Load Capacity of Floor Slabs in Prefabricated Slab Houses

In ordinary residential buildings, prefabricated slabs can typically bear a load of about 200 kilograms per square meter. However, the specific load-bearing capacity needs to be comprehensively evaluated based on the grade of the prefabricated slab, structural conditions, and load distribution.

I. Grade Classification of Load-Bearing Capacity for Prefabricated Slabs
According to the 'Building Structural Load Code' and practical engineering applications, the load-bearing capacity of prefabricated slabs is divided into three grades:

1. Grade I Slabs: These have the lowest load-bearing capacity, supporting only 100 kilograms per square meter. They are suitable for non-residential spaces or temporary buildings with extremely low load requirements.
2. Grade II Slabs: With a load-bearing capacity of 200 kilograms per square meter, these are the standard grade used in most ordinary residential buildings, meeting basic needs such as furniture placement and human activity.
3. Grade IV Slabs: These have the highest load-bearing capacity, reaching up to 400 kilograms per square meter. They are mostly used in old factory buildings or industrial buildings with high load requirements, and are rarely used in residential buildings.

II. Key Factors Affecting Load-Bearing Capacity

1. Material and Structural Parameters:
   • Concrete Grade: The higher the grade, the stronger the compressive strength of the concrete, thereby enhancing the load-bearing capacity.
   • Reinforcement Model: The diameter and quantity of steel bars directly affect the tensile properties of the prefabricated slab. Reasonable reinforcement can enhance overall stability.
   • Slab Thickness: A 10-centimeter-thick prefabricated slab is sturdier than a thinner one, and increasing the thickness can significantly improve the load-bearing capacity.
2. Room Span and Support Conditions:
   • The larger the room span, the greater the bending moment in the middle of the prefabricated slab, reducing its load-bearing capacity.
   • Adding beam supports during construction can disperse the load, effectively enhancing the load-bearing capacity and avoiding local stress concentration.
3. Load Distribution Method:
   • The 200-kilogram load standard is based on the assumption of uniform distribution. If the weight is concentrated on a small area (such as stacking heavy objects at a single point), even if the total weight does not exceed the standard, local stress may be too high, leading to floor cracking.

III. Potential Risks of Prefabricated Slab Houses
It should be noted that most prefabricated slab houses were built in the early days and have the following drawbacks:

1. Short Service Life: Long-term use may lead to concrete carbonation and steel bar corrosion, reducing structural safety.
2. Poor Seismic Performance: With weak integrity, they are prone to component detachment or overall collapse during earthquakes.
3. Limited Functionality: They have insufficient thermal and sound insulation properties, and their spatial layout is difficult to meet modern living needs.

Recommendation: If renovations or the addition of heavy objects (such as fish tanks or large furniture) are required, a professional institution should be commissioned to test the actual load-bearing capacity of the prefabricated slabs to avoid overloading.