Load-Bearing Capacity of Prefabricated Floor Slab Houses

The load-bearing capacity of prefabricated floor slab houses has no fixed value and needs to be comprehensively judged based on the type, specifications, span, reinforcement, and load distribution of the floor slabs. The standard value of uniformly distributed live load for ordinary residential buildings is usually 200-350 kilograms per square meter. The specific analysis is as follows:

1. Load-Bearing Capacity of Different Types of Prefabricated Slabs

1. Concrete Hollow Slabs
   Commonly found in rural self-built houses and old residential areas, the standard uniformly distributed load is 200-250 kilograms per square meter. For example, a hollow slab that is 3.6 meters long and 0.6 meters wide (with an area of 2.16 square meters) has a total load-bearing capacity of approximately 432 kilograms when evenly distributed. Its load-bearing capacity is significantly affected by the span: a 2.4-meter span slab can reach 250 kilograms per square meter, while a slab with a span of more than 4.2 meters may drop to 150-180 kilograms per square meter.

2. Solid Prefabricated Slabs
   Mainly used in areas with relatively large loads such as kitchens and bathrooms, with a load-bearing capacity of 250-300 kilograms per square meter. High-quality solid slabs produced by large factories can have their load-bearing capacity increased to 300 kilograms per square meter due to sufficient reinforcement (such as 8-millimeter steel bars spaced 15 centimeters apart) and high concrete grades (C30 and above).

3. Prestressed Prefabricated Slabs
   By using high-strength steel wires for tensioning to generate prestress, they have stronger crack resistance and load-bearing capacity. Slabs with a span of less than 3 meters can have a load-bearing capacity of 300-400 kilograms per square meter; when the span is more than 4 meters, they can still maintain a load-bearing capacity of 250-300 kilograms per square meter.

2. Key Influencing Factors

1. Span and Thickness
   The shorter and thicker the prefabricated slab, the stronger its load-bearing capacity. For example, a 10-centimeter-thick slab has better load-bearing capacity than an 8-centimeter-thick one; for every 1-meter increase in span, the load-bearing capacity may decrease by 20%-30%.

2. Reinforcement Situation
   The thicker the diameter of the steel bars and the smaller the spacing (such as 8-millimeter steel bars spaced 15 centimeters apart), the better the load-bearing performance. Insufficient reinforcement can easily lead to cracks or deformation of the floor slab.

3. Load Type
   Concentrated loads (such as the stacking of heavy objects at a single point) are more dangerous than uniformly distributed loads. For example, for a floor slab with a uniformly distributed load of 200 kilograms per square meter, evenly spreading 200 kilograms of sand is safe, but placing a 300-kilogram safe may cause cracks.

3. Special Cases and Safety Recommendations

1. Special Cases
   Well-designed prefabricated floor slabs can have an overall load-bearing capacity of more than 500 kilograms per square meter, but it is necessary to avoid local concentrated loads exceeding the flexural or shear limits. For example, a 4-meter-long prefabricated slab generally cannot directly bear a load of 2 tons. It is necessary to reasonably design the positions of the supports, disperse the loads, and ensure that the load-bearing capacity of the supports does not exceed the limit values.

2. Safety Recommendations

   • Understand the load-bearing capacity of the floor slab to ensure that decoration and furniture placement meet the requirements.
   • Avoid local overloading. Heavy objects should be evenly distributed or placed close to load-bearing walls, beams, and columns.
   • Regularly check whether there are cracks or deformations in the floor slab.
   • When purchasing prefabricated slabs, be sure to check the factory certificates and test reports to ensure they meet national standards.