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The automatic record of the response of the FBG sensor to (a) a pickup, (b) a truck crossing the instrumented bridge.
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Long-term structural health monitoring (SHM) plays an important role in the safety of public transport infrastructure such as bridges or tunnels and warns in the event of any emerging problem. This article describes development and testing of system based on fiber Bragg grating (FBG) sensors that can detect changes in strain and temperature. The fi...
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This paper investigates a strain-based structural health monitoring (SHM) method for damage detection and propagation assessment in composite sandwich structures. As case example, an idealized Airbus A-340 spoiler is considered. Critical failure modes of such sandwich structures composed of fiber reinforced polymer (FRP) face layers and a honeycomb...
Citations
... Strain is a critical parameter for assessing structural health, as it reflects the stresses and deformations within the material [15,16]. Structural health monitoring (SHM) evaluates structural strength by detecting strain distributions and variations, providing early warnings for excessive or localized strain, and thus reducing the risk of accidents [17,18]. ...
Ships, as thin-walled structures, experience various structural responses at critical components and may even fail under sustained time-varying wave forces. Understanding the structural behaviors of key components during operation is essential for accurate ship safety assessments. The lack of an effective strain monitoring system that integrates both high spatial resolution and dynamic monitoring capabilities affects the timely detection of these structural responses. This paper presents a high spatial resolution dynamic strain monitoring system using optical frequency domain reflectometry, achieving a system spatial resolution of 0.11 mm, a sensing spatial resolution of 20 mm, and a sampling frequency of 10 Hz. A box girder model of a river-sea-going ship is employed to simulate structural responses under wave-induced conditions. Simulation results validate the system’s accuracy. By analyzing strain distribution and variation, this study explores the dynamic collapse behavior of structures under wave forces.
... These sensors capture the stress-strain response under different load conditions. This helps assess the ultimate strength of the bridge [6,7]. Additionally, sensors such as static leveling instruments, displacement monitors, and inclinometers can track spatial deformation and displacement changes of the main beam during operation. ...
Single-pier, dual-bearing bridges are susceptible to effects such as concrete creep, thermal expansion, and uneven foundation settlement. When combined with eccentric loading from heavy vehicles, these factors collectively can significantly increase the risk of bridge overturning. To address this risk, a comprehensive analysis of the bridge overturning mechanism was conducted. Considering the current limitations of health monitoring in bearing reaction force (BRF) measurement and risk mitigation, an adjustable intelligent bearing based on pressure sensing and self-locking principles was developed. Its mechanical performance was analyzed under the most unfavorable load conditions. To further validate the approach, a specific experimental bridge was used as a case study. The effectiveness of the force measurement and height adjustment functions was evaluated through moving load experiments. The results showed that the force measurement function accurately captured dynamic BRF changes within a precision range of ±0.1% FS and demonstrated high sensitivity to instantaneous impact effects. The height adjustment function achieved a reaction force change of up to 40 kN within the maximum adjustment range of 1.2 mm, significantly improving the load distribution of the bridge. These findings validated the reliability of the proposed intelligent bearing in real-time monitoring and proactive risk adjustment. This effectively overcomes the limitations of existing bearings, which only perform passive monitoring. Overall, it achieves the real-time monitoring of BRF and proactive control of bridge overturning risks.
... Ref. [17] Comparative tests of concrete beam integrated FBG sensors ...
Optical fiber Bragg grating (FBG) sensors have advanced significantly in the last several years. The use of innovative FBG in temperature and pressure measurement is examined in this study. The benefits of FBGs, such as their compact size, low weight, resilience to corrosion, immunity to electromagnetic interference, distributed sensing, and remote monitoring, have brought attention to the growing research in this field of structural health monitoring of civil infrastructures. In this investigation, a novel model is proposed and implemented using ANSYS workbench and GratingMOD tool. It is shown that the central wavelength of FBG sensors increased from 1 550 nm to 1 556 nm when the temperature rose from 10 °C to 40 °C. In a similar vein, the central wavelength grew from 1 551.166 7 nm to 1 560.056 nm over a pressure range from 100 MPa to 600 MPa. The claimed work will make it possible to calibrate sensors more precisely, guaranteeing accurate data and being useful in monitoring numerous parameters at once, making them beneficial in a variety of applications.
... • FBGs-Previous applications demonstrated the effectiveness of these technologies in the building and infrastructure sectors, such as bridges [29][30][31], concrete, wood [32], and steel structures, where strain and temperature have so far been the dominating measurands of interest. Utilizing conventional FBG sensors for SHM in building façades offers significant advantages over electrical strain gauges. ...
This paper details the comprehensive activities conducted in a laboratory setting to assess the structural health monitoring (SHM) of prefabricated building envelopes. Integrating sensors into building components like curtain wall facades poses challenges but offers opportunities for monitoring structural health, requiring compliance with regulatory standards. The research investigates the possibility of defining a kit of conventional and multi-parameter sensors integrated within the building envelope to monitor its behavior during the performance test conducted. The kit of sensors also includes Fiber Optic Sensors for effectively monitoring building envelope behavior and structural integrity. In this context, the European project InComEss (H2020-GA862597) aims to define a stand-alone solution for SHM using Piezoelectric Energy Harvesting Systems (PE-EHS) for façade monitoring through FBG/FOS system. After analyzing the main façade structural stress, a series of FBGs, accelerometers, and force washers were integrated within a 1:1 scale façade prototype and tested in a laboratory following the test sequence parameters required by the curtain wall standard EN 13830. The data collected were analyzed with the aim of monitoring the façade behavior before and after the tests. The results show that the façade’s performance passed the assessing test criteria without reporting any damages. In addition, the outcomes demonstrated the effectiveness of the defined kit of multi-parameter sensors for the building envelope’s SHM.
... Several solutions already exist to measure the surface deformation state of civil engineering structures. This includes piezoresistive strain gauges, vibrating wire strain gauges [2] and various types of fiber-optic strain sensors [3,4]. The first two are mature solutions, developed already in the first half of the 20 th century. ...
Monitoring the health of civil engineering structures using implanted deformation, temperature and corrosion sensors would further improve maintenance and extend the service life of those structures. However, sensor integration poses a number of problems, due to the presence of cables and on-board electronics. Passive, wireless SAW sensors offer a very promising solution, here. We used commercial SAW devices mounted on steel rebars to carry out an initial feasibility study. Without cables or embedded electronics, we were able to measure the deformation of a concrete beam subjected to bending load. We were also able to measure the temperature continuously over a three-week period.
... SHM methods can be adapted to structures for identifying, locating, and sizing defects. Typical SHM methods applied to concrete structures are vibration [6][7][8], strain monitoring [9][10][11][12][13], and the acoustic emission (AE) method [14][15][16][17][18][19]. The AE method is a passive nondestructive evaluation method that detects elastic waves released from active defects. ...
Basalt fiber-reinforced polymer (BFRP) reinforced concrete is a new alternative to conventional steel-reinforced concrete due to its high tensile strength and corrosion resistance characteristics. However, as BFRP is a brittle material, unexpected failure of concrete structures reinforced with BFRP may occur. In this study, the damage initiation and progression of BFRP-reinforced concrete slabs were monitored using the acoustic emission (AE) method as a structural health monitoring (SHM) solution. Two simply supported slabs were instrumented with an array of AE sensors in addition to a high-resolution camera, strain, and displacement sensors and then loaded until failure. The dominant damage mechanism was concrete cracking due to the over-reinforced design and adequate BFRP bar-concrete bonding. The AE method was evaluated in terms of identifying the damage initiation, progression from tensile to shear cracks, and the evolution of crack width. Unsupervised machine learning was applied to the AE data obtained from the first slab testing to develop the clusters of the damage mechanisms. The cluster results were validated using the k-means supervised learning model applied to the data obtained from the second slab. The accuracy of the K-NN model trained on the first slab was 99.2% in predicting three clusters (tensile crack, shear crack, and noise). Due to the limitation of a single indicator to characterize complex damage properties, a Statistical SHapley Additive exPlanation (SHAP) analysis was conducted to quantify the contribution of each AE feature to crack width. Based on the SHAP analysis, the AE duration had the highest correlation with the crack width. The cumulative duration of the AE sensor near the crack had close to 100% accuracy to track the crack width. It was concluded that the AE sensors positioned at the mid-span of slabs can be used as an effective SHM solution to monitor the initiation of tensile cracks, sudden changes in structural response due to major damage, damage evolution from tensile to shear cracks, and the progression of crack width.
... Several solutions already exist to measure the surface deformation state of civil engineering structures. This includes piezoresistive strain gauges, vibrating wire strain gauges [2] and various types of fiber-optic strain sensors [3,4]. The first two are mature solutions, developed already in the first half of the 20 th century. ...
Monitoring the health of civil engineering structures using implanted deformation, temperature and corrosion
sensors would further improve maintenance and extend the service life of those structures. However, sensor integration
poses a number of problems, due to the presence of cables and on-board electronics. Passive, wireless SAW sensors
offer a very promising solution, here. We used commercial SAW devices mounted on steel rebars to carry out an initial
feasibility study. Without cables or embedded electronics, we were able to measure the deformation of a concrete beam
subjected to bending load. We were also able to measure the temperature continuously over a three-week period.
... The recent trends in the bridge industry involve the development of health monitoring procedures which can maintain the operability and improve the life span of the bridge 10 . The challenge lies in the proper installation and validation before functional use [11][12][13][14] . Authentication of the newly installed SHM systems is extremely important for the start of their operational life 15 . ...
This research focuses on the automation of an existing structural health monitoring system of a bridge using the BIMification approach. This process starts with the Finite Element Analysis (FEA) of an existing bridge for the numerical calculations of static and dynamic parameters. The validation of the FE model and existing SHM system was carried out by the field load testing (Static and dynamic) of the bridge. Further, this study tries to fill the research gap in the area of automatic FE model generation by using a novel methodology that can generate a BIM-based FE model using Visual Programming Language (VPL) scripts. This script can be exported to any FE software to develop the geometry of the FE model. Moreover, the SHM devices are deployed to the Building Information modelling (BIM) model of the bridge to generate the BIM-based sensory model (as per the existing SHM system). In this way, the BIM model is used to manage and monitor the SHM system and control its sensory elements. These sensors are then linked with the self-generated (Internet of Things) IoT platform (coded in Arduino), developing a smart SHM system of the bridge. Resultantly, the system features visualisation and remote accessibility to bridge health monitoring data.
... At present, the quasi-distributed FBG sensors have already been applied in a wide range of industries. SHM is the most active area of application for quasi-distributed FBG sensors [105][106][107][108][109][110][111][112][113]. Several FBG sensing elements could be embedded or attached to the monitoring structures and connected to an optical fiber sensing network. ...
Real-time monitoring of large marine structures’ health, including drilling platforms, submarine pipelines, dams, and ship hulls, is greatly needed. Among the various kinds of monitoring methods, optical fiber sensors (OFS) have gained a lot of concerns and showed several distinct advantages, such as small size, high flexibility and durability, anti-electromagnetic interference, and high transmission rate. In this paper, three types of OFS used for marine structural health monitoring (SHM), including point sensing, quasi-distributed sensing, and distributed sensing, are reviewed. Emphases are given to the applicability of each type of the sensors by analyzing the operating principles and characteristics of the OFSs. The merits and demerits of different sensing schemes are discussed, as well as the challenges and future developments in OFSs for the marine SHM field.
... Jayawickrema et al. [13] investigated the application of an enclosed FBG sensor embedded in a concrete beam for monitoring structural integrity. It was observed that the internal deformations in concrete structures, created by the flexural loading, can be detected and measured by the FBG sensors.Čápová et al. [14] installed sensors containing FBGs in a concrete bridge by attaching those sensors to the reinforcing steel to monitor the prestressing of the structure in the initial phase and later the overall load of the structures, the impacts of temperature changes and traffic intensity. Kaklauskas et al. [15] performed experimental and numerical studies to analyze the strain distribution on RC short tensile specimens by installing tensor strain gauges and FBG sensors in the RB. ...
The detection of bond-slip between the reinforcing bar (RB) and concrete is of great importance to ensure the safety of reinforced concrete (RC) structures. The techniques to monitor the connection between the RB and concrete are in constant development, with special focus on the ones with straightforward operation and simple non-intrusive implementation. In this work, a simple configuration is developed using 10 optical fiber sensors, allowing different sections of the same RC structure to be monitored. Since the RB may suffer different strains along its length, the location of the sensors is critical to provide an early warning about any displacement. Bragg gratings were inscribed in both silica and polymer optical fibers and these devices worked as displacement sensors by monitoring the strain variations on the fibers. The results showed that these sensors can be easily implemented in a civil construction environment, and due to the small dimensions, they can be a non-intrusive technique when multiple sensors are implemented in the same RC structure.
