Which collapse pattern describes outer walls remaining intact while the upper floors or roof fail in the middle?

• A. U shaped
• B. Inverted V
• C. V shaped
• D. Box Collapse

Answer: (C)

Recognize how and where the structure fails. When the upper floors or roof give way in the middle while the outer walls stay standing, the debris falls inward and outward in a way that forms a V shape from above. The outer walls act like the two sides of the V, while the center drops, giving that distinctive V-shaped collapse pattern. This contrasts with other patterns: an inverted V would imply the failure lines form a peak at the top with the center rising rather than dropping; a U-shaped pattern involves three sides collapsing away from one side leaving a U-form; and a box collapse involves all four sides collapsing to create a box-like debris field.