Practical Simplified Computing Method of Natural Vibration Frequency of Cable-stayed Bridge during Construction Stage

Abstract

In this paper, the vibration analysis model of the cable-stayed bridge is established by using double-mass method, and the formula for calculating its natural frequency during construction is deduced. On this basis, the formula is simplified to obtain the estimation formula of the natural vibration frequencies of the cable-stayed bridge during construction. The structure analysis software MIDAS Civil is used to establish the three-dimensional finite element model of the cable-stayed bridge of Jinan Qihe Yellow River Bridge to analyse the vibration characteristics of Qihe Yellow River Bridge during the construction stage, carry on the spot tracking of the modal test of the construction phase, and at the same time calculate the frequency by using the double-mass method and the estimation formula. The double-mass vibration model, the natural frequency estimation formula, the finite element method analysis and the field modal test results are compared and analysed. Both the test results and the calculated results show that the finite element method can accurately simulate the actual force state of the bridge, and the double-mass model and the estimation formula provide a more accurate and efficient method for calculating the natural vibration frequencies, which provides reference for guiding design and construction monitoring work of the cable-stayed bridge.