, mainly due to the extensive presence of a rigid steel frame surrounding the out-of-plane loaded panels. Measurements of displacements, in fact, are obtained indirectly from the phase of UHF-RFID signals that strongly suffer from multipath generated by metallic surfaces. Despite some limitations, the proposed measurement technique permits a reliable and sustainable approach to the monitoring of structures. The use of commercial UHF-RFID wireless tags, in fact, assures easy and fast installation operations and assures the possibility of placing a large number of sensors over the structure with very low maintenance costs with respect to the more traditional monitoring techniques. Moreover, using very thin and small commercial UHR-RFID tags on cultural heritage structures can represent an opportunity for sustainable long-time monitoring with reduced costs. Overall, the results of this study are sufficiently satisfactory to be considered as the opening of new possible scenarios in wireless structural monitoring in the civil engineering field. The authors propose as future work to use UHF-RFID tags for the real-time monitoring of an existing masonry facade that, not being characterized by the presence of a steel frame, can potentially assure an adequate response and properly transmit the electromagnetic signal. [ABSTRACT FROM AUTHOR]

Vibration analysis is commonly used to assess machinery conditions, earthquake detection, and structural monitoring. Commercially available DAQs (Data Acquisition Systems) feature high costs and limited versatility in terms of end-user hardware/firmware customization, making it difficult to adapt them to the input signal features and add supplementary functionalities. Hence, this research aims to develop a custom acquisition board for detecting vibration signals via IEPE (Integrated Electronic Piezoelectric) sensors, considering the limitations of commercially available systems, and building upon solutions found in the literature. The DAQ board was intended for remote vibration monitoring of infrastructure and machinery for industrial applications, allowing the implementation of predictive maintenance strategies. The proposed DAQ board has two independent and fully configurable channels, which can be set for acquiring signals from IEPE sensors or generic voltage sources. The DAQ board relies on the STM32F401 microcontroller to manage the acquisition from high-speed ADCs, process data, and store them in mass memory (SD card). During acquisition, the DAQ implements a batch acquisition strategy based on a buffer flash memory for temporarily storing ADCs data, which are iteratively poured into mass memory. Also, the board has Bluetooth connectivity to transmit acquired data and receive commands remotely. A prototype of the DAQ board was developed and tested with several waveforms, including vibration signals. The tests showed that the board can acquire vibration signals and compute the FFT onboard. The DAQ demonstrated a good balance between performance, accuracy, flexibility, and cost, making it suitable for several industrial applications and allowing for scalability and integration potential. [ABSTRACT FROM AUTHOR]

The seismic analysis of historical and monumental masonry buildings, especially churches and cathedrals, is challenging and expensive. These difficulties are mainly related to complex geometry and the mechanical modelling of historic masonry structures. This paper aims to show the methodological approach to evaluate the seismic vulnerability of Masonry Cathedrals by modelling seismic analysis. The numerical finite element model, modelled with solid elements, was optimised based on identifying the primary dynamic properties performed in ambient and seismic excitations recorded by a continuous dynamic monitoring system in operation since 2015. We carried out linear dynamic analyses for the optimised model of the entire structure. We also carried out non-linear dynamic analyses for the vaults, where damage concentrations were detected after various seismic events. The linear dynamic analysis of the optimised entire structural model aimed to estimate the time histories of acceleration at the connection areas between the vaults to the vertical structures. The numerical analysis results were consistent with the damage maps identified for the actual structure. Furthermore, the numerical model and the analysis procedure showed an excellent ability to reproduce the accurate structural response. [ABSTRACT FROM AUTHOR]

Background. As of today in Russia there are no scientific-technical and experimental-technological reserves on development of systems of structural monitoring of serviceability of products and objects of rocket-space technology (RST) and ground space infrastructure (GSI) with transducers of physical quantities on the basis of macrofiber actuators on the basis of inverse piezo effect necessary for full assessment of reliability of technically complex objects by non-destructive methods. The development of the latest generation of aerospace structures requires the creation of advanced materials that would have high physical and mechanical parameters, meet reliability and durability requirements for specific tasks. Great importance is also given to active materials and structures capable of forming functional shapes and profiles depending on the external influence, i.e. to ensure the fulfillment of one of the principles of the motion control concept – adaptronics. The formation of functional shapes and profiles will provide optimal wing aerodynamic profile, better maneuverability of the aircraft, reduce fuel, energy consumption and provide better remote control in extreme space conditions. The purpose of this article is to create a scientific-technical and experimental-technological reserve for the development of advanced technologies for the production of sensor and actuator elements of structural performance monitoring systems based on piezoceramic materials and technologies for incorporation into the elements of composite structures of RST and GSI products in order to control and manage their characteristics to prevent emergencies. Materials and methods. The paper considers the structure of the system of structural monitoring of serviceability of products and objects of RST and GSI with transducers of physical quantities on the basis of macrofiber actuators based on the inverse piezo effect. Results. As a result of technology implementation, import-independent self-regulating adaptive structures of spacecraft structures and equipment will be created on the basis of controllable properties of materials with response to external influences. Implementation of the technology will make it possible to create an effective system for controlling vibrations of structural elements. The developed piezoactuators will find applications in structural monitoring systems of the aerospace industry in rocket and space technologies and mechanical engineering.

This study investigates the dynamic responses of the Davutpaşa Pedestrian Bridge to pedestrian loads using low-cost and high-cost Global Navigation Satellite Systems (GNSS) along with accelerometers. Traditionally, expensive dual-frequency GNSS receivers were employed for structural monitoring, but recent advancements in low-cost GNSS technology have provided a cost-effective alternative. The study employs signal filtering techniques and Fast Fourier Transform (FFT) to analyse datasets in time and frequency domains. Specifically, the Yule-Walker Design of Infinite Impulse Response (IIR) Band-pass Filter is applied to GNSS measurements to reveal natural frequencies obscured by noise. The accuracy was assessed by comparing frequency values obtained through full-scale monitoring with those from a Finite Element (FE) model. After filtering analysis, it has been determined that the natural frequencies obtained from geodetic GNSS agree with accelerometer frequencies with a maximum difference of 0.12 Hz (3%). In low-cost GNSS receivers, for the A10 antenna, a maximum difference of 0.09 Hz (3%), and for the UBX antenna, a maximum difference of 0.10 Hz (3%) has been obtained, showing compatibility with the accelerometer. As a result, it has been found that with appropriate filtering techniques and selecting sampling intervals suitable for structural dynamics, even rigid structures like pedestrian bridges can have their natural frequencies determined using geodetic equipment.

A great deal of signals coming from structural monitoring scenarios are sparse in the frequency domain, suggesting the application of Compressive Sensing (CS) techniques in order to reduce the quantity of transmitted information. CS can recover data vectors starting from a subset of the original vector entries, thus allowing to recover a previously sampled signal with much less samples than those suggested by the Nyquist-Shannon theorem, and much less than what is commonly used in dynamic identification of structures. A CS technique, specifically Basis Pursuit, is applied for the dynamic identification study of a 30-meter-high lightning rod, consisting of a steel monotubular pole, where possible issues had been raised concerning fatigue damage due to resonant response with the first and second modes of vibration. An experimental measurement campaign was carried out to estimate damping coefficients useful for structural verifications. The ambient response was collected using triaxial accelerometers positioned at the top and at an intermediate height, which transmit data via WiFi to a nearby workstation. Different sampling frequencies for the compressed records are utilized for the dynamic identification of the structure, comparing modal frequencies and damping ratios with values obtained from the original records to find the best trade-off between data reduction and accuracy of modal parameters. Despite the usual challenges inherent in identification problems, further complicated by the low damping levels of the structure under consideration, the comparisons demonstrate a very good approximation. Fundamental frequencies are accurately estimated, while the slight discrepancies in the damping coefficients are associated with the intrinsic uncertainties of this parameter. Regarding the structural aspect of the case study, the outcomes of the analysis indicate very low damping values, pointing to potential criticality, particularly in the second mode of vibration. Moreover, the solid approximation achieved with the CS technique marks a significant advancement in applying IoT solutions for structural monitoring, emphasizing a significant reduction in data flow without affecting data quality. This may lead to several benefits, including simpler installation and maintenance, lower costs, and decreased energy consumption.

This study develops a structural stability monitoring method for an implant structure (i.e., a single-tooth dental implant) through deep learning of local vibrational modes. Firstly, the local vibrations of the implant structure are identified from the conductance spectrum, achieved by driving the structure using a piezoelectric transducer within a pre-defined high-frequency band. Secondly, deep learning models based on a convolutional neural network (CNN) are designed to process the obtained conductance data of local vibrational modes. Thirdly, the CNN models are trained to autonomously extract optimal vibration features for structural stability assessment of the implant structure. We employ a validated predictive 3D numerical modeling approach to demonstrate the feasibility of the proposed approach. The proposed method achieved promising results for predicting material loss surrounding the implant, with the best CNN model demonstrating training and testing errors of 3.7% and 4.0%, respectively. The implementation of deep learning allows optimal feature extraction in a lower frequency band, facilitating the use of low-cost active sensing devices. This research introduces a novel approach for assessing the implant’s stability, offering promise for developing future radiation-free stability assessment tools.

The box girder’s condition significantly impacts the safety and overall performance of the entire ship because it is the primary stress component of the hull construction. This work used experimental research on the long-span hull box girder based on IFEM (Inverse Finite Element Method) technology to ensure the structural safety of the hull box girder. Due to the limitations of conventional experiments in this technical field, such as their reliance on finite element data and lack of input from physical tests, numerous research methods combining the strain sensing data from physical tests with the strain data from virtual sensors were conducted. The strain fields of the top plate, side plate, and bottom plate were each reconstructed in turn, and the verifier measuring points in the physical model test were used to assess the accuracy of the reconstruction results. The findings demonstrate that the top plate, side plate, and bottom plate reconstructions had relative errors of 0.24–7.86%, 0.75–8.13%, and 3.31–2.52%, respectively. This enables the reconstruction of the strain field of the long-span hull box girder using physical test data and promotes the use of iFEM technology in the field of structural health monitoring of large marine structures.

Ports play a significant role in the economic and social activities of the areas they serve. However, the adverse effects of the harsh and highly corrosive environments that ports operate in, along with phenomena related to the climate crisis and insufficient maintenance practices, increase port infrastructure's susceptibility to rapid degradation. This degradation can be aesthetic, functional, or structural and often leads to loss of serviceability at either a component (local and national) level or a global level. Moreover, many port structures have reached the limit of their lifetime, thus introducing the concept of extending their lifespan as a financially attractive alternative to constructing new facilities. Therefore, port operators pursue monitoring the structural integrity of the structures through an inspection plan aiming to reduce their maintenance and rehabilitation costs and ensure the safety of both the port infrastructure itself and human lives. Optimising monitoring approaches to enable damage detection and condition assessment can be achieved through the employment of Non-Destructive Testing (NDT) and Remote Sensing (RS) techniques. The current surge of using Unmanned Aerial Vehicles (UAVs) for both RS and NDT monitoring practices has proved promising since UAVs provide improved accessibility, increased inspection speed, and reduced safety hazards. The present paper is focused on investigating and evaluating the recent advances in UAV-driven port infrastructure monitoring. For this purpose, a comprehensive review of UAVs applications combined with NDT Infrared Thermography (IRT) and Ground Penetrating Radar (GPR) or RS Close Range Photogrammetry (CRP) and Light Detection and Ranging (LiDAR) is carried out to assess the potential and the limitations of the UAV-based monitoring approaches. This research provides valuable information on enhancing management strategies by upgrading port monitoring practices.

Ancient masonry constructions and historical buildings, such as cathedrals, are exposed to considerable risks attributed to factors like ageing and long-term exposure to both dynamic and static variations in loading conditions. In this study, an innovative and promising monitoring approach was applied to assess the structural integrity of the vault in the central nave of the Turin Cathedral. Specifically, the outcomes obtained from Acoustic Emissions (AE) are correlated with the insights derived from the Thrust Network Analysis (TNA) conducted on the structure. This analysis considers the structural elements introduced early in the twentieth century to mitigate horizontal forces. Acoustic Emission (AE) is a commonly employed technique in structural monitoring to detect and analyze elastic waves generated by crack formation, providing valuable information about structural damage. The Thrust Network Analysis (TNA) is an approach that applies Heyman's principles to represent stress in masonry vaults. This method models the stresses as a discrete network of forces, achieving equilibrium with gravitational loads. In this context, the results obtained by TNA analysis are strictly correlated with AE localization results.

Digital image correlation (DIC) is an optical technique used to measure surface displacements and strains in materials and structures. This technique has demonstrated significant utility in structural examination and monitoring. This manuscript offers a comprehensive review of the contemporary research and applications that have leveraged the DIC technique in laboratory-based structural tests. The reviewed works encompass a broad spectrum of structural components, such as concrete beams, columns, pillars, masonry walls, infills, composite materials, structural joints, steel beams, slabs, and other structural elements. These investigations have underscored the efficacy of DIC as a metrological instrument for the precise quantification of surface deformation and strain in these structural components. Moreover, the constraints of the DIC technique have been highlighted, especially in scenarios involving extensive or complex test configurations. Notwithstanding these constraints, the effectiveness of the DIC methodology has been validated as a strain measurement instrument, offering numerous benefits such as non-invasive operation, full-field measurement capability, high precision, real-time surveillance, and compatibility with integration into other measurement instruments and methodologies. [ABSTRACT FROM AUTHOR]

The prediction of the structural behavior and the internal forces acting in segmental tunnel linings is a difficult task and contains uncertainties. In situ measurements within structural monitoring are the only possibility to assess the results under realistic boundary conditions. However, no standardized structural monitoring method for segmented lining exists and consequentially setting up a new monitoring project requires an increased effort. Therefore, in this paper, first, an analysis of experiences in reported monitoring projects is done. Then, a report on a current monitoring project carried out by the authors and the experiences made are presented. Based on these, suggestions are given to facilitate future applications of structural monitoring on segmental tunnel linings regarding conceptualization, instrumentation, installation, operation, and data evaluation. [ABSTRACT FROM AUTHOR]

Structural monitoring strategies contributing to a realistic assessment and surveillance of engineering structures – experiences from research and practice Structural monitoring allows for capturing the actual load‐bearing behavior of engineering structures and their realistic assessment and surveillance. Various technical and organizational aspects must be considered for a successful application of structural monitoring. These include the preparation and conceptual design of the monitoring, the calibration and validation of the measurements, the installation and operation of the measurement system, as well as the data evaluation and analysis. These aspects will be discussed based on experiences from research and practice, and consequential recommendations will be given. The application possibilities of structural monitoring are presented with four examples. [ABSTRACT FROM AUTHOR]

Modern infrastructure heavily relies on robust concrete structures, underscoring the critical need for effective monitoring to ensure their safety and durability. This paper addresses this imperative issue by introducing an innovative automated and wireless system for continuous structural monitoring. By employing embedded electrical resistivity sensors coupled with a wireless-based data transmission mechanism, real-time data collection becomes feasible. We provide a general description of the system's architecture and its application in a pilot study covering the effects of the devices on concrete properties and data transmission. The dielectric properties of concrete specimens were investigated under natural and accelerated curing/degradation and the results were used in the final design of the antenna device. Furthermore, a pilot test comprising four reinforced concrete columns was used to investigate the range of data transmission from inside to outside of the concrete, the effects of the hardware device on the compressive strength and concrete distribution in the columns, and the data transmission quality in real time under realistic exposure conditions. [ABSTRACT FROM AUTHOR]

In recent years, advanced digital technologies have driven an outstanding paradigm shift in the field of architectural heritage, particularly for building modelling, historical documentation and touristic promotion. Nonetheless, they show great potentialities in the field of assessment and control of the state of conservation of heritage buildings. In particular, close-range and aerial photogrammetry have increasingly relied on low-cost and user-friendly tools and procedures, with a high degree of automation that makes them accessible to specialists who are foremost involved in architectural diagnosis and conservation, rather than in remote sensing sciences. In this framework, this paper provides a scoping review of 117 publications, based on the PRISMA protocol, from Scopus and Web of Science databases, related to the employment of photogrammetric models and methods, with specific focus on the targets and purposes of the diagnostic process, including decay mapping, structural monitoring and modelling, non-destructive investigation and multi-source documentation. In detail, the results point out that current studies mainly support robust processing of large amounts of information from direct observation of surface alterations, systematic correlation between materials, construction characteristics, visible anomalies and experimental measurements, as well as multi-disciplinary collaborative workflows through remote inspection and harmonized data management. Further improvements were identified, including standardization of acquisition procedures, automatization of elaboration pipelines, integration of real-time data, validation of diagnosis decision-making support tools and scalability to networks of assets. [ABSTRACT FROM AUTHOR]

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An extended hybrid method for the analysis of the symmetric structural behavior of segmental tunnel linings is proposed. Their deformations cannot be determined by the traditional hybrid methods when the convergences are close to the serviceability limit states (SLSs). Two real-scale tests are employed for the validation of the proposed method. It involves structural analysis that is based on transfer relations. They represent analytical solutions of the linear theory of thin circular arches, and they contain the symmetric mode of rigid-body displacements. The method is termed hybrid because it is based on two types of input, namely the external loading and experimental data of displacements monitored during the test. It is termed extended because, additionally, the vertical and horizontal convergences are employed to produce more accurate structural deformations than obtained by the traditional hybrid method. The latter is found to be unsuitable for structural analysis after sudden failure has occurred in the vicinity of segmental interfaces. At the respective load steps, the structures were in convergence-related serviceability class C, referring to endangered serviceability. The local failures occurring at these load steps resulted in a rapid increase in the structural deformations and fast attainment of the SLS. If, in convergence-related serviceability class C, local failures at segmental interfaces are detected, the strengthening of the structure is necessary. This cannot be delayed to the attainment of serviceability class D, i.e., to reaching the SLS.

Concrete structures are susceptible to several factors during their life cycles, which can cause various problems. This situation can be avoided in many cases if Structural Health Monitoring (SHM) is used. However, such monitoring is often expensive due to the large number of sensors and the use of data acquisition systems (DAQ). In this context, self-sensing cement composites (SSCCs), monitoring themselves without sensors by incorporating conductive fillers in their composition, provide a better piezoresistive effect. In this research, the Arduino platform and analog to digital converters (ADC) modules were tested, and a prototype of a low-cost DAQ was developed for monitoring SSCCs. The devices were analyzed from the compression tests on the mortar specimens, and the results were compared to measurements obtained from the reference equipment (professional DAQ). The results showed a good sensitivity and an adequate correlation between both devices in some cases. It showed that the Arduino platform has the potential to be used in the experimental monitoring of SSCCs, however it needs to be combined with an ADC module.

The aim of this paper is to investigate whether existing generic fragility curves for various residential building typologies can be safely applied for the vulnerability assessment of school buildings. We select three representative typologies of actual reinforced concrete (RC) school buildings in Thessaloniki, Greece and we conduct a detailed fragility analysis combining field inspection and structural monitoring data to advanced numerical modeling. Building-specific fragility and vulnerability curves are derived for the three school buildings based on 3D incremental dynamic analysis (IDA) of the calibrated numerical models. The comparisons of the developed curves with generic ones showed their significant differences. [ABSTRACT FROM AUTHOR]