How did the floor collapse occur?

The floor collapse occurred suddenly, forming a lean-to collapse, which is characterized by a rapid failure of structural support resulting in one side of the structure falling while the other side remains somewhat intact. In a lean-to collapse, the affected portion of the floor may shift or tilt, creating a triangular configuration that can endanger individuals and equipment below.

This type of collapse can often be attributed to immediate stress factors, such as excessive weight or heat exposure from a fire, which compromises the integrity of the floor joists or beams. The sudden nature of the collapse can lead to serious consequences for those working in the vicinity, as it provides little warning or time to react.

Other options describe scenarios that are less likely to cause the type of collapse in question. While a gradual failure over time might lead to a collapse, it generally lacks the immediate impact of a sudden collapse. Similarly, a loud explosion is not characteristic of most structural failures unless accompanied by an external blast, and a gradual process causing minimal damage would not align with the sudden structural failure observed in this context.