Collapse of Concrete Prefabricated Houses

The reasons for the collapse of concrete prefabricated houses mainly include safety hazards, uneven quality, load-bearing issues, structural defects, and unauthorized extensions.

1. Safety Hazards
   Concrete prefabricated houses inherently have serious safety hazards, with relatively poor structural stability. Even a minor earthquake can cause connection joints to loosen or components to fracture due to vibrations, leading to house collapse. The seismic performance of such houses is significantly lower than that of cast-in-place structures, especially in areas with complex geological conditions or frequent earthquakes, where the risks are even higher.

2. Uneven Quality
   There are significant quality differences among prefabricated concrete panels on the market, with a high proportion of inferior products. Some products use low-quality concrete or steel bars, such as steel bars that are too thin, severely corroded, or even replaced with iron wires, resulting in insufficient structural strength. For example, in the collapse incident of a restaurant in Linfen, Shanxi, the diameter of the steel bars in the prefabricated panels was less than that of a little finger and heavily rusted, directly reducing the house's load-bearing capacity.

3. Load-Bearing Issues
   Prefabricated panels have a defined service life and load-bearing limit. Long-term natural aging, house modifications, overloading (such as stacking heavy objects), or vibrations from adjacent construction can all cause the prefabricated panels to crack or fracture. The house collapse incident in Zhong County in 2024 was caused by excessive temporary loads stacked on the second floor, exceeding the load-bearing capacity of the prefabricated panels and triggering brittle fracture.

4. Structural Defects
   Prefabricated panels are assembled structures with gaps between panels, presenting significant differences compared to cast-in-place panels:

• Poor sound insulation: Insufficient thickness and the presence of long circular holes in the middle result in strong sound penetration;
• Common water leakage: Gaps are prone to water seepage during the rainy season, corroding internal steel bars;
• Weak connections: Some manufacturers reduce costs by using single-layer steel bars or iron wires instead of frames, further weakening structural stability.

5. Unauthorized Extensions
   Some residents, in an attempt to expand their living space, directly add floors or rooms to existing houses, overloading the foundation and load-bearing structures. For example, the restaurant in Linfen, Shanxi, underwent multiple extensions and ultimately collapsed entirely due to insufficient load-bearing capacity of the second-floor prefabricated panel roof. Such behavior severely disrupts the original mechanical balance of the house and is a typical safety hazard.