In this study, pullout performance tests were conducted on five prestressed ground anchors having different tendon bond and unbonded lengths. The tendon bond lengths of the tested anchors varied from 4 to 10 m, whereas the unbonded lengths were in the range of 8–16 m. The tests were performed separately on a dense, gravelly sandy soil slope with an inclination of 90° in Cottbus, Germany. The anchors were inclined downwards at an angle of 15° below the horizontal. The results indicated that three of the five anchors did not satisfy the acceptance criteria as outlined in DIN 4125 Standards. According to the acceptance criteria, the line that was composed of the elastic displacements of the unbonded length had to remain between two specific limit lines. Although the elastic displacements of the unbonded tendons were taken into account for the acceptance of the anchors, the length of the unbonded tendon did not have a significant effect on stability. The anchors having unbonded lengths of 8, 13, and 15 m failed, whereas the anchors with unbonded length of 9 and 16 m were accepted after the termination of the performance tests. However, the tendon bond length was proved to be an important parameter that contributed to the acceptance of the tested anchors. Test results indicated that anchors having tendon bond lengths longer or shorter than 6 m were rejected.
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The authors sincerely thank Prof. Dr. Lutz Wichter from Geotechnical Engineering Department of Brandenburg Technical University for providing the prestressed ground anchors and the equipment for conducting the pullout performance tests.
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Ozhan, H.O., Guler, E. Critical Tendon Bond Length for Prestressed Ground Anchors in Pullout Performance Tests Conducted in Sand. Int J Civ Eng 16, 1329–1340 (2018). https://doi.org/10.1007/s40999-017-0261-0
- Anchor tendon coefficient
- Performance test
- Prestressed ground anchor
- Tendon bond length
- Unbonded length