Structural condition assessment of long-span suspension bridges using long-term monitoring data

Abstract

This paper focuses on developing an online structural condition assessment technique using long-term monitoring data measured by a structural health monitoring system. The seasonal correlations of frequency-temperature and beam-end displacement-temperature for the Runyang Suspension Bridge are performed, fi rst. Then, a statistical modeling technique using a six-order polynomial is further applied to formulate the correlations of frequency-temperature and displacement-temperature, from which abnormal changes of measured frequencies and displacements are detected using the mean value control chart. Analysis results show that modal frequencies of higher vibration modes and displacements have remarkable seasonal correlations with the environmental temperature and the proposed method exhibits a good capability for detecting the micro damage-induced changes of modal frequencies and displacements. The results demonstrate that the proposed method can effectively eliminate temperature complications from frequency and displacement time series and is well suited for online condition monitoring of long-span suspension bridges.

Temperature-based structural health monitoring baseline for long-span bridges

“…As an alternative to vibration-based techniques, there is increasing attention being paid to the direct use of temperature and temperature induced responses for both structural identification [18,19] and SHM of long-span bridges [20][21][22]. Logistical advantages of temperature-based SHM (TBSHM) include large signal-to-noise ratios, low required sampling rates, and inexpensive sensing, data acquisition, data storage, and data transmission costs.…”

Sliding life prediction of sliding bearings using dynamic monitoring data of bridges

“…According to Equation (19), the CSD of sliding bearings is affected by the number of modes, the rotation angle of the bridge ends, and the modal coordinates. The rotation angle and the modal coordinate are determined by the number of measuring points.…”

“…To analyse the effect of the number of measuring points on the estimated CSD of sliding bearings, the numbers of measuring points include 19,9,4, and 3, which correspond to measuring points at the twentieths, tenths, fifths, and quarters of the span of the girder. The estimated CSDs obtained from the proposed MRASA are shown in Figure 9a.…”

“…The major part of the cumulative sliding displacement is obtained from the vehicle‐induced dynamic displacement. In general, the displacement of bridge bearings is monitored by the displacement sensors with a frequency as small as 1 Hz or smaller . The low‐frequency displacement sensors cannot record the high‐frequency bearing displacement information.…”

“…In general, the displacement of bridge bearings is monitored by the displacement sensors with a frequency as small as 1 Hz or smaller. [16][17][18][19][20] The low-frequency displacement sensors cannot record the high-frequency bearing displacement information. Additionally, the main girder will vibrate with various modes, including relatively high-frequency modes, for practical bridges subject to vehicle/wind loads.…”