In the present report, we have clarified the desirable position of a shear key, the shearing strength of shear-key and the bond resistance of side surface of a bore hole and the effect of strength of filling cement mortar on tensile strength from the pull-out test under the conditions varing the embedding length of anchor bolts, the positions of a shear-key, the amount of filling cement mortar, the strength of filling cement mortar and the size of diameter of a bore hole. Also we have obtained the equivalent bond strength of compressive failure zone near the anchor bolt head, and have shown the formula of estimating the pull-out strength of concrete anchors in each failure types.
