Ground-Based Radar Interferometry for Monitoring the Dynamic Performance of a Multitrack Steel Truss High-Speed Railway Bridge

Abstract

With the continuous expansion of the high-speed railway network in China, long-span railway bridges carrying multiple tracks demand reliable and fast testing procedures and techniques. Bridge dynamic behavior analysis is a critical process in ensuring safe operation of structures. In this study, we present some experimental results of the vibration monitoring of a four-track high-speed railway bridge with a metro–track on each side: the Nanjing–Dashengguan high-speed railway bridge (NDHRB). The results were obtained using a terrestrial microwave radar interferometer named IBIS-S. The radar measurements were interpreted with the support of lidar point clouds. The results of the bridge dynamic response under different loading conditions, including high-speed trains, metro and wind were compared with the existing bridge structure health monitoring (SHM) system, underlining the high spatial (0.5 m) and temporal resolutions (50 Hz–200 Hz) of this technique for railway bridge dynamic monitoring. The detailed results can help engineers capturing the maximum train-induced bridge displacement. The bridge was also monitored by the radar from a lateral position with respect to the bridge longitudinal direction. This allowed us to have a more exhaustive description of the bridge dynamic behavior. The different effects induced by the passage of trains through different tracks and directions were distinguished. In addition, the space deformation map of the wide bridge deck under the eccentric load of trains, especially along the lateral direction (30 m), can help evaluating the running stability of high-speed trains.

A Comprehensive Analysis of Static and Dynamic Load Tests of a Long-Span Cable-Stayed Bridge with a Ground-Based Radar Interferometer

“…A radar interferometer can measure the phase with a sensibility that is a small fraction of its wavelength, while a conventional radar is only capable of measuring the amplitude of the signal received. Therefore, sub-millimeter displacements can be measured by radar interferometry [21]. Fundamentally, GB-radar originates from its spaceborne counterparts [36,37], and it is developed on the basis of two fundamental techniques: Interferometry [38] and Frequency Modulated Continuous Wave (FM-CW) [39,40].…”

“…IBIS-S Plus, the most recent version of IBIS-S, is now equipped with a built-in accelerometer to mitigate the effects of possible movement of the radar head, enabling future researchers to acquire data with improved quality. The radar sensor is essentially an FM-CW radar, transmitting a microwave electromagnetic signal at a frequency range of 17.07-17.35 GHz (Ku band) with a maximum bandwidth of 300 MHz, corresponding to a range resolution of 0.5 m [21]. The basic parameters of IBIS-S are listed in Table 3.…”

“…Generally, the real aperture GB-radar is only able to real-time acquire 1-dimensional displacement data due to its inability to detect the direction of arrival (DOA) of the echo signal [10] whereas the synthetic aperture GB-radar enables the acquisition of 2-dimensional images [14]. Therefore, the real aperture GB-radar is commonly used to measure spot or line-shaped targets such as chimneys [15,16], high-rise buildings [17,18], and bridges [19][20][21] while the synthetic aperture GB-radar is usually applied to large-scale area targets such as dams [13,22], glaciers [23,24], landslides and rockfalls [25,26]. However, the image acquisition of a synthetic aperture GB-radar takes several seconds or even minutes while a real aperture GB-radar is able to perform hundreds of acquisitions per second, allowing them to monitor vibration frequencies of the target [19].…”

Contactless Deformation Monitoring of Bridges with Spatio-Temporal Resolution: Profile Scanning and Microwave Interferometry

“…For the application of microwave interferometry, good overviews are given by Gentile and Bernardini [ 12 ], Bernardini et al [ 13 ], Rödelsperger et al [ 24 ]. Microwave interferometry has also been applied to various types of structures in recent years: bridges [ 8 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ], wind power plants [ 21 ], telecommunication towers [ 32 , 33 ], chimneys [ 24 ] or urban buildings [ 34 , 35 , 36 ]. Publications dealing with the performance evaluation through comparisons with conventional sensors are, for example, [ 8 , 35 , 37 , 38 ].…”

Structural displacement monitoring using ground-based synthetic aperture radar

“…GBRAR systems can be suitable for continuously monitoring fast structural displacements, such as mechanical vibration, with a data acquisition rate of a fraction of a second (Rodrigues and Li, 2021). To this end, various case studies, such as bridges (Huang et al, 2020) and buildings (Alva et al, 2020), have been investigated to evaluate GBRAR capabilities for SHM. A study on the feasibility of vibration monitoring of tall structures by combining a laser scanner and GBRAR was presented by Artese and Nico (2020).…”