Which collapse pattern involves exterior walls collapsing simultaneously, causing the roof and upper floors to collapse on top of each other?

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

Answer: (A)

This question is about recognizing a vertical, stack-like collapse pattern. Pancake collapse occurs when the upper floors and the roof give way and collapse straight down onto the lower levels, often with the exterior walls falling in as part of the same, compact pile. The result is a layered, “pile of pancakes” where debris from each floor sits directly atop the one below, with little to no horizontal spreading. This matches the description of exterior walls failing simultaneously and the roof and upper floors collapsing on top of each other.

This differs from other patterns: a V-shape collapse involves walls giving way inwards to form two wings and a central void, a lean-to collapse leans to one side with partial support, and a cantilever collapse features an overhanging portion supported on one side while the rest drops away.