Collapse of Prefabricated Panel Houses

The collapse of prefabricated panel houses is primarily caused by structural defects, external triggers, and improper human operations.

1. Structural Defects: Insufficient Integrity and Earthquake Resistance
Prefabricated panel houses often adopt brick-concrete structures, with prefabricated hollow slabs forming the floor through splicing and installation. This structure has an inherent defect of poor integrity, with weak connections between components, making it prone to "brittle failure"—where local failure prevents effective stress transfer, leading to chain collapses. For example, in the collapse of the old building in Shijiazhuang Railway 55 Dormitory, despite renovations in 2020, only the exterior walls were refurbished, while the floor remained prefabricated hollow slabs, leaving the integrity unimproved and ultimately causing a collapse due to local failure. Additionally, prefabricated panel structures have weak earthquake resistance and are prone to instability and collapse under external forces such as earthquakes or foundation settlement.

2. External Triggers: Environmental Factors and Overloading
External factors are significant triggers for the collapse of prefabricated panel houses. Heavy rain soaking the foundation can lead to soil softening and reduced bearing capacity, causing house tilting or collapse. In the collapse of a building in Tongling Community, experts initially identified heavy rain soaking the foundation as one of the triggers. Overloading is also a common cause; for instance, in the prefabricated panel fracture incident in Zhong County, the second-floor slab collapsed due to temporary stacking of goods exceeding its load-bearing capacity. Furthermore, long-term weathering, corrosion, or uneven foundation settlement can weaken structural stability.

3. Improper Human Operations: Construction and Renovation Risks
Improper human operations can directly cause collapses. Incorrect demolition sequence is a typical issue; for example, in the collapse incident in Banana East Hot Spring, workers failed to follow the principle of "top-down, layer-by-layer demolition" during dangerous building renovations, leading to the collapse of the second-floor prefabricated panel slab cushion. Non-standard renovations are equally dangerous; some renovations focus only on exterior refurbishment without reinforcing the structure, such as the "paint-only renovation" in the Shijiazhuang incident, which concealed隐患 (hidden dangers) like slab aging and loose connections. Additionally, illegal additions or changes in building use (such as converting residential buildings into warehouses) can also trigger accidents due to increased loads or altered structural stress.