Semi-empirical Model for Predicting the Bearing Capacity of Reinjectable and Prestressed Anchors

One of the most unknown facts related to anchor design is determining of the required anchored length to resist the applied prestressing on the anchor. For this design, it is necessary to estimate the bond stress generated at the bulb-ground contact. In this research, an equation is proposed to estimate the bond stress which was achieved by analyzing 136 anchor performance and proof tests. Additionally, a sensitivity analysis was also conducted to detect the influence of each variable on the bond stress, besides a performance evaluation of the semi-empirical equations for the bearing capacity evaluation. Based on these analyses, it was possible to identify effective vertical stress as the variable causing the most impact on bond stress. The influence of injection pressure, injection number, and penetration resistance index altered with the soil types analyzed. Information about the expected prediction interval of bond stress is provided for each soil type.