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# Types of Collapses There are five generally recognized types of collapse: 1. V-shape 2. A-frame 3. Supported lean-to 4. Unsupported lean-to, also called cantilever 5. Pancake Several of the styles are likely to occur in specific classes of construction and often create their own particular st...

# Types of Collapses There are five generally recognized types of collapse: 1. V-shape 2. A-frame 3. Supported lean-to 4. Unsupported lean-to, also called cantilever 5. Pancake Several of the styles are likely to occur in specific classes of construction and often create their own particular style of void. If you can recognize the class of construction involved, you should be able to predict the possible types of collapse, the likely location of void spaces, and where you will most often locate surviving victims. ## V-shaped Collapses V-shaped collapses usually occur in Class 3 or 5 buildings having wooden floor joists when these joists are either overloaded, have a center support removed, or are burned away under load (fig. 22-28). The outer edges of the joists remain supported at the exterior walls while the center portion collapses. In this case, the walls and floors above usually remain intact, although any floors below may collapse because of the impact of the floors above. The shape of the collapse produces two voids on the sides of the debris, both of which must be searched. Victims on the collapsing floor, not in the vicinity of the collapse, will be thrown toward the center along with all the loose debris. Victims directly below the collapse will have the least chance of survival, while those along the perimeters will have the greatest (fig. 22-29).