A method of fundamental frequency hybrid recognition for cable tension measurement of cable-stayed bridges

Abstract

The fundamental frequency of the cables in a cable-stayed bridge is an important parameter for the cable tension. This paper analyzes the mechanical model of cable tension measurement and the FFT spectral decomposition of acceleration signals. By comparing amplitudes in the vicinity of the fundamental frequency, an advanced approach of power spectrum measurement for ultra-low fundamental frequencies is proposed, and a new hybrid recognition method is established through combining the power spectrum with the cepstrum. Based on this method, a cable tension measurement system is developed using Matlab. The experimental results show that the mechanical model of cable tension measurement and the hybrid recognition method of fundamental frequencies are effective for monitoring and analyzing large span cable-stayed bridges. They not only improve the articulation of recognition of fundamental frequencies and cable measuring accuracy, but also provide an important approach for solving other nonlinear pattern recognition problems with ultra-low frequencies and strong disturbances.