Which type of collapse happens when one side of a floor or ceiling collapses next to a load-bearing wall?

• A. Frame
• B. Lean-To Collapse
• C. V-Shape
• D. Cantilever Collapse

Answer: (B)

A lean-to collapse occurs when one side of a floor or ceiling fails next to a load-bearing wall. In this scenario, the wall continues to support the remaining portion, acting like a hinge, so the unsupported side drops while the portion near the wall stays in place. The result is a leaning, or “lean-to,” shape where the floor/ceiling tilts toward the wall. This geometry is distinct from a frame collapse (where the entire structural frame fails), a V-shape collapse (where sections fall away toward a central point to form a V), or a cantilever collapse (where an overhanging portion beyond its support gives way).