Fatigue performance of ultra-high-strength cold-rolled prestressed large-diameter steel bars in prefabricated pier

Prestressed bridge piers are widely used in cross-sea, urban municipal, and mountainous bridge construction. Conventional precast bridges usually use prestressed steel strands for anchoring, resulting in the corrosion and fracture of steel strands. A new high-strength cold-rolled prestressed coarse steel bars as a novel anchoring system is adopted as the research object. Considering the deterioration effect at the root of the thread, the influence of the number of cold rolling and tempering temperatures on the initial cracks and fatigue performance of steel bar is analyzed. Further, the small and full-scale fatigue tests on the steel bars are also carried out. The fatigue lifetimes of the two are compared, and a fatigue life assessment model based on the specimens of cold-rolled coarse steel bars is established. The average error of this prediction model is about 5%, indicating a favorable predictive performance.