Simple program to investigate hysteresis damping effect of cross-ties on cables vibration of cable-stayed bridges

摘要

A short computer program has been developed, for the step-by-step dynamic analysis of cables of cable-stayed bridges, connected to each other and possibly with the deck of the bridge, by very thin pretensioned cross-ties and subjected to variation of their axial forces due to traffic or to a variable wind force. A simplified SDOF model, approximating the fundamental vibration mode, is adopted for every individual cable. The geometric nonlinearity of the cables is taken into account by their geometric stiffness. Whereas, the material nonlinearities of the cross-ties include compressive loosening, tensile yielding and hysteresis stress-strain loops. Seven numerical experiments are performed. Based on them, it is observed that if two interconnected parallel cables have different dynamic characteristics e.g. different lengths, thus different masses, weights and geometric stiffnesses, too, or if one of them has a small additional mass, then a single pretensioned very thin wire, connecting them to each other and possibly with the deck of the bridge, proves effective in suppressing, by its hysteresis damping, the vibrations of the cables.