Abstract: At 7:30 a.m. on September 8, 2015, an employee was trying to add horizontal bracing under the floor instead of vertical bracing. The U channel was being attached to the underside of the floor purlins from a step ladder. An elevated floor was switch from wood to concrete without changing the prints. The prints called for a wood floor. The floor purlins were to be on 12 inch centers but they were installed on 16 inch centers. The elevated steel floor and concrete collapsed from the weight of the concrete and fell onto the employee. The employee was was crushed and killed from being covered by steel and concrete.