Bad+Reichenhall,+Germany+-+Ice+Rink

toc =** Bad Reichenhall, Germany - Ice Rink (January 2, 2006) **= By Deborah Dudenhoefer, Karlie Heffner, Gina Rossi, and Chandra Swope Bad Reichenhall Town Hall (Wikimedia Commons)

**Introduction**
On January 2, 2006, the roof of Bad Reichenhall Ice Rink collapsed due to a 30cm-40cm snow fall on New Years Day. Of the 50 people inside at the time, 34 people were injured, while 15 died in the collapse. After review of the collapse, it was determined that water damage in the roof was ignored causing the timber roof design to weaken. The architect, H-J. Schmidt and Partner (Munich), and engineer, Timber Construction Contractor, and surveyor were tired for manslaughter. While the architect and surveyor were acquitted, the engineer had an 18 month suspended sentence.

The 75x48m building was constructed in 1972, with a timber roof construction using traverse box girders at 7.5m on center with 4m cantilevers on each end.(Goetz, 1989) The roof rafters failed from prior water damage, while the building was still approved for accommodation. Reports of leaks in the roof had been made prior to the collapse, formal complaints had been made due to sights of buckets placed to catch water from leaks. Mayor Wolfgang Heitmeier argued against immediate renovation because he felt the water was from condensation and the leaks did not affect the structural integrity of the building. The town council chose to invest in projects such as spas and the fitness center instead. On the day of the collapse, hockey practice was canceled due to safety concerns, however the hall remained open to the public. After public skating on Monday, city officials ordered the rink to be closed because snow was continuing to fall, but the rink was reopened and deemed safe for occupation on Tuesday. The disaster could have been avoided if the hall had been evacuated early Monday afternoon when the roof strength had begun to be questioned. After the collapse, Mayor Heitmeier made a statement saying that the structural stability of the roof was not in question. The amount of snow on the roof was not uncommon for the region where 100cm can fall in the span of a day.(Kleinert,2006)

**Causes of Failure**
Water damage in wood causes serious weakness in structural members. This environmental moisture content with in structures leads to 21% of building failures, with human error being the main cause of these failures.(Dietsch, 2010) With owners and managers of property not maintaining roofs and supports, this neglect endangers the people using the structure. "Correct and timely maintenance of the building is an essential prerequisite towards a consistent structural performance over its lifetime. In many cases, this requirement was not followed, leading to increasing risk of failure and decreasing reliability of the structure."(Dietsch, 2010) (Dietsch, 2010)

**Prevention**
Roof collapses can occur for several reasons. Those reasons include an incorrect roof live load design, problems with the installation of the roof steel, if the roof drains or downspouts become blocked or frozen which prevents drainage, if additional dead load is added to the roof overtime, or if there is an inbalance of snow load on the roof.(Zurich, 2003)
 * Why do roof collapses occur?**
 * Snow Load Based on Accumulation Depth ||  ||   ||
 * = Snow Depth on Roof (ft.) ||= Dry Snow (lbs./sq. ft.) ||= In Between Snow (lbs./sq. ft.) ||= Wet Snow (lbs./sq. ft.) ||
 * = 1 ||= 3 ||= 12 ||= 21 ||
 * = 2 ||= 6.5 ||= 24 ||= 42 ||
 * = 3 ||= 9.5 ||= 36 ||= 62 ||
 * = 4 ||= 12.5 ||= 48 ||= 83 ||
 * = 5 ||= 15.5 ||= 60 ||= 104 ||
 * ||  ||   ||> (Zurich, 2003) ||

Buildings generally exhibit signs that the roof is in distress and action should be taken. These signs include visual deformation or sagging in the roof steel, cracked or split wood members, sprinklers that are pushed down below ceiling tiles, doors that pop open, doors or windows that are difficult to open, bowed utility pipes, bowed conduits attached at ceiling, and creaking, cracking, or popping sounds.(Zurich, 2003)
 * Warning Signs**

Many roof collapses can be prevented. Before and during a snow or rain event roof drains should be cleaned of ice and accumulated debris. Immediately inspect the roof after major winter storms where more than 8 inches of now or 2 inches of rain has fallen in 24 hours. Gutters and downspouts should be kept clean. Heat-tracing in gutters and downspouts should be provided. The bottom of downspouts should also be truncated 2 feet above grade to ensure they do not freeze at the bottom. Do not plow or shovel snow against downspouts so that proper drainage can occur. Snow accumulations from the roof should be removed when 50% of the design strength is reached.(Zurich, 2003)
 * Actions to Prevent Collapse**

Roof failures are generally caused by either a flaw in structural design or lack of maintenance (Zurich, 2003). Similar to the collapse of the Ice Rink in Germany, there was a failure in the timber roof structure of a gymnasium at Nettlehorst School in Chicago, IL. The bottom chord of a timber roof truss fractured, leading to the partial collapse of the roof in January of 2002. This failure was due to a miscalculation of stress on the structure due to increased loading (Duntemann, 2008). Another similar building failure was the roof collapse of the Seimen's Super Arena. A truss line fell under a snow load of 50 kg/m. Engineers claimed that the failure was caused by failed joints because of badly manufactured connections. There are also many residential cases of roof failures that could have been avoided through better construction and upkeep of the building (Hansson, 2005). @Rosemont Horizon Arena, is a wooden roof failure similar in structure, but caused be other circumstances. Katowice Trade Hall Roof Collapse (Wikimedia commons)
 * Similar Cases**

Conclusion/Lessons Learned
In this particular case, the failure was not due to design, but because of a failure to maintain the structure. The snow load did not exceed the amount which the building was designed to support which places the blame for the collapse of the neglected water damage within the roof rafters. Poor maintenance and poor decisions made by the authorities involved, made the collapse into a disaster. The collapse made apparent that the owner/authorized person is responsible for the maintenance of their building. The timely and correct maintenance of a building is necessary to maintain consistent structural performance over the buildings lifetime. Many times this responsibility is not observed and causes minor to major problems with the structure, such was the case with the Bad Reichenhall ice rink.

This article briefly explains the effects of snow loads on structures and how these loads can cause buildings to collapse.
 * O'Rourke, Micheal (November 2008). "Structural Collapse from Snow Loads." STRUCTURE Magazine. .(February 8, 2010).**

This journal explains the snowstorm that caused a snow load on the ice rink in Bad Reichenhall which initiated to the collapse of the water weakened timber roof.
 * Tornado and Storm Research Organization (2006). "The International Journal of Meteorology." Vol.31, Issue 305-314. (98).**

This article explains warning signs and steps to take to prevent roof collapse due to snow load.
 * Zurich. (November 2003). "Snow Loading Roof Collapse." Zurich Services Corporation. <****www.cwpeteragency.com/zurich/images/nowlading.pdf>.(March 23, 2010)**