Research on Preload Loss Prediction of Clamp Bolt Considering Cable Creep of Galvanized Layer
The main cable clamp of the Guangxi Longmen Bridge was considered as a research object to study the preload loss and prediction model of clamp bolts in suspension bridges during the construction and service stages.First,based on the time hardening theory and indoor experiments,the nonlinear regression fitting of the main cable in its axial direction and clamp bolt creep parameters considering the creep of the galvanized layer of the cable were performed,respectively.Second,the fitting parameters were verified using the established local finite element model(FEM)of the cable clamp.The relationship between preload loss in the bolt and time was studied.In addition,a finite element model of the Longmen bridge was established,and the typical preload loss of the cable clamp bolts in the bridge was simulated.The results showed that for material creep,the FEM calculation value was 6％lower than the formula value,and the FEM calculation error at 10 000 h was less than 10％after the bolt was tensioned.The cable clamp bolt should be tested and re-tensioned within 40 d after the initial tension is completed,and the cable clamp bolt preload should be tested and the bolt should be re-tensioned again within 2 years and 3 months after the completion of the final re-tension,which can provide technical support for the detection and maintenance of suspension bridge clamp bolts.
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