Abstract:To address the issues of high-frequency noise, local missing and temperature-induced interference in the monitoring data of long-span cable-stayed bridges, a preprocessing workflow integrating data resampling, missing data filling and temperature-induced response separation is adopted. Firstly, the original high-frequency data are resampled to a 2 s interval via the time-window averaging method, realizing both data volume compression and retention of key trend features. Secondly, the missing points are automatically identified through timestamp alignment, and the robust filling of missing data is accomplished using the five-point weighted smoothing method. Finally, the empirical mode decomposition (EMD) technique is adopted to adaptively separate the temperature-induced strain components from the signals, thus eliminating the impact of ambient temperature fluctuations. The preprocessed strain data have been successfully applied to the structural condition early-warning analysis of the bridge, which verifies the engineering applicability of the proposed method, effectively improves the quality of monitoring data and provides the reliable data support for the long-term safety assessment and maintenance decision-making of bridges.