Load-bearing/Load - what does it really mean?

[Kirre2021]

How does the load-bearing capacity of a floor work if we assume 200kg/sqm? What does that mean in practice for an ordinary layman?

Let's say a room of 10sqm is loaded with 200kg/sqm, i.e., a total of 2 tons distributed across the entire area. We are then at the theoretical maximum weight of the floor.

If we then load the same area with 3000kg (3 tons), what happens? Do the beams break and everything collapses, or is it about the beams bending beyond the tolerance according to building codes? For example, the beams sag 3cm instead of 2cm.

 

[Lennart12]

Hello,

If the floor structure is designed for 200 kg/m² and if the floor had a 100% utilization rate at the time of design, it will theoretically fail if this load is exceeded. However, it is more likely that there will be greater deformation with a smaller overload.

There are safety margins built into the materials; the materials can often withstand more than what is permitted by the building code to account for in design. Additionally, it is usually the characteristic load that is referred to when someone states how much a floor is designed to bear. For example, residential floors are typically designed for 200 kg/m² from variable loads (people, furniture, etc.), but this load is then multiplied by 1.5 during design, thus also adding a 50% safety margin.