Performance and design of post-installed large diameter anchors in concrete

• Four combined-anchor types were studied in the prototype experiment.
• The modified design equation for large diameter anchor was proposed.
• Experiment results of the ultimate load were predicted by the modified design equation.
• Both performances of experiment and design concepts complement the deficiency status of large diameter anchor effectively.

Knowledge deficiency in design concepts promotes the performance investigation of post-installed large diameter anchor systems. The investigation involves testing of 48 specimens, including four combined-anchor types (grout-plain, grout-grooved, epoxy-plain, and epoxy-grooved). Anchor bars with diameters 36 mm, 48 mm, 90 mm, 150 mm were chosen, and the selected embedment depths were 8, 10, 12 times the bar diameters. Results indicated that tensile capacity is related to the bar diameter, anchoring agent, bar surface type, and embedment depth. Based on the results and existing design models, a modified design equation is proposed. A comparison of test results with the results of modified equation shows that the modification provides a better estimation for the post-installed large diameter anchor systems. The modified equation can be applied to the design of anchoring reinforcement for engineering.