ACI Adhesive Anchor Installer Certification Practice Exam

How should the hole be drilled in accordance with standard practices unless specified otherwise?

1. Diagonal to the concrete

2. Perpendicular to the concrete

3. Parallel to the surface

4. At an angle of 45 degrees

The correct answer is: Perpendicular to the concrete

The proper drilling technique for adhesive anchors is to drill the hole perpendicular to the concrete surface. This orientation ensures that the adhesive anchor can achieve maximum holding strength and effectiveness by utilizing the full anchor diameter to bond with the concrete. Drilling perpendicular minimizes potential issues such as stress concentrations that can occur if the anchor is not seated properly, thus ensuring that the load is distributed evenly along the anchor and the surrounding concrete. In cases where the hole is not drilled perpendicular, such as at an angle or diagonally, the performance and reliability of the adhesive anchor can be compromised. Additionally, incorrect angles could lead to misalignment of the anchor, reducing its effectiveness under load, which is critical in construction applications where safety and performance are paramount. This makes drilling perpendicular the standard practice unless specific project requirements dictate otherwise.