Research on prediction model for preload loss in cable clamp bolts of suspension bridges

To study the law and prediction models of the preload loss of suspension bridge cable clamp bolts under different influencing factors. This research used creep theory and full-scale experiments to perform nonlinear fitting of bolt creep parameters. Then, different FE models were established to investigate the influence of initial preload, clamp inclination angle, and suspender force on bolt preload, and a preload prediction model with single parameter was fitted. Using the Boltzmann linear superposition principle, a prediction model of bolt preload has been obtained under the coupling of various influencing factors. Finally, the prediction model was validated on the Guangxi Longmen Bridge. The results show that the initial preload has little influence on the bolt preload loss. The bolt preload loss rate increases linearly with the inclination angle of the clamp. Compared with no suspender force, the application of the suspender force can reduce the preload loss, and the bolt preload loss curve does not change significantly when the suspender force varies within the 1500-2000kN range. The error of the bolt preload loss between the calculated value of the prediction formula and the detected value of the bridge does not exceed 6 %. The conclusions can provide theoretical support for the detection and re-tension of clamp bolts in the suspension bridge.