BC+Place+Stadium

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Anthony Dallessandro, Marissa Levash, Veronica Patrick, Penelope Peralta

Abstract
BC Place Stadium is located in Vancouver, Canada and was the first multi-purpose domed arena in Canada. Ground for the stadium was broken in April of 1981 and the stadium was completed on June 19th of 1983. It is the largest air supported stadium in the world. On January 5th, 2007 wind and sleet damage led to a hole in the stadium's teflon roof on a west side triangle panel. At approximately 12:49 pm the roof was intentionally deflated which allowed rain and snow to pour into the stadium. No one was injured due to the damage.

Figure 1: Obtained from Investigation Report: BC Place Roof Deflation Incident of January 5

The disaster was technically a structural failure, but it can be blamed on human carelessness. The roof was re-inflated after the snow was removed and the hole in the teflon roof repaired.

Plans for a retractable roof are in the works and are expected to be added to the current stadium in 2012.

**K** ey Words
Vancouver, Air Supported, Sleet Damage, Teflon Roof, Deflated

 It took from April 1981 to June 1983 to construct the BC Place Stadium in Vancouver, BC, Canada. The architecture firm of studio Phillips Barrett constructed the 247,000 sq. ft. stadium and equipped it to seat 60,000 people. In total the construction cost was $126,000,000 (Emporis 2009, 1)

The stadium was built in anticipation for the World’s Fair Expo starting on May 2, 1986. During this, the Prince and Princess of Wales welcomed the world to the expo (thecanadianencyclopedia.com). Starting in 1983 the stadium’s main occupant was and still is the Canadian Football League’s BC Lions. Another minor user was the North American Soccer League’s Vancouver Whitecaps (1983-1984). The stadium was also built in hopes of attracting a Major League baseball team; however, this has not yet occurred. As a multifunctional structure BC Place can house a wide spectrum of activities ranging from sporting events to rock concerts and royal visits. On average BC Place holds events 200 days out of the year bringing in around $63 million annually. (bcplace.com)

The roof of the stadium ushered in lots of attention. Constructed out of 10 acres of fiberglass woven fabric that’s 1/30th of an inch with two layers of it set at four feet apart, the roof is surprisingly strong. It allows 20% natural light to illuminate the inside area and uses 16 jet engine fans to make sure the inside pressure is greater than that of the outside. With a span of 640 ft x 774 ft it is the world’s largest air-supported roof. (bcplace.com ). Figure 1 shows an interior view of the fiberglass air-supported roof.

Comments about the roof being in bad shape were made in May prior to the incident. Member of the Legislative Assembly Guy Gentner stated that "B.C. Place Stadium is close to its end. The roof is ready to fall down, according to the service plan. Its anticipated lifespan is coming to an end. Could the minister tell us when the life-cycle replacement is due on the roof at B.C. Place Stadium?" (cbc.ca) Gentner was informed that the roof, if maintained adequately, was intended to last another 15-20 years; however less than a year later Gentner’s suspicions, with the help of poor weather, were proven true. By the time of the collapse (about 24 years after the end of construction) the roof fabric was nearly 40% below nominal strength (Bilben 2008, 1).

On January 4, 2007, the day before the collapse, workers reported that the day started off like a normal shift. However, a warning came in of “near freezing outside temp., watch for snow” later that night (Hughes 2007, 10). Around 4:30 AM on the day of the collapse the first major snow condition alarm came in and a roof sensor sent out a moisture alert. Immediately a CR operator went outside to check the conditions but reported not seeing any snow accumulating on the roof. The operator called his supervisors and after being unable to contact them he called the Director of Operations who said he would come in around 6:30 AM. When the Director arrived there was a 2 inch accumulation of snow/slush on the ground and it was noticeably cooler inside the stadium than usual but nothing was done about it. Around 10:30 AM a CR operator checked a roof camera for snow accumulation and reported none. However, it was unrealized at the time that the camera was only showing an area in which the snow had been removed by a fan and that the surrounding roof was thoroughly covered with frozen material that would soon cause a major crisis. (Hughes 2007)

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Causes
The main cause of the BC Place stadium roof failure was not structural errors, but human error due to lack of training. If proper procedures had been followed and the accumulation of snow had not gone unnoticed than the failure would not have occurred.

Failure to Increase Heat
In total there were five automatic snow melt warnings sounding off to alert the staff of the falling snow. However, these warnings went unnoticed. Heating of the stadium prior to snow fall along with increasing the pressure of the air inflated roof would have prevented the overload on the roof.

Avalanche Due to Pressure Excursion
During the attempted recovery of the faulty west triangle panel there was no assessment for the best course of action. Due to lack of crisis training for the employees in the control room the decision was made to increase the overall pressure of the stadium. This caused the pressure in the stadium to rapidly rise from 250 PA to 520 PA and than back down. The mass of snow, water, and ice rose rapidly when the roof was at a pressure of 520 PA and slid towards the hole in the west triangle panel. The 8,000 to 11,000 pounds of mass caused a failure at the weakest point in the roof fabric at 12:46 pm. As seen in Figure 2a, only the top of Vancity Office Building is showing. As opposed to figure 2a, 2b, after the tear, the roof is visibly lower as now the top five floors of the office building are exposed.

The torn panel can be seen here. []

Figure 2a Obtained from Investigation Report: BC Place Roof Deflation Incident of January 5 Figure 2b Obtained from Investigation Report: BC Place Roof Deflation Incident of January 5

**Prevention**
Although the prevention of the BC Dome collapse cannot be pin pointed at a definite structural flaw, it could have certainly been avoided with the lack of human fault, pre-existing damage, and poor weather conditions. Guy Genter, a member for the New Democrat MLA for Delta North, raised questions of BC Place’s roof in the legislature May of 2006 saying, “"B.C. Place Stadium is close to its end. The roof is ready to fall down, according to the service plan. Its anticipated lifespan is coming to an end.” The response he received was that the already twenty five year old roof was expected to last another fifteen to twenty years if properly maintained. As the 50 mm of wet snow and 6 mm of rain fell onto the roof that fateful day, maintenance workers were supposed to be in charge of clearing the build of water on roof either by increasing the temperature or internal pressure of the stadium. Geiger Engineers reports states that a faster response to unfavorable weather conditions such as “increasing building pressure sooner so that rain and snow could not have collected to the extent that it did” could have eliminated the collapse. (BC Place Stadium Dome Collapse Preventable) (B.C. Place probes dome collapse)

**Lessons Learned From Event**
Through thorough analysis of the failure, the ineffective policies implemented, procedures and proper training were all the root causes of this event. The major lesson learned from this catastrophic event was that one cannot ignore the procedures that were supposed to be executed when there was snow piled on top of the structure. The fact regarding that heat is expensive is no excuse as to why the heat should not have been turned on. This laid back approach to the situation caused the incident when it could have been prevented. There was also a lack of correct training and comprehension involved that was tied in correlation to the roof support system.

**Future** Prevention
There are 5 main changes that are highly recommended to be put into effect in order to abstain from this failure occurring again. The first one includes setting up a “No Snow Accumulation” policy that will inform and be implemented immediately. This would be the main goal of the stadium to make sure no snow accumulates. The second would comprise of completing and independent audit of Stadium Operations. This would heavily focus on the proper procedures, policies and training needed so that next time a situation like this occurs, it will be handled correctly. Furthermore, the next main change would be to as soon as possible make sure that a qualified person or agency carries out a detailed assessment of the materials and seams in the roof. This will aid in making sure that the roof will last as long as possible. Additionally, a consultation with a professional who has a wide knowledge about these types of roof systems needs to improve and modernize the support control systems that will include a control observance room. This is where workers will be able to observe the roof and make sure a crisis does not occur again. Lastly, an independent external audit by the Occupational Health & Safety program needs to be thoroughly completed by the facility and make sure these recommendations are put into operation so as to prevent these disasters from occurring again.

Conclusion
Lessons were learned from the BC Place roof collapse. Better preparation and monitoring must be observed by all employees who are engaged in such massive buildings. Further training and enforcement of procedures is necessary. The future of the BC Place Stadium includes plans of adding a retractable roof. This would help prevent anymore catastrophic failures for the previously stated reasons, but adds much more room for error. Structural errors may be prevalent in the new retractable roof.