Measurement of Long-Term Periodic and Dynamic Deflection of the Long-Span Railway Bridge Using Microwave Interferometry

Liu, Xianglei; Tong, Xiaohua; Ding, Keliang; Xian, Zhao; Zhu, Lei; Xue-dong, Zhang

doi:10.1109/jstars.2015.2464240

Cited by 23 publications

(13 citation statements)

References 32 publications

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“…The IBIS-S system was developed by the Ingegneria Dei Sistemi (IDS) Company, Pisa, Italy, in collaboration with the Department of Electronics and Telecommunications of Florence University. The IBIS-S instrument consists of a radar unit, a control PC, a power supply unit, and a tripod, with the ability of displacement monitoring in any weather conditions, independent of daylight [10]. The radar unit, a coherent sensor module, can generate, transmit, and receive the electromagnetic signals, and further process the preserved phase information of the received signals to calculate the displacement of the monitored objects.…”

Section: Ground-based Microwave Interferometrymentioning

confidence: 99%

“…The control PC is connected to the radar unit by a standard USB 2.0 interface (Figure 2), and it can be used to configure the parameters and manage and store the measurements. It also allows the user to view the initial results of the key locations in real time [10].…”

Section: Ground-based Microwave Interferometrymentioning

confidence: 99%

“…Therefore, the range resolution ∆R can be calculated using the corresponding continuous-wave signals by ∆R = c 2·B , where c denotes the speed of light in a vacuum. For the IBIS-S system, the bandwidth range B is 300 MHz, and thus a range resolution of up to 0.5 m can be obtained [10]. This means that each object point can be observed separately by not less than 0.5 m from another point along the radial direction [29].…”

Section: Ground-based Microwave Interferometrymentioning

confidence: 99%

“…However, since ground-based microwave interferometry provides a measurement of the line-of-sight displacement, it requires prior knowledge of the direction of motion to evaluate the actual displacement. For the monitored Zhaozhou Bridge in this study, the displacement under environmental excitation factors and traffic loads can be regarded as the projected displacement, which can be calculated by making straightforward geometric projections [10,28].…”

Section: Ground-based Microwave Interferometrymentioning

confidence: 99%

“…Considering that Zhaozhou Bridge is of great historical heritage, no corner reflectors were installed on the lower surface of the central span. The acquired time series displacements along the radar line-of-sight direction were directly calculated by the reflected microwave signal from the natural surface of the arch, which was then vertically projected to obtain the projected time series displacements [10,28]. …”

Section: Dynamic Time Series Displacements Acquisitionmentioning

confidence: 99%

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Dynamic Monitoring and Vibration Analysis of Ancient Bridges by Ground-Based Microwave Interferometry and the ESMD Method

Liu

Yang

et al. 2018

Remote Sensing

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Abstract:In this paper, we propose to conduct a dynamic monitoring and vibration analysis of ancient bridges by means of ground-based microwave interferometry and the extreme-point symmetric mode decomposition (ESMD) method. Ground-based microwave interferometry, a novel non-contact technology with a high accuracy, is used to acquire dynamic time series displacements with environmental excitation factors and a transient load with a car, respectively. The ESMD method, a new alternative to the Hilbert-Huang transform (HHT), is adopted to conduct the instantaneous vibration analysis of Zhaozhou Bridge. Firstly, a series of intrinsic mode functions (IMFs) are obtained together with an optimal adaptive global mean (AGM) curve by using a mode symmetric about the maxima and minima points. Secondly, the instantaneous frequency of each IMF is obtained by the use of a direct interpolation algorithm, which can reconcile the conflict between the period and the frequency for the traditional time-frequency analysis methods. As a representative case, Zhaozhou Bridge, a well-known Chinese ancient bridge constructed more than 1400 years ago, is studied in detail. Four kinds of dynamic time series displacements-two of them acquired by considering only environmental excitation factors for the mid-span and 1/4-span points and the others obtained with the transient load of a car for the mid-span and 1/4-span points-are selected to pursue a comparison of the decomposed IMFs and the instantaneous frequencies to perform the instantaneous vibration analysis of Zhaozhou Bridge. By comparing the results obtained with HHT for the decomposed IMFs and the instantaneous frequencies, the results show that the proposed method has a powerful ability to evaluate the instantaneous dynamic response of ancient bridges.

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Section: Ground-based Microwave Interferometrymentioning

confidence: 99%

Section: Ground-based Microwave Interferometrymentioning

confidence: 99%