Anchor fasteners are used for securing structures to concrete, brick, and stone. Mechanical anchors include wedge (expansion), drop-in, and ceiling anchors. Chemical anchors, such as ampoule and injection (resin + metal), are used for critical fastenings in cracked concrete. A wedge anchor consists of a bolt with a cone and an expansion sleeve; tightening the nut wedges it in the hole. Pull-out load capacity: M8 — 10–15 kN, M16 — 35–50 kN (in C20/25 concrete). Chemical anchors consist of a two-component resin (epoxy, vinyl ester, polyester) + a stud, with a calculated load capacity 20–50% higher than mechanical anchors. Certification: ETA (European Technical Approval) is mandatory for critical anchorages (seismic, fire). Leading brands are Hilti, Fischer, MKT. Packaging includes boxes and cartridges (for chemical anchors). Chemical anchors vs. mechanical anchors: Chemical anchors work in cracked concrete, hollow materials, and near edges—where mechanical anchors are unreliable. Curing time depends on temperature: at +5°C — up to 2 hours; at +20°C — 20–45 minutes. Load calculations are based on ETA or the manufacturer's technical guide with safety factors.