Analytical And Experimental Study Of Vibration Characteristics Of Two Cables Structure With Additional Cross-link

As the main component of cable-stayed bridge, the main role of cables is to transmit the bridge girder and various external load to the bridge tower. Due to the light weight of the cable and large flexibility, cables are easy to produce vibration under the extrinsic incentives, such as wind and rain, and the big vibration is likely to lead cable anchoring section to cracks, undermine its anti-corrosion system, and reduce the life of the cable. Big vibration can upset the traffic and pedestrians, with the increase of span cable-stayed bridge, the inhibition of the vibration of the cable also is particularly important. In engineering it is often used to install dampers, changing the cable’s pneumatic surface, and install cross-ties measures to suppress the vibration of the cable. Pneumatic measure damping mechanism is very complex, and is single for external incentive, damper will be limited to the cable span increases, and auxiliary cable connect each independent cable into cable net structure, reduce the effective length of cable, and make each cable vibration overlapping, significantly improve the natural vibration frequencies of cable net system. But the assistant cable mechanism is not yet clear, optimization meth ods have not been established, and auxiliary cable suspension needs further research.Based on the two conditions:(1)cable vibration amplitude is not large, the auxiliary cable is in a state of tension and relaxation will not happen;(2)Auxiliary cable size is smaller, ignoring the influence of the vibration of auxiliary cable vibration on main cables. The auxiliary cable is equivalent to the elastic additional cross-link. This topic mainly study the slight vibration of cables, ignoring the influence of the vibration of auxiliary cable vibration on main cables. Because of the complexity of the cable net structure, building simplified the structure of double cable network with additional cross-ties and system structure’s differential equations. Do limit parameter analysis on the rigidity of the transverse connection stiffness being infinity and zero and do parameter analysis on the rigidity of the transverse connection stiffness between infinity and zero. Parameter analysis researches the four parameters such as cable length ratio and segment ratio of the transverse connection and frequency ratio, mass – tension ratio how to influence the first four order in-plane free vibration frequency of the simplified cable net system, and the function of the interaction between parameters.In the end, double cable system experiment was carried out. First, test analysis was carried out on the vibration characteristics of the single cable, to test the inside and outside first two order frequency and damping ratio. Second, install two materials’ lateral connection such as shape memory alloy and nylon line in the position of 0.2L and 0.4L to test the inside and outside first two order frequency and damping ratio. Find that in-plane free vibration frequencies of the system with additional cross-link significantly higher than that of single cable. Do in-plane free vibration theory calculation, comparing the results of theoretical calculation and experimental results, and the error is less than 5%. The accuracy of theoretical analysis of the model and equation is verified, theoretical model and equation also provided convenience for the later research of cable system.