Generalized Approach for the Formulation of Analytical Model of Hybrid Cable Networks

Abstract

Combining the use of external dampers and crossties as a hybrid system to control unfavorable bridge stay-cable vibrations has been successfully applied on a number of cable-stayed bridges, although knowledge about the mechanics and dynamic behavior of such a system is still limited. In the current paper, a generalized approach is developed for formulating an analytical model of hybrid systems which allows development of an analytical model of a complex hybrid system based on a relatively simple parent system, the analytical model of which either is available in literature or can be more easily derived, and then superpose the effect of the remaining component, which can be either a damper or a crosstie. The validity of the proposed approach is verified using a number of cable systems with various configurations, the characteristic equations of which have been analytically derived in the literature. It will then be applied to a more complex hybrid system with two damped main cables interconnected with a crosstie extended to and anchored on the ground or the bridge deck. The respective impact of the damper and the crosstie on the modal response of a hybrid system will also be discussed. The proposed generalized approach is expected to greatly save modeling effort and provide a convenient and useful tool for evaluating and comparing the effectiveness of different hybrid system layouts in the preliminary design stage.