Damage to Concrete Prefabricated Houses

Common causes and countermeasures for the "pulling damage" (fracture or damage) of concrete prefabricated houses are as follows:

I. Common Causes

1. Overloading
   The design load-bearing capacity of prefabricated slabs is limited. If heavy objects (such as building materials, furniture, etc.) are temporarily stacked or if the concentrated load is too large, brittle fracture can easily occur. For example, in the 2023 accident in Zhong County, Chongqing, the second-floor slab fractured due to an overload exceeding the design value, resulting in casualties.

2. Material and Construction Quality Defects

   • Poor-quality materials: Thin steel bar diameters, insufficient cement grades, or improper concrete mix ratios can significantly reduce the strength of prefabricated slabs.
   • Construction defects: Defects such as through-cracks, honeycombing, and pitting in prefabricated slabs, or insufficient curing leading to early shrinkage cracks, can shorten the service life.

3. Foundation Settlement or Temperature Changes

   • Uneven foundation settlement: If the foundation of the house is uneven or not compacted, it may cause uneven stress on the prefabricated slabs, leading to cracks.
   • Thermal stress: Thermal expansion and contraction, along with drying shrinkage, can generate internal stress in the prefabricated slabs, which, if accumulated over time, may cause slab joint cracking or slab fracture.

4. Long-term Aging and Over-service Life
   Prefabricated slab houses built in the last century typically have a design life of about 40 years. After over-service, problems such as steel bar corrosion and concrete carbonation can reduce structural safety and increase the risk of fracture.

5. Installation Issues
   If the slab joints are not properly grouted or if reliable connections (such as steel bar anchoring) are not established during the assembly of prefabricated slabs, the overall stability can be reduced, making the house prone to collapse under earthquake or external forces.

II. Countermeasures

1. Avoid overloading: Do not concentrate heavy objects in prefabricated slab houses, especially avoid stacking large building materials or equipment on the second floor and above.
2. Regular inspections: Focus on checking for cracks or deformations in slab joints and load-bearing components (such as beams and columns), and address potential hazards promptly.
3. Professional assessment and reinforcement: For houses that have exceeded their service life or have quality defects, commission a professional institution to conduct a structural safety assessment and reinforce them as necessary by methods such as粘贴碳纤维布 (pasting carbon fiber sheets) or adding supports.
4. Improve usage conditions: For houses with severe foundation settlement, the foundation can be reinforced by grouting; for temperature cracks, flexible sealing materials can be used to treat slab joints.

Tip: The safety of prefabricated slab houses is closely related to material quality, construction quality, and usage maintenance. During daily use, it is essential to strictly comply with design specifications and avoid人为破坏 (human-induced damage) to structural stability.