February 14, 2006

Roof construction questioned in spate of fatal collapses in Europe

WARSAW, Poland

Snow-laden roofs buckling in central Europe have buried 78 people beneath tonnes of steel and concrete this winter, raising troubling questions about safety standards and pressures on builders to use lighter materials to cut costs.

The search for answers has focused on whether snow that has been unusually wet this season, and therefore heavier, is exposing flawed design standards for flat metal roofs.

The collapse of an exhibition hall in the Polish city of Katowice killed at least 63 people Jan. 28. In Germany on Jan. 2, 15 people, most of them children on a school holiday, died when the roof of a skating rink fell in the Bavarian town of Bad Reichenhall. In at least three other collapses, there were narrow escapes.

More wet snow fell last week in Bavaria, and soldiers and firefighters were enlisted to help clear roofs.

Marian Gizejowski, an expert in building structures at Warsaw University of Technology, said roof design has changed in recent years.

“Roofs are made now lighter and cheaper, from lighter materials and the calculations are done by computers. But there should be limited trust in computer calculations that are only a tool in the whole process.”

The Bad Reichenhall rink was built in 1972 with wooden beams. But many of the other roofs that collapsed recently were flat metal structures such as the hall in Katowice, which was built in 2000.

Gizejowski said this winter’s heavy wet snow has been particularly hard on roofs, exposing flaws that had not been previously noticed.

“It is hard to say now what the exact reason was in Katowice, whether faulty structure or poor materials were used that added to the weather factor,” he said.

Kazimierz Szulborski, a Polish expert on construction standards, said the heavy snow was exposing weaknesses in structures that used lighter materials to save costs.

“Poland is a poor nation and we are expected to build light structures,” said Szulborski, head of construction mechanics at Warsaw University of Technology’s architecture school. “In the past 10 to 15 years, the tendency prevailed to build fast and at low cost, and to make profit fast.”

After the Katowice tragedy, state construction authorities and building owners examined all buildings with large flat roofs, and closed 248 structures.

Criminal investigations are underway into the disasters in Katowice. In the German collapse, experts have suggested the weight of snow on the roof was only a trigger.

Associated Press

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