A 29-year-old worker for a water tank company was killed when the partially assembled water tower he was working on was struck by a falling portable tower crane. The man was part of a three-man crew that reconditions and relocates used water towers, this one intended for a small rural Iowa community. An independent crane company was hired to erect supports for the water tower and lift the tank into its final position. This company erected its portable tower crane adjacent to the new foundations for the water tower, as close as possible. After hoisting the tank and while swinging it into position, with just a few feet to go, the rear crane outrigger facing the water tower slipped between cribbing timbers and sank into the ground. The entire tower crane fell towards the water tower, smashing everything in its path. The victim was sitting on a horizontal strut of the water tower base, approximately 80 feet in the air, preparing to adjust and tighten bracing rods once the tank was in position. Two other workers were injured, another member of the tank crew, who was positioned inside the ladder cage for the water tower, and the operator of the crane, who was sitting inside the control box of the crane 120 feet above the ground. Recommendations based on our investigation are as follows: 1. Crane owners and operators should ensure that cranes are properly set up with the outrigger pads supported by firm stable footing. 2. Crane set-ups should be closely observed during lifting operations to detect instability caused by changing load and ground conditions. 3. Prior to crane operations, construction companies utilizing crane services as well as the crane owners and operators should evaluate the soil bearing capacity at the lift site to ensure that crane equipment and procedures are compatible with site conditions.
Region-7; Accident-analysis; Accident-prevention; Accidents; Injuries; Injury-prevention; Traumatic-injuries; Work-operations; Work-analysis; Work-areas; Work-performance; Work-practices; Safety-education; Safety-equipment; Safety-measures; Safety-monitoring; Protective-measures; Construction; Construction-industry; Construction-workers; Construction-equipment; Equipment-operators; Equipment-reliability