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On the basis of static, dynamic and transient analysis for the prestressing cable structures, the parameters to control the
vibration of the system for transient main cables and catwalk of some long-span suspension bridge at the construction
stages with the assistant cables are investigated adopting the method of the finite element considering the geometry
nonlinearity. The review and prospect to control vibration with assistant cables are summarized, the finite element
modeling of the system for transient main cables and catwalk is established, and the influence of the position of the
assistant cables, disposed fashion and the tensile forces upon the critical frequencies of the system for transient main
cables and catwalk is researched. At the same time, the effect of the damp and the tensile forces of the assistant cables on
the equivalent damping ratio of the system for transient main cables and catwalk inside and outside the plane is studied
and the effect to control the vibration of the system is analysed. In the end, the influence of the transformation for the
tensile forces about assistant cables upon those of the transient main cables and catwalk is also investigated. Results
show that, to increase the critical frequencies of the system, the assistant cables should be laid vertically with the main
cables and be located in interim span or between the tower and interim span, and to increase the amount of the assistant
cables can increase the critical frequencies ,and to increase the rigidities of the assistant cables can improve the ones of
the transient main cables but decrease the anti-torsion ability of the catwalks, and to increase the damp of the assistant
cables can improve the vibration of the transient main cables inside and outside the plane but the result is little outside
the plane, and in addition the effect of the rigidities of the assistant cables is larger outside the plane but is little inside
the plane. The results also show that the influence of the change of the tensile forces for the assistant cables upon those
of the transient main cables and catwalk is very little.
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