A Stabilization Scheme with the Flexural Rigidity for Dynamic Responses of Cables Subjected to Multi-frequency Loads Hyun Su Kim
ABSTRACT This paper presents the accuracy of the acceleration response and the stabilization scheme with the flexural rigidity for the acceleration response subjected to multifrequency loads, especially concentrated loads in cable free vibration test. Recently the constructions of the cable supported bridges are advanced activelyall over the world. Moreover, the length of the span is increasing, for example, Incheon Bridge, Kwangyang Bridge. Thus, it is very important to analyze and predict the behaviors and the characteristics of cables which support a whole bridge. Because the span increases in length, there are many researches and experiments about understand responses, dominant frequencies and damping ratios, etc. In the former study about the cable free vibration test, the analyzed displacement is nearly equal to the measured displacement. However, the analyzed acceleration is very different from the measured acceleration. As for the early study result, it is difficult to predict the responses of cables. By using the flexural rigidity which helps to stabilize the displacement response of the slack cables, solve the problems about inaccurate and unstable acceleration in time domain. The elastic catenary cable elements are applied in the static analysis and non-linear dynamic analysis is adopted. The beam element and arch element are used when assembly stiffness matrix to apply the bending stiffness. A stabilization scheme with the flexural rigidity, beam element and arch element, carries more accurate and stable resulta. Also, this paper estimates the optimal flexural rigidity in the frequencydomain. The accuracy of the acceleration response has a good accuracy with the optimal flexural rigidity. The numerical example is the free vibration test applied to a concentrated load. This is performed to demonstrate the validity and the stability of the proposed model compared with cable model without bending stiffness.
Key Word Stabilization, Flexural Rigidity, Cable, Free Vibration, Multi-frequency Load, Dynamic Equilibrium Equation
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