OSHA ASME
1926.1402(a)(1)
“Ground conditions” means the ability of the ground to support the equipment (including slope, compaction, and firmness
1926.1402(b)
The equipment must not be assembled or used unless ground conditions are firm, drained, and graded to a sufficient extent so that, in conjunction (if necessary) with the use of supporting materials, the equipment manufacturer’s specifications for adequate support and degree of level of the equipment are met. The requirement for the ground to be drained does not apply to marshes/wetlands.
1926.1402(a)(2)
“Supporting materials” means blocking, mats, cribbing, marsh buggies (in marshes/wetlands), or similar supporting materials or devices.
For those who do not work in construction:
ASME B30.5-3.2.1.5 (i) regarding mobile and locomotive cranes states that blocking under outrigger floats, when required, shall meet the following requirements: (1) sufficient strength to prevent crushing, bending or shear failure (2) such thickness,width and length as to completely support the float, transmit the load to the supporting surface and prevent shifting, toppling or excessive settlement under the load