Abstract: At approximately 4:40 p.m. on August 14, 1989, at the intersection of South Salisbury and Salisbury streets in Raleigh, NC, a Grove 35-ton 100-ft-capacity truck crane overturned. The crane tipped over, causing the boom to rapidly descend into a construction site. The crane tipped over as a direct result of losing an inboard supporting outrigger through a weak area of the sidewalk, upon which the outrigger had been placed on an empty electrical transformer vault which had been back filled directly beneath the sidewalk area. The sidewalk section had apparently been weakened due to settling of the fill and scaling of the concrete cap. No injuries or property damage resulted from the incident non-compliance of applicable standards or safe work practices were not factors.