Theoretical and experimental investigations of anchoring force loss behavior for prestressed ground anchors

Abstract

Anchoring force loss is critically concerned for the in-service performance of prestressed ground anchors. This time-dependent loss of pretension exerted at the anchor head is caused primarily by stress relaxation, which integrally manifests the rheological properties of the anchor and the geomaterial in which the anchor is embedded. A load-transfer modeling framework was established to derive the time-dependent anchoring force response. The modeling parameters were directly calibrated via element-scale pullout stress relaxation test using a specially developed setup. The applicability and effectiveness of this analytical modeling framework were verified via large-scale laboratory model tests and in situ tests of prestressed anchors. The predictions derived using the presented modeling framework were in good agreement with measurements in both laboratory model tests and in situ tests, particularly for evolutions of anchoring force over time. Sensitivity evaluation of the model parameters was performed to study their respective impact on the anchoring force loss response. This work can provide insights into the understanding of the anchoring force loss behavior of prestressed ground anchors and facilitate their design practice for in-service performance.