Correlation analysis of the wind of a cable-stayed bridge based on field monitoring

This paper investigates the correlation of wind characteristics monitored on a cable-stayed bridge. Total five anemoscopes are implemented into the bridge. Two out of 5 anemoscopes in inflow and two out of 5 anemoscopes in wake-flow along the longitudinal direction of the bridge are installed. Four anemoscopes are respectively distributed at two cross-sections. Another anemoscope is installed at the top of the tower. The correlation of mean wind speed and direction, power spectral density, the turbulent intensity and integral length of wind in flow at two cross-sections are investigated. In addition, considering the non-stationary characteristics of wind, the spatial correlation in time-frequency is analyzed using wavelet transform and different phenomenon from those obtained through FFT is observed. The time-frequency analysis further indicates that intermittence, coherence structures and self-similar structures are distinctly observed from fluctuant wind. The flow characteristics around the bridge deck at two positions are also investigated using the field measurement. The results indicate that the mean wind speed decrease when the flow passing through the deck, but the turbulence intensity become much larger and the turbulence integral lengths become much smaller compared with those of inflow. The relationship of RMS (root mean square) of wake-flow and the mean wind speed of inflow is approximately linear. The special structures of wake-flow in time-frequency domain are also analyzed using wavelet transform, which aids to reveal the forming process of wake-flow.

[1]  Douglas A. Smith,et al.  Coherent gust detection by wavelet transform , 1998 .

[2]  Yi-Qing Ni,et al.  Technology developments in structural health monitoring of large-scale bridges , 2005 .

[3]  J. B Frandsen,et al.  Simultaneous pressures and accelerations measured full-scale on the Great Belt East suspension bridge , 2001 .

[4]  Mohammad Azarbayejani,et al.  Entropy-based optimal sensor networks for structural health monitoring of a cable-stayed bridge , 2009 .

[5]  Jinping Ou,et al.  Structural Health Monitoring in mainland China: Review and Future Trends , 2010 .

[6]  Yi-Qing Ni,et al.  Variability of measured modal frequencies of a cable-stayed bridge under different wind conditions , 2007 .

[7]  Ana Elena Scarabino,et al.  Characteristics of some organised structures in the turbulent wind above and within a spruce forest from field measurements , 2003 .

[8]  Ahsan Kareem,et al.  Time-frequency analysis of wind effects on structures , 2002 .

[9]  E. Terradellas,et al.  Wavelet methods: application to the study of the stable atmospheric boundary layer under non-stationary conditions , 2001 .

[10]  J. R. Wu,et al.  Field measurements of boundary layer wind characteristics and wind-induced responses of super-tall buildings , 2008 .

[11]  D. Delaunay,et al.  Comparison of full-scale measurement and computation of wind effects on a cable-stayed bridge , 1994 .

[12]  A. Kareem,et al.  First- and Higher-Order Correlation Detection Using Wavelet Transforms , 2003 .

[13]  Gul Agha,et al.  Structural health monitoring of a cable-stayed bridge using smart sensor technology: deployment and evaluation , 2010 .

[14]  Yl L. Xu,et al.  Buffeting response of long-span cable-supported bridges under skew winds. Part 2: case study , 2005 .

[15]  Zhi Zhou,et al.  Structural Health Monitoring System for the Shandong Binzhou Yellow River Highway Bridge , 2006, Comput. Aided Civ. Infrastructure Eng..

[16]  Hiroshi Katsuchi,et al.  Full-Scale Measurement of Akashi-Kaikyo Bridge during Typhoon , 2001 .

[17]  Muhammad R. Hajj,et al.  Characteristic time scales of velocity and pressure events , 2005 .

[18]  Muhammad R. Hajj,et al.  Analysis of atmospheric wind and pressures on a low-rise building , 1998 .