关键词: 桥梁工程；索力追踪；峰值提取；结构健康监测；频率法

Abstract: To precisely obtain the dynamic variation behavior of cable-stayed cables during the operation of cable-stayed bridges, and identify the stayed cable natural frequency and cable force, an intelligent cable force tracking strategy method based on the vibration data of cables was proposed. The proposed method took the acceleration response of the stayed cable as input and implemented the fast Fourier transform method to convert the time-domain acceleration signal into a frequency-domain power spectral density map, so as to extract the vibration frequency information of the stayed cable. Subsequently, based on the peak-picking algorithm, the power spectral density map was processed to achieve automatic search and extraction of peak values, thereby obtaining the natural frequencies of each order of the stayed cable. Based on the Laida criterion method, the peak spacing and peak relative height difference were discriminated to eliminate the pseudo-peaks, thereby ensuring the accuracy of identifying the natural frequency of the stayed cable. Finally, based on the vibration string theory, the cable force value of the stayed cable was calculated out according to its natural frequency and geometric parameters, achieving a rapid conversion from natural frequency to cable force of stayed cable. The research results show that the proposed method can quickly and efficiently obtain the frequency of each order of the stayed cable and the corresponding information of cable force, and can efficiently distinguish the authenticity of peaks in spectrograms, which has high accuracy and stability in identifying cable force. The proposed method has been successfully applied to the structural health monitoring data of a full-scale cable-stayed bridge, which proves the capability and reliability of the proposed method in practical engineering.

Key words: bridge engineering; cable force tracking; peak-picking; structural health monitoring; frequency method