# A.2.2: Additional Information on Loads

Karamba3D expects all force definitions to be specified in kilonewtons (kN). On Earth, a mass of 1,000 kg corresponds to a weight force of approximately 10 kN. A more precise value is 9.81 kN, but 10 kN is typically accurate enough for most calculations. **Table A.2.2.1** lists the specific weights of common materials, while **Table A.2.2.2** provides rough estimates for various loads. These values should be used as guidelines, as certain loads—such as snow loads—can vary significantly based on geographic location.

For loads distributed along lines or over areas, these can be approximated using point loads. To do this, estimate the area or length of influence for each node and multiply it by the given load value. The **Mesh-Load** component (refer to section 3.2.1) can be used to automate this process for surface loads.

## Table A.2.2.1: Specific weights of some building materials

| Type of material    | $$kN/m^3$$ |
| ------------------- | ---------- |
| reinforced concrete | 25.0       |
| glass               | 25.0       |
| steel               | 78.5       |
| aluminum            | 27.0       |
| fir wood            | 3.2        |
| snow loose          | 1.2        |
| snow wet            | 9.0        |
| water               | 10.0       |

## Table A.2.2.2: Loads for typical scenarios

| Type                            | $$kN/m^2$$ |
| ------------------------------- | ---------- |
| live load in dwellings          | 3.0        |
| live load in offices            | 4.0        |
| snow on horizontal plane        | 1.0        |
| cars on parking lot (no trucks) | 2.5        |
| trucks on bridge                | 16.7       |


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