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As researchers continue to explore wireless sensors for use in structural monitoring systems, validation of field performance must be done using actual civil structures. In this study, a network of low-cost wireless sensors was installed in the Geumdang Bridge, Korea to monitor the bridge response to truck loading. Such installations allow research...
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... render the wireless sensors suitable for use in ambient structural vibration studies, a signal conditioner is proposed to condition the voltage output of accelerometers prior to connection to the wireless sensor. As shown in figure 3, a small (3.5×5 cm 2 ) signal conditioning circuit is designed. The signal conditioner is designed to perform three tasks: (1) amplify, (2) band-pass, and (3) mean-shift sensor outputs. ...
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... By applying modal analysis techniques to examine the SHM of various structures, Aktan et al. [71] found that doing dynamic testing is essential for examining vibrationbased problems. Lynch et al. [72] used a FB modal analysis technique for the geumdang bridge in Korea to understand the structural responses of the bridge. Comanducci et al. [73] applied a similar strategy to a suspension bridge for the dynamic impact of wind loads to calculate frequencies. ...
The field of structural health monitoring (SHM) has gained significant attention from academia and industry, particularly in the realm of damage detection. This approach allows continuous monitoring of the structural integrity of systems and structures throughout their operational lifespan, leading to reduced dependence on periodic inspections and lower maintenance costs. Importantly, this method enables the assessment of structural degradation without causing actual damage to the structure itself. Over the past four decades, various evaluation methods for SHM have been developed, with concrete buildings benefiting greatly from their implementation. Among these methods, vibration-based techniques provide a quick and efficient way to assess the overall health of a structure. Specifically, frequency-based techniques are commonly employed within the vibrations-based SHM (VBSHM) framework, although extracting these parameters through algorithm development can be a complex and time-consuming task. This research aims to review VBSHM with a focus on modal parameters, exploring both traditional and modern methodologies to enhance the accuracy of structural assessment. Additionally, the study highlights the current limitations of research in this field and identifies available studies for further exploration.
... This section briefly describes the experimental case study and then reports the damage identification results using the proposed approach. The acceleration data for the case study (the Old ADA Bridge) are freely available online (Kim et al. 2021b) and described in Kim et al. (2021a). ...
... The authors gratefully acknowledge the availability of data recorded on the Old ADA Bridge, freely available in Kim et al. (2021b). ...
In the last few decades, structural health monitoring (SHM) has proven a helpful tool to support the maintenance and management of civil infrastructure. However, typical measurement networks are expensive and require considerable initial efforts. The user-friendliness and interpretability of the outcome of SHM systems are crucial factors in motivating infrastructure owners and decision-makers to sustain their costs. For this reason, simple algorithms that provide structural parameters with direct physical interpretability for professionals familiar with the typical quantities involved in structural engineering are still the most used in field applications. This paper proposes an original method to identify curvature influence lines of bridges and viaducts only using the structural acceleration response induced by vehicular loads. Acceleration time histories collected at sparse locations through standard accelerometers are employed. In contrast to SHM approaches based on modal parameters, the proposed method does not need strict synchronization, thus being suitable for wireless and low-cost monitoring solutions. Identified influence lines are used to define a spatially dense damage indicator for accurate localization of structural anomalies with a clear physical meaning. Experimental results obtained for a steel truss bridge analyzed in different damage conditions prove the efficacy of the proposed method for situations where modal-based approaches may fail.
... Long-term and continuous deployments for structural health monitoring are still relatively rare. Notable studies of long-term deployments of WSN system in literature are the cable-stayed bridges Jindo bridge [16,17], Geumdang bridge [18] and Hwamyung bridge in Korea [19], New Carquinez Suspension Bridge [20] and Golden Gate Bridge in the US [21], Fatih Sultan Mehmet Bridge in Turkey [22], Gi Lu bridge in Taiwan [23], and Ferriby Road Bridge in UK [24]. Implementation for continuous seismic monitoring application is even more limited. ...
... Comparisons of piers accelerations in lateral direction (bridge axis) and their frequency spectra obtained from sensor nodes on the pier caps during the largest NFE (July 17th,2018). Acceleration responses: (a) Nodes 7,11,12,14, (b)Nodes 15,17,18,20. Fourier spectra of accelerations: (c) Nodes 7,11,12,14, and (d)Nodes 15,17,18,20. ...
... Acceleration responses: (a) Nodes 7,11,12,14, (b)Nodes 15,17,18,20. Fourier spectra of accelerations: (c) Nodes 7,11,12,14, and (d)Nodes 15,17,18,20. ...
A 45-month continuous seismic monitoring of a multi-span highway bridge by wireless sensor network (WSN) is described in this paper. The WSN monitoring system is developed using a simultaneous high-speed flooding technique and deployed to monitor a continuous 12-span 381.8 m long highway bridge in Katsuta city, Ibaraki prefecture, Japan. The WSN monitoring system consisted of 20 triaxial accelerometers placed on bridge girder, pier caps, abutment, and on the ground. The monitoring system has successfully recorded seismic responses of 63 earthquakes from August 2017 to December 2020. The paper describes the WSN monitoring system, analyses of seismic responses, and structural assessment using the recorded seismic responses. The analyses include investigation on seismic response characteristics of girder, piers, and bearings, system identifications, and seismic performance evaluation of isolation bearings. The WSN monitoring system provides high quality of seismic responses. Evaluations of ground motions recorded by WSN with the existing strong motion KNET seismograph network have demonstrated the accuracy, reliability, and robustness of WSN monitoring system. Using three system identification methods, dominant bridge modal parameters and their variations with respect to earthquake levels were investigated. High-frequency filtering effect was utilized as indicator in assessment of isolation bearing performance. Systematic classification by clustering algorithm was conducted to determine whether the isolation bearings have functioned normally.
... Modal parameters are among the most popular damage-sensitive features (DSFs) in practical SHM applications due to their direct physical interpretation [4][5][6]. Indeed, the user-friendliness and interpretability of the outcome of SHM systems is a crucial factor in motivating infrastructure owners and professionals to adopt SHM systems and sustain their initial costs. ...
Due to growing traffic demand, aging civil infrastructure raises the need for reliable tools to monitor structural health conditions, usable to plan informed maintenance and emergency management. Several structures with historical and monumental importance are instrumented with structural health monitoring (SHM) systems nowadays. However, even the failure of “minor” viaducts could endanger the safety of travelers and goods. Lately, dense wireless sensor networks (WSNs) based on MEMS devices are used to cut costs and simplify the deployment of SHM systems while collecting as much information as possible. However, dense WNSs are affected by data management, synchronization, and battery replacement issues, which make them unappealing for widespread use. This study presents an original damage identification algorithm based on sparse sensor networks. Traveling vehicles are exploited to obtain spatial information and accurately identify the location of structural anomalies. The curvature influence line of the monitored bridge can be calculated by processing the acceleration response measured at a given instrumented location through a low-pass filter. In this procedure, sensors operate individually, not needing energy-consuming synchronization. The proposed identification algorithm is verified on real data collected on a steel truss bridge subject to artificially induced damage.
... In recent years, structural health monitoring (SHM) systems have been widely implemented in civil infrastructure systems, such as bridges [17,18], high-rise buildings [19,20], large-span spatial structures [21,22], and dams [23,24]. These SHM systems provide a large amount of monitoring data for using data-driven approaches to predict the variation of structural responses, such as displacement [25], structural temperature [26], elastic modulus [27], and mechanical strains [28,29]. ...
... These two indexes are calculated in Eqs. (16)(17). The correlation coefficients are generally greater than 90 %. ...
... The major points fall into the 99 % confidence interval (orange area) according to the figure, which means the prediction results are reliable. RRMSE is used to evaluate the prediction performance of the designed network as described in Eq. (17). The RRMSEs for NCT1 and NCT1-Re are 1.86 × 10 − 1 and 1.04 × 10 − 1 , respectively, whereas the values of this index for NCT2 and NCT2-Re are 3.13 × 10 − 1 and 4.57 × 10 − 1 . ...
... Table 2 Aktan et al. [88] reviewed the SHM of various structures using modal analysis techniques and revealed that conducting dynamic tests is essential to investigate vibration-based problems. The SHM of Geumdang Bridge in Korea was performed using a frequencybased method by Lynch et al. [89]. In this method, the structural responses of the bridge were evaluated using a modal analysis technique. ...
Structural health monitoring (SHM) has become an important and hot topic for decades in various fields of civil, mechanical, automotive, and aerospace engineering, etc. Estimating the health condition and understanding the unique characteristics of structures through assessing measured physical parameters in real-time is the major objective of SHM. As a result, signal processing becomes an essential and inseparable approach of vibration based SHM research. The basic goal of using signal processing is to identify the changes or damages from the vibration signals of the dynamic system to detect, locate, and quantify any damages existing in the system. This paper aims to present a comprehensive review of the recent progress that used signal processing techniques for vibration based SHM approaches. Furthermore, the feature extraction process through the signal processing techniques is the basic skeleton of this review. The application of signal processing techniques in structural damage identification procedure is classified into two approaches, namely (i) time-domain and (ii) frequencydomain. Experimental studies have assessed the potentials of the signal processing techniques in two aforementioned domains to enhance the vibration-based structural damage detection subjected to environmental effects. While there have been multiple review studies published on vibration-based structural damage detection, there exists no study in categorizing the signal processing techniques based on the feature extraction procedure that belongs to time and frequency domains for SHM purposes. This review fills this gap and presents a holistic summary of the cutting-edge methodology and technique applied in the relevant research field.
... After pioneering studies introduced by Straser and Kiremidjian [52,53], several researchers focused on the continuous development of wireless monitoring systems [54][55][56]. The following studies were carried out by researchers who performed validation tests on prototype structural wireless monitoring systems of bridges and other structures [57][58][59]. The results supported that wireless monitoring systems were found to be more feasible, reliable and cost-effective than traditional wired systems. ...
Long-span bridges constitute one of the most critical lifelines in countries where they are constructed since they shorten transportation by providing passage through large waterways, such as rivers, channels, dams, and the sea. Owing to its geographical location, Turkey is a transit country between Asia and Europe. As long-span bridges are subject to heavy traffic and seismic hazards in Turkey, monitoring their structural health and performing their maintenance in a timely and cost-effective manner is essential. These bridges pose maintenance challenges due to their sizes. Because of their high towers and hard-to-access cables in general, the most reliable method of monitoring the structural condition of such bridges under service is to build structural health monitoring (SHM) systems. This paper reports on the results of a study in which the SHM systems of long-span bridges in Turkey, which are among the largest bridges across the world, are described. The characteristics of these systems utilized are explained in detail. In addition, SHM data acquired on the Fatih Sultan Mehmet Bridge during a recent offshore event on 26th September 2019, the Silivri Earthquake (Mw 5.8), are analyzed. The findings are validated using experimental research results presented in the literature, and the comparison was indicated good agreement to identify the bridge’s dynamic characteristics. Finally, problems encountered in SHM systems because of extreme loads are explained, and recommendations are provided for future applications.
... There are many studies describing efforts to monitor individual bridges (e.g., Brownjohn et al., 1999;Chang and Im, 2000;Wong, 2004;Lynch et al., 2006;Staquet et al., 2007;Hoult et al., 2010;Hussain et al., 2010;Koo et al., 2013;Middleton et al., 2016;Moreu et al., 2017;Selvakumaran et al., 2018;Cusson and Ozkan, 2019;Kariyawasam et al., 2019a). Webb (2014) observed that often monitoring systems do not deliver the necessary insights desired by bridge owners and managers; a clear statement upfront of what value the system may deliver is often lacking. ...
Structural health monitoring (SHM) has the potential to transform the bridge engineering industry by providing stakeholders with additional information to inform decisions about the design, operation, and management of bridges throughout their life. This chapter gives guidance on SHM for engineers who design, build, operate and maintain bridges. There remain numerous technical challenges to overcome when deploying SHM systems, but the most important issues to be considered are how to decide what information is required and then how to develop a strategy to deliver this information in a form that is easy to interpret so as to inform decision making. This chapter presents a series of case studies to show how SHM systems can be used in practice to obtain valuable data and to explore the challenges faced during such projects. Future directions for emerging technologies and approaches for future research and management of bridge SHM systems are also discussed.
... Heo et al. [3] developed smart monitoring with Transmission Control Protocol/ Internet Protocol (TCP/IP) network protocol over Bluetooth technology. Lynch J. P. et al. [5][6] developed the low-power wireless monitoring system and successfully detected the structure's damage. However, these devices send large numbers of raw data, which need to be further processed on the PC. ...
Ultrasonic wave is widely used in Structure Health Monitoring (SHM) systems. A piezoelectric transducer (PZT) is one of the most widely used sensors to acquire the structure's ultrasonic wave. As today's world is digital, it is necessary to digitize the traditional analog PZT sensing system. This paper describes the development and analysis of a digital ultrasonic sensing device (DUSD) for PZT sensors. We removed the complexities of the analog circuit by interfacing the microcontroller directly with the charge amplifier circuit. The microcontroller used in this research is a 32-bit ARM Cortex-M4 with in-built FPU (Floating Point Unit) and DSP (Digital signal processing) instructions. These features make it possible to compute complex signal processing algorithms and methods in the controller itself. The developed sensing device can communicate with the user and other devices using Universal Asynchronous Receiver/Transmitter (UART). The user can select cut-off frequencies of both high pass filters (HPF) and low pass filters (LPF) as well as types of data (ultrasonic waves, damage index) that the user wishes to collect from the device. To illustrate the proficiencies of the device, the ultrasonic wave was collected and evaluated to detect the damage in the test specimen.
... There are efforts by researchers to enable noncontact and reference-free inspection of the infrastructure, such as using wireless smart sensors (WSS), cameras, or unmanned aerial vehicles (UAVs). In the past, researchers used WSS to monitor bridges (Lynch et al. 2006;Jang et al. 2010;Moreu et al. 2017). Similar to other sensors, WSS require some degree of access to the structures. ...
Railroad bridge inspectors are interested in measuring the maximum total transverse displacement of railroad bridges under trains, but these values are generally not easy to obtain in the field without sensors. Engineers use LVDTs, analog accelerometers, or wireless smart sensors (WSS). However, these sensors need to be attached to the bridge prior to the train-crossing event, which requires time, costs money, and is unsafe for engineers. This paper describes the design of a new sensor-equipped, low-cost unmanned aerial vehicle (UAV) system that enables the safe, cost-efficient, and noncontact total transverse displacements measurement of railroad bridges. The new system integrates laser and camera measurements from a UAV flying near the moving structure. The design and assembly of the new system is followed by methodology, field experiment, and results. The authors compared the estimations of the new system with ground-truth data obtained using an LVDT to quantify the capabilities of the new system. The results support the value of the proposed method to measure noncontact railroad bridge displacements in the field.
