Collapse of Prefabricated Floor Slabs in Houses

The collapse of prefabricated floor slabs in houses can be caused by various factors and often results in severe casualties. Details are as follows:

Causes of Collapse

• Waterlogging: In an incident where a prefabricated floor slab collapsed inside a house in Hubei, waterlogging was the direct cause. When the prefabricated slab is exposed to a waterlogged environment for an extended period, its internal structure may be damaged by water erosion, leading to a reduction in strength and ultimately an inability to bear the upper load, resulting in collapse.
• Improper Demolition Operations: The collapse accident in Dongwenquan Town, Banan District, Chongqing, was due to improper demolition sequence by the workers. Before the brick railings on the cantilever beam's outer balcony were fully removed, the workers proceeded to chisel and clean the cushion layer and slab joints of the second-floor prefabricated slab floor, reducing the load on the slab. As a result, the overturning moment outside the cantilever beam exceeded the anti-overturning moment inside, triggering the collapse of the prefabricated slab.
• House Aging and Renovation Issues: In the collapse accident in Longyuan Community, Datong Town, Suburban Tongling City, Anhui Province, the residential building was of brick-concrete prefabricated slab structure. Although it had undergone three old community renovation projects previously, the renovations may not have fully addressed the structural safety hazards caused by house aging, such as aging of the prefabricated slabs and loosening of connection parts, ultimately leading to the collapse.

Consequences of Collapse

The collapse of prefabricated floor slabs in houses often leads to severe casualties. In the Hubei incident, four people fell into the nearly 2-meter-deep basement water. Although they were rescued in time and uninjured, the situation was extremely critical. The Chongqing accident resulted in one death and three injuries, while the Tongling accident caused four deaths, with one person still undergoing intensive treatment. These accidents highlight the severe危害性 (hazardous nature, here translated as 'serious危害性' in the original Chinese context, but more naturally rendered as 'hazardous nature' in English) of the collapse of prefabricated floor slabs in houses, posing a significant threat to residents' lives and imposing a heavy burden on families and society.