Uniformly distributed load
Also called UDL
A load treated as spread evenly across an area rather than concentrated at a single point — the loading from a general work platform or from stored materials over a floor or ground area, for example. UDLs generally produce lower local bearing pressures than an equivalent point load, which is why point loads such as outrigger feet are usually the governing case for crane mat design.
In practice
A UDL is a modelling convenience, and it is only valid while the load really is spread. Materials stacked on a working platform, a laydown area or a slab are usually assessed this way; a machine standing on it is not. The two cases are checked separately, and a surface signed off for one has not been signed off for the other.
Where this comes from: Standard structural and temporary works usage; the distinction from a point load is the one that governs mat sizing.
Where it matters on site
Most disputes about whether ground or a slab “takes the crane” come from a UDL figure being quoted for a point-loaded case. When someone offers a capacity in kN/m² for a floor or a working platform, the useful next question is what area that figure is averaged over, and whether an outrigger foot bearing on a fraction of a square metre was ever in scope.