Versailles Wedding Hall Disaster - Investigation

Investigation

An investigation of the event concluded that the event was not caused by a terrorist attack. This was based on the testimony provided by many of the wedding guests present in the building during the disaster. Witnesses reported seeing a dangerous sag in the floor moments before the collapse. An initial inquiry blamed the collapse on the Pal-Kal method of constructing light-weight coffered concrete floor systems. Further review pointed to a combination of two alternate causes.

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. Unfortunately, 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.

A few weeks before the collapse, the wedding hall owners decided to remove the partitions. With the load path eliminated, the floor above began to deflect (or sag) several inches. Generally, engineers design a structure to fail in a controlled, ductile manner so that occupants have ample warning that a collapse is imminent and can evacuate. The owners failed to recognize this and viewed the sagging floor primarily as a cosmetic problem. Their solution was to level the floor with additional grout and fill. However, their approach not only failed to provide additional structural capacity, it also inadvertently introduced a new and significant dead load at the weakened area.

During the wedding event in 2001, this significantly overstressed floor section failed, resulting in the catastrophe. The engineer Eli Ron, inventor of the Pal-Kal method of construction, was arrested and subsequently indicted in August 2002 on the charge of manslaughter. Notably, Ron had not engaged in any part of the design or construction, but had sold proprietary elements necessary for construction that were installed in a deficient manner.