Prefabricated Panel House Collapse Event

The main causes of the collapse of prefabricated panel houses include structural aging, overloading, construction quality defects, and external triggers (such as heavy rainfall, gas leaks, etc.). A detailed analysis is as follows:

1. Structural Aging and Material Performance Degradation

Prefabricated panel houses were mostly built in the 1980s-1990s, using brick-concrete prefabricated panel structures. The floor slabs and walls are connected through prefabricated components, resulting in poor overall integrity. Over time, concrete carbonation and steel bar corrosion lead to a decrease in load-bearing capacity, making them prone to brittle fracture under earthquakes or external impacts. For example, in the collapse incident of an old building in Shijiazhuang, the house was built in the 1980s. Although the exterior walls were painted during the renovation, the core structures such as the floor slabs were not reinforced, resulting in poor overall integrity and weak earthquake resistance. Ultimately, it collapsed due to a suspected gas leak-induced explosion.

2. Overloading and Improper Use

The design load-bearing capacity of prefabricated panels is limited. Long-term overloading or temporary stacking of heavy objects may cause fractures. In the house collapse accident in Zhong County, Chongqing, the floor slab on the second floor fractured and fell due to the temporary stacking of goods, exceeding the design load, resulting in 2 deaths and 3 injuries. Such accidents indicate that users' neglect of the load-bearing capacity of the house structure is a direct trigger.

3. Construction Quality Defects and Inadequate Renovation

Some prefabricated panel houses have construction defects, such as loose component connections and insufficient mortar strength, which exacerbate the risk of aging. In addition, if renovation projects only focus on exterior renovation (such as painting exterior walls) and do not carry out substantial reinforcement of structures such as floor slabs and beams and columns, safety cannot be improved. Before the collapse of the building in Tongling Community, although it had undergone renovation, only the exterior walls were renovated, and issues such as foundation soaking and structural aging were not resolved. Heavy rainfall became the "last straw" that crushed the house.

4. External Triggers: Natural Disasters and Accidents

Natural disasters such as heavy rainfall and earthquakes may damage the foundation or structural stability of houses. In the Tongling incident, experts initially analyzed that heavy rainfall soaked the foundation, causing soil softening and triggering the collapse of the brick-concrete prefabricated panel structure. In addition, explosions caused by gas leaks (such as the Shijiazhuang incident) or waterlogging (such as the floor collapse in Hubei) may also directly cause local or overall collapses.