initially, the side of the building that failed was designed to be a two-story structure, while the other side was designed to be three stories. late in the construction process, it was decided that both sides of the building should be equal heights, and a third story was added to the shorter side. however, the live load due to occupancy is typically much greater than the design load for a roof. as a result, the structure supporting the new third story was subjected to much greater loading than was originally anticipated. the effect of this error was somewhat mitigated by the construction of partitions on the floor below, which helped redistribute the excess load well such that no damage was incurred.