Analysis of damper effect on cable-stayed bridge using finite element simulation

Abstract

Cable-stayed bridges generally having common defects such as excessive vibration due to wind action, corrosion and fatigue occurred at the cables supporting member. This study presents two different approaches for the demonstration of the damping effect due to wind action on cable-stayed bridge. The fi rst approach uses a simplifi ed analysis method to study the reaction force at the cable end. A beam element was adopted for modelling the cables and a plate element for modelling the bridge’s deck. The second approach is based on the selected damper system applied at the cable end to determine the reaction response at the bridge models. Two methods are presented in this report with the consideration of bridge geometric effect. The effect of pretension of the cable and the exact treatment of cable sag with the cable weight is ignored. A numerical calculation has been carried out in determining the nominal transverse wind load, the nominal longitudinal wind load on deck and the nominal longitudinal wind load on cables in accordance to the current code of practice. The results generated from MIDAS Civil software have been used for comparing the analysis results. The stiffness coeffi cient for the selected rubber damper type was being modelled at the cable end to examine the effect of nominal and combined wind action at critical locations. The effectiveness of using the rubber damper to suppress the effects of wind was investigated through superposition of these rubber dampers at the maximum reactions at the cable end. It was found that the damper system adapted on the cable-stays has signifi cant infl uence on suppressing the action due to wind.