Accurate identification method and practical formula of suspender tension based on tri-segment suspender dynamic model

Abstract

Suspenders are main transmission force and load-bearing components of arch bridges and suspension bridges. The identification of suspender tension in service period is significantly to the normal service state and safety evaluation of structures. Based on the dynamic stiffness theory, this study establishes a tri-segment suspender dynamic model considering the effect of suspender anchorage zone. According to this model, an inverse-analysis characteristic function is established. On this basis, an accurate identification method by two optimization models is proposed, which are solved by the particle swarm optimization (PSO) algorithm, thus realizing the identification of suspender tension. Compared with the identification method of suspender tension based on the uniform equal-section dynamic model, the accuracy of the proposed model is higher. By fitting the data pairs of the suspender tension and frequency generated by the tri-segment suspender dynamic model, a practical formula method of suspender tension is also proposed, which is convenient for engineering use. By modifying the conventional cable tension formula, the practical formula method improves the identification accuracy of suspender tension, especially for short cables. Through a 20 m real cable test, it is proved that the two suspender tension identification methods (the accurate identification method and the practical method) proposed in this study have high identification accuracy and stability.