A unified approach for vertical vibration of suspension bridge systems

Due to the small stiffness of the suspension bridge, it is easy to vibrate under live load, and its dynamic problems have become the key to structural design, health monitoring and vibration control. The classical analysis theory of suspension bridges usually needs to make a lot of simplifications to the analytical model, thus its application scope and accuracy is limited; The numerical method has low calculation efficiency and is not convenient for parameter analysis. In this article, a novel exact dynamic analysis method for suspension bridges based on the dynamic stiffness method (DSM) is proposed. First, a double-beam model with several discreate springs are used to simulate the in-plane dynamic model of suspension bridges. Then, the governing differential equations of the system are derived, and the characteristic frequency equation is obtained and solved by employing the DSM and Wittrick-Williams algorithm. The accuracy and availability of the proposed model and method are validated by comparing the results obtained with finite element solutions and field measured data. Finally, the parametric analysis is performed to illustrate the influence law of design parameters on in-plane natural frequencies and mode shapes.