Collapse of Prefabricated Floor Slabs in Buildings

The collapse of prefabricated floor slabs in buildings is primarily caused by overloading or structural defects, with typical cases demonstrating sudden and cascading damage.

Overloading as a Direct Cause

Prefabricated floor slabs are prefabricated components designed with specific load-bearing capacities. If the actual load exceeds the design value, brittle fractures can easily occur. For example, in the 2024 collapse incident in Zhong County, Chongqing, the second-floor slab was used as a cargo warehouse, with temporary stacking loads far exceeding the slab's capacity, leading to slab fracture and collapse, resulting in 2 deaths and 3 injuries. Such cases indicate that overloading (e.g., stacking heavy objects, converting to warehouses) can directly damage the slab structure, especially in older buildings where the prefabricated slabs have further degraded in load-bearing capacity due to long-term aging, increasing the risk.

Structural Defects and Aging Exacerbate Risks

Prefabricated buildings often adopt a construction method with brick walls bearing the load and prefabricated hollow floor slabs, resulting in poor overall integrity and weak seismic resistance. In the 2026 collapse incident in Xinhua District, Shijiazhuang, a four-story prefabricated brick-concrete building collapsed due to a gas explosion triggered by a leak, but the root cause lay in structural defects within the building itself: weak connections between the prefabricated slabs and brick walls, which easily led to cascading collapses upon local damage. Additionally, prefabricated buildings constructed in the 1980s have significantly reduced structural strength due to material aging (e.g., concrete carbonation, steel reinforcement corrosion), and may collapse due to insufficient stability even without external impact.

Preventive Measures Need to be Targeted

To address load issues, heavy objects should be avoided from being stacked on prefabricated floor slabs or converted into high-load functional areas (e.g., warehouses), and regular inspections should be conducted for cracks or deformations in the slabs. For structural defects, older prefabricated buildings require reinforcement and renovation, such as adding ring beams and structural columns to enhance overall integrity, or using new materials like carbon fiber sheets to improve slab load-bearing capacity. Meanwhile, gas safety inspections and seismic reinforcement should be carried out simultaneously to reduce the probability of collapse caused by the叠加 (superposition) of multiple risks.