Study on mechanisms of anchorage creep-induced prestress loss in prestressed systems with varying anchorage lengths

Abstract

Prestress loss poses a significant risk to structural safety and must be carefully considered in the design of prestressed anchors. This study begins by analyzing the relationship between creep in the anchorage zone and prestress loss. Subsequently, creep tests were conducted to determine the creep parameters of the anchorage zone and the differences in creep behavior under varying anchorage lengths were compared. Based on the test results, numerical simulations were performed to investigate the evolution of mechanical behavior during prestress loss and the influence of anchorage length on long-term performance. The results indicated that the coupled process of prestress loss and creep could be characterized as creep behavior under variable load, where the load was correlated with the total displacement of the anchor. During prestress loss, the shear load distribution in the anchorage zone transitioned from a concentrated to a uniform pattern. Specifically, the shear load near the free section decreased while the shear load near the bottom increased. The boundary between these two regions remained relatively stable, ranging between 0.5 m and 0.75 m, regardless of anchorage length. Increasing the anchorage length significantly reduced the prestress loss during the first year. This reduction was attributed to the smaller shear force and creep deformation in the rear section, which constrained deformation in the front section and minimized retraction in the free section of the anchor. However, the effectiveness of increasing anchorage length diminished as the length continued to expand. These findings offer valuable insights into the influence of anchorage length on the long-term service capacity of prestressed anchors, guiding structural design and optimization.