What best describes a drop-in anchor?

• A. A bolt that requires a nut
• B. A threaded-sleeve anchor placed into a drilled hole and driven in with a hammer or setting tool.
• C. A plastic anchor used for light loads
• D. A rivet with a split sleeve used with a rivet gun

Answer: (B)

Drop-in anchors are a type of expansion anchor used in concrete. They are installed by drilling a hole, dropping the anchor into the hole, and then driving the interior setting plug with a hammer or setting tool. This action expands the outer sleeve against the hole walls, creating a secure threaded receptacle for a bolt. Once expanded, a bolt can be threaded into the anchor to fasten components. This matches the description of a threaded-sleeve anchor placed into a drilled hole and driven in with a hammer or setting tool. The other options describe different fasteners: a bolt that requires a nut is a through-bolt; a plastic anchor for light loads is not a drop-in expansion anchor for concrete; a rivet with a split sleeve is a rivet-type fastener, not a drop-in anchor.