Abstract: Employee #1 was sitting on a beam behind the owner holding two drift pins (spud wrenches) on each side of another beam as the owner guided that beam into position and onto the spud wrenches. After removing both nuts from the bolts and closing it up against the web of the column, Employee #1 reached over to put the nuts onto the bolts. The beam they were sitting on suddenly started to drop down into the ground, while the other end remained bolted to the horizontal I-beam. Employee #1 suffered a leg fracture from the vertical beam falling on him. Employee #2 suffered a sprained knee when he jumped into the machine room pit.