Which type of collapse describes a floor system that has failed with only one end still supported?

The type of collapse characterized by a floor system that has failed with only one end still supported is known as a lean-to-floor collapse. In this scenario, the floor gives way at one end while remaining attached or supported at the other. This type of collapse typically creates a slanted surface, resembling a lean-to structure, where the unsupported end drops downward, while the supported end is elevated. This can pose significant risks during a fire scenario, as the remaining support can lead to a precarious situation for firefighters or occupants.

In contrast, free span collapses occur when a structure loses support from all sides, usually resulting in a complete drop without any remaining structural integrity. Overhang collapses involve portions of a structure that extend beyond their supports, often leading to a failure where those overhanging sections collapse downwards. Tip over collapses typically involve vertical elements like walls or columns that fall over rather than a horizontal floor system. Understanding these distinctions in collapse types is critical for assessing risks and developing strategies for safe interventions in fire situations.