Which type of collapse creates voids on the perimeters and occurs near the middle of the floor?

The correct answer is V-type collapse, which is characterized by the creation of voids along the perimeter of a building while the middle of the floor tends to sag or dip downward. This collapse pattern typically occurs when the load and structural support from the mid-section of the floor are compromised, resulting in a failure that creates these distinctive triangular voids.

In a V-type collapse, elements such as floor joists or beams may give way, leading to the middle of the floor sagging while the edges remain relatively intact for a short period. This behavior can pose significant risks to firefighters, as they may not anticipate the presence of void spaces where heat and smoke can accumulate. Understanding this collapse pattern is crucial for effective firefighting tactics as it informs strategies for search and rescue operations.

Other types of collapses, such as box-type, frame, and A-frame collapses, exhibit different characteristics and behavior under stress. A box-type collapse generally leads to more of an inward collapse without the distinct voids seen in a V-type collapse. A-frame collapse provides a different structural failure pattern, usually seen in structures with steep roofs, while a frame collapse affects the integrity of the structural frame itself. Recognizing the specific signs and risks associated with a V-type collapse