What collapse pattern occurs when a wall fails and a floor or roof section drops completely on one side while the opposite end remains supported?

• A. Pancake collapse
• B. Lean to collapse pattern
• C. V-shaped collapse
• D. Uniform collapse

Answer: (B)

This question tests your ability to recognize collapse geometries based on how debris moves when a failure occurs. When a wall gives way and the floor or roof on that side drops completely while the opposite end stays supported, the structure tilts toward the failed side, producing a leaning appearance. That leaning, one-sided drop is the hallmark of a lean-to collapse: the intact side acts as a fulcrum and the rest of the structure “tips” away from it.

Pancake collapse would show floors dropping straight down in stacked layers, not a single-sided tilt. V-shaped collapse involves debris converging toward the center or apex, creating a V pattern rather than a single leaned direction. Uniform collapse means the entire structure subsides evenly with no pronounced lean.