AZ stadium collapse caused by fierce winds, not solar panels

The partial collapse of the AFAS Stadion roof earlier this month was caused by the downward force of heavy winds. The stadium, home of Alkmaar-based football club AZ, will now undergo a renovation in which roughly 75 percent of the roof will be renovated or replaced.

The team will play all of its upcoming Europa League matches at Cars Jeans Stadion, the home venue for ADO Den Haag. The sites for most of the team's upcoming Eredivisie matches, and any possible KNVB Cup games, have not been announced.

Welds that were possibly too thin and not strong enough were part of the problem that led to the August 10 incident, the team and engineering consultancy firm Royal HaskoningDHV said, according to AD. Of the heavy storm that brought 100 kilometer per hour wind gusts to Noord-Holland that day, the firm's director Erik Middelkoop said, "The roof was not designed for that."

An initial investigation by the Dutch Safety Board (OVV) also determined that the welds had failed. An inspection of the portion of the roof that was still standing found two construction fractures and two more suspicious areas, the OVV said on August 16.

Hundreds of solar panels installed on the roof years after the stadium was built were reportedly unrelated to the partial collapse. A former Alkmaar alderman also alleged that safety recommendations were ignored when the stadium was erected.

Demolition work was already underway at AFAS Stadium. It was not clear how long the stadium roof rebuild would take.

"We want to get to a safe situation as quickly as possible," said Robert Eenhoorn, general director of AZ Alkmaar.

So far, home AZ matches have been played in Den Haag and De Grolsch Veste, where FC Twente plays in Enschede.