Pal Kal floor system blamed for deaths of 23 people at a wedding.

An Israeli court has sentenced the engineer who developed the “Pal Kal” building method, after he was convicted of gross negligence in the deaths of 23 people and the injury of hundreds of others in the May 24, 2001, collapse of a wedding hall in Jerusalem.

Eli Ron was given a four-year prison term. Two other engineers, Shimon Kaufman and Dan Sheffer, who designed the building, were given 22-month sentences and a third engineer, Uri Pesach, an assistant to the inventor, a six-month term.

In December, the Jerusalem District Court convicted all four of negligence and sabotage by negligence. The collapse of the Versailles hall was related to use of a controversial flooring technique that was eventually rejected by the Israel Standards Institute in 1996 (ENR 6/4/01 p. 14). Pal Kal was invented in the mid-1980s by Ron, former chief structural engineer for Israel’s Public Works Authority, as a cost-saving technique. In place of corrugated sheet metal installed between concrete layers to add strength, the system uses corrugated sheet-metal boxes as the stress support system. But reports indicate the boxes can end up “floating” between the concrete layers if something goes wrong with the pour.

The presiding judge in the case, Moshe Gal, wrote in his ruling that the Versailles disaster is one of the worst ever caused by negligence in Israel’s history. He noted that Ron aggressively marketed his construction method and gave false presentations even though he was fully aware it had not been approved and did not meet regulations.

The Israel Contractors Association estimates there are still up to 3 million sq meters built using Pal Kal. These include the Bank of Israel in Jerusalem, shopping malls and university buildings. The country’s building authorities have checked many of the buildings in recent years. In some instances, floors were reinforced by adding  slabs.

Ron says he will appeal the sentence to the Supreme Court on grounds that the collapse was not caused by Pal Kal. The state prosecutor also expressed dissatisfaction with the sentences and said it may appeal their leniency.