Which of the following is NOT a listed collapse pattern?

• A. Lean-to
• B. V shape
• C. Wedge
• D. Cantilever

Answer: (C)

Recognizing the standard collapse pattern categories used in US&R work helps you quickly interpret debris and plan stabilization. In the common lists, lean-to describes a collapse where one side remains supported and the opposite side drops, producing a leaning wall. A V shape occurs when two large blocks slide away from each other, leaving a narrow apex. Cantilever involves a portion of the structure still attached on one end while the other end collapses outward. Wedge is not one of these named patterns in the typical catalog of listed collapse patterns, so it isn’t considered a listed pattern.