Prefabricated Slab House Collapse Accident

Prefabricated slab house collapse accidents are usually caused by factors such as structural aging, overloading, or extreme weather. The following analyzes the causes and lessons learned from specific cases:

1. Structural aging and lack of maintenance are important contributing factors Take the building collapse accident in a residential area in Tongling, Anhui, on May 27, 2024, as an example. The house involved was a brick-concrete prefabricated slab structure built in 2001. The victim had reported housing safety hazards through the government mailbox three years prior, but no timely action was taken. Prefabricated slab houses, due to their early construction dates, may have issues such as material aging, rusting of connection joints, or wall cracks. If they lack professional inspection and reinforcement for a long time, they are prone to foundation softening and structural instability under external forces such as heavy rain. In addition, the Tongling Meteorological Station had continuously issued strong convective and heavy rain warnings before. The heavy rain soaking the foundation may have weakened the soil's bearing capacity, further exacerbating the risk of house tilting.

2. Overloading directly leads to local collapses In the prefabricated slab fracture accident in a house in Zhong County, Chongqing, on April 11, 2024, the second-floor slab fractured and fell due to the temporary stacking of goods exceeding its designed load-bearing capacity. Prefabricated slabs are prefabricated components, and their spans, reinforcement, and concrete strength are all designed according to specific loads. If the use is changed without authorization (such as converting a residence into a warehouse) or heavy objects are stacked in a concentrated manner, fractures can be triggered by local stress concentration. Such accidents mostly occur on the ground floor or middle floors because the upper-floor loads are transferred to the lower floors through the prefabricated slabs, and overloading can easily create a domino effect.

3. Extreme weather and construction quality pose叠加 (combined) risks In the Tongling accident, although heavy rain was the direct cause, the construction quality of the house was also questionable. For prefabricated slab houses, it is crucial to strictly ensure the connection strength between slabs and between slabs and walls. If tie bars are not installed as required or the joint filling is not dense during construction, rainwater may seep into the structure along the gaps, accelerating steel bar corrosion and concrete carbonation. In addition, improper foundation treatment (such as inadequate compaction or poor drainage) can amplify the impact of rainwater, leading to uneven settlement and ultimately causing a complete collapse.

4. Prevention and response recommendations

• Regular inspections: Conduct structural safety assessments of old prefabricated slab houses, focusing on connection joints, foundations, and walls.
• Load control: Avoid unauthorized changes in house use or overloading. Goods should be stacked evenly.
• Enhanced drainage: Clear the roof and surrounding drainage systems to prevent water from seeping into the structure.
• Emergency response: Evacuate people from dangerous areas before extreme weather events. After a collapse, prioritize the use of life detectors and small equipment for rescue to avoid secondary injuries.

The collapse of prefabricated slab houses is often caused by a combination of multiple factors, and it is necessary to strengthen management throughout the entire chain of design, construction, use, and maintenance.