Disclosed is a base assembly for supporting a crane pedestal. The base assembly comprises four base units, each having a first end and a second end, and each base unit being of an L-shape with an outside beveled corner. Fastening devices connect each base unit at their first and second end to respective first and second ends of another of the four base units. The four base units are dimensioned so that, when connected by said fastening devices, they form an octagonal-shaped base structure. The four base units are also dimensioned to support four pads that each rest on a face of each unit adjacent to its beveled corner when the four base units are assembled in the octagonal-shaped base structure. Also disclosed is a method for assembling a base assembly for supporting a crane pedestal and a fastening device for connecting the ends of two units together.