Thursday, December 18, 2008

Doppelmayr engineers now on site to investigate cause of Excalibur Gondola Tower collapse

Whistler Blackcomb, the BC Safety Authority and Doppelmayr directors are working around the clock to move forward on the investigation into Tuesday’s tower collapse on the Excalibur Gondola, and to restore public confidence in one of the world’s most sophisticated resort lift systems.
The cause of the tower failure was confirmed by early Wednesday morning, and was due to an extremely unusual situation called "ice-jacking". The structure of the tower is such that two parts are spliced together. Water had seeped into the lower section of the tower and turned to ice with the recent extreme cold temperatures. While extremely cold temperatures are not uncommon at a ski resort, the water had accumulated to a point whereby the pressure from the ice created a rupture that separated the two sections of the tower. The force of the ice expansion and the subsequent rupture has been estimated at 800 tonnes of pressure.
According to Doppelmayr and the BC Safety Authority, there is only one other known incident involving lift tower structural failure and ice-jacking. This incident took place at a USA ski resort in 2006.
"The towers are not normally designed to allow for any water penetration and so this failure is a very unusual situation", says Warren Sparks, senior vice president of Doppelmayr Canada. "Our attention now has shifted to understanding how this water penetration has happened and we have independent structural engineers reviewing the tower from Vancouver-based CWMM Consulting Engineers Ltd. The evidence found so far indicates a sudden rupture rather than a fatigue failure over an extended period".