Study On Cable Force Measurement Of Two Exceptional Structural Cable

In currently, the method of cable force measurement based on vibration-frequency ofstring theory is most widely used in engineering. Its accuracy can satisfy basically forconventional cable force measurement. But for the cable with an external damper and strandstay cable with HDPE shell, the research is still lack of that the conventional method whetherbe apply to these two exceptional structural cables. Research of cable force measurementmethod for exceptional structural cable rely on two large-span Cable--Stayed bridges, the mainconclusion of this paper include the following parts:①Parameter identification of bending stiffness and sag are discussed and impact ofthese parameters to cable force measurement are analyzed based on Xiazhang Sea-CrossingBridge. The results show that the identification bending stiffness is ranging between0.33~0.54EImaxfor parallel wire cable, and the impact of bending stiffness is small for long cable.There is no impact of sag to out-of-plane vibration frequency, while impact is great to in-planefundamental frequency on long cable.②The impact of cable vibration frequency with external damper were analyzed basedon finite element method of complex eigenvalues, and ten cables’ damper-frequency impactcurves were drawn of Xiazhang Sea-Crossing Bridge. The results show that: the importantcharacteristic is discovered that the impact curve has three segments obvious, namely, therising segment, plateau segment and micro-decline segment. There is no impact of externaldamper to out-of-plane vibration frequency, while impact is small to in-plane fundamentalfrequency.③Signal spectrum analysis from different collected points showed that the identifyvibration position for cable with external damper is that upper from damper that the distance isslightly larger than the distance from the damper to deck. It can be increase cable tension testaccuracy through inverse frequency correction factor after considering the coupled vibration.④The results showed that vibration signal can be identified effectively from HDPEshell which corresponding to bound circle. The conclusion demonstrated combined with strandcable tension measurement of East-watergate Bridge.