The anchorage in the concrete is produced by the foot of the anchor creating a wrenching cone. The anchorage resistance depends on:
• The concrete resistance (fck)
• The length of the foot anchor (L)
• Distances to the edge of the concrete (TN)
• Distances between each anchor (TN)
The larger the wrenching cone, the higher the anchorage is resistant. It is at its maximum when the distance between fixing centers of the anchors is greater than 6 times the anchoring depth (hef) and the distance to the edge of the concrete is greater than 3 times hef.