Unstable Columns Cause Joists to Collapse; One Dead, Three Injured

Case 1: Five ironworkers were distributing 90-foot-long open web bar joists on a building under construction. The bar joists were supported by vertical columns spaced 30 feet apart. The steel columns were not framed in at least two directions, and the bar joists were not field-bolted to the vertical columns to prevent collapse. The bar joists shifted, causing the vertical columns to lean. This resulted in the entire section of columns and open web bar joists to collapse. Two employees rode the iron down. One was killed and one received serious injuries.  Case 2: Two employees had just finished setting and bolting a 60-foot steel truss atop two 30-foot steel columns. As the crane load line was disconnected, a high gust of wind blew over the truss and columns. One employee rode the truss to within approximately 12 feet of ground level when he fell off, striking his face and nose on the ground. The other employee rode the truss all the way to the ground and was thrown into the webbing when the truss bounced on impact. He suffered a sprained right ankle. The whole truss and column configuration then fell into another erected truss/column set, knocking it down as well. As allowed by the steel erection standards in place at the time, neither employee was tied off to a safety device.