a Little time? At the end of text there is a summary.
The huge amounts of snow in the South of Bavaria and in Austria, are a burden. Not only for the people who live in those villages as in the Berchtesgadener Land. Also, for the roofs of the houses. The roof of a warehouse collapsed in Inzell in Bavaria. And in Weidenberg a cowshed collapsed at a length of about 20 meters.
The piled-up snow amounts to the authorities for days. Bavaria’s Prime Minister Markus Söder have already said on Saturday: “The biggest challenge for the next few days will be the roofs load.”
Roped Bundeswehr soldiers, Federal police officers or employees of the Federal Agency for Technical relief work on the roofs and get rid of the snow. According to the district of Berchtesgadener Land and more than 1800 emergency responders cleared up Monday nearly 500 roofs. Buildings such as kindergartens and gymnasiums, which have important functions for the public infrastructure, as well as such objects, in which people or animals were in danger, have preference.
in fact, buildings collapse under snow load. Only in the past year the roof of a sport gave in to the hall in the Czech Republic. And also the collapse of the ice rink of Bad Reichenhall in 2006, was triggered by snow. How dangerous is the white splendor for roof structures?
such As avalanches, Extreme weather conditions such As avalanches are created, and what makes them so dangerous.
In the case of the static planning of buildings, engineers consider the different types of snow loads that have to withstand a roof. There are standard values in the applicable regional building codes which must be adhered to in the calculations.
The values are not the same everywhere, they depend on the geographical location of a building and the height of the terrain. Basically, a roof in a Region must, in the statistically a lot of snow, more enduring, it hardly snows.
Germany is divided into five different snow load zones, they are created on the basis of local measurement. The highest Zone 3, for example, the Alps, the Bavarian forest, the Thuringian forest, the ore mountains, or of the resin – i.e., regions where a lot of snow can fall.
map of snow load zones source: DIN EN 1991-1-3/NA:2010-12 | snow load zones according to administrative boundaries 2015-02-13 | LTB Mecklenburg-Vorpommern 2018-09-30 | http://www.gadm.org/download | http://srtm.csi.cgiar.org/SELECTION/inputCoord.asp snow load zone 1 1* 1a 2 2* 2a 3 3* N/A
is The lowest Zone, large parts of Northern Germany, the middle Rhine valley, or the includes of the Rhine plain. A roof in Bad Reichenhall has to withstand a load of 232 kg per square meter, in Nuremberg, only about 65 kilograms, writes the building surveyor Klaus Schweikl. For very extreme events as they occur statistically rarely, are not designed the roofs but in principle.
is allowed to be As much snow on a roof, even a flat rate of say. First of all, the roof form plays a role. Also walls or Gables may have an impact. Because there can accumulate snow because of the Wind there has bubbles of snow-blind education. Therefore, a client is already in the planning phase, the responsibility, if the new building is of an old border and on the neighboring roof, therefore, the wind conditions change – this applies to check.
the evaluation of the high-speed load is Complicated on a roof, but for another reason. Because snow does not equal snow. Loose powder snow is much lighter than wet snow, such differences caused by the different weather conditions in the atmosphere at the time of the snowfall. Basically, the snow is heavier, the higher the water content.
As a result of very different weights for the snow. New snow weighs about 100 kilograms per cubic meter. With a wet snow of about 500 kg can be achieved. And ice is about 900 kg per cubic meter.
the roof of the road master in the Bavarian town of Wolfratshausen, for example, the visited Markus Söder recently, was at the time of his visit, with up to 90 kilograms per square meter of snow-burdened. Is designed it up to 115 kilos per square meter . Therefore, the snow was here as a precaution from the roof geschüppt.
Different layers, different weight
of Course, a Snow cover is not heavy, if you is some time and set, they reduced their volume. But the thaw is threatening to rain, sucked in the Snow like a sponge full of water. Then the weight changes.
for a long time, snow is rarely a homogeneous mass but consists of different layers, all of which have different weight. Brings clarity, therefore, only a measurement in a tube is a kind of core of the entire snow layer is taken. Then the snow density, freezing degree and water content information on each of the layers and their weight.
Basically, the owner of a building is by the way responsible for checking the risk of a snow load. Instructions for the estimation of the Snow cover on a roof, the Bavarian land, among others, are office for the environment. However, the Federal Agency for Technical relief has a snow load measuring units can be obtained from the use of forces in case of an emergency. In difficult cases, the house should instruct owners prefer to have experts for the clearance of a roof and not even up there climbing around.
A disaster such as the collapse of the ice rink of Bad Reichenhall, in the snow-rich Winter of 2005/2006 cannot be excluded, is threatening in all likelihood currently. Because after the extreme winter and the collapse of the significantly the use of the wrong glue was to blame, has improved the prognosis of dangerous snow events. So experts can respond earlier than in the past, and locally better discharge planning measures.
Also with the Review of the older buildings was begun. The Federal Ministry of transport, building and urban development adopted as consequence of the accident a few weeks later a Directive, preventive, annual condition inspection of structures requires, in order to detect risks in a timely manner. Such tests are carried out in the case of bridges already for a long time on a regular basis.
somewhere in the concrete or moisture gets in, the long-term Problem, to a RÜV-examination (Directive on the Monitoring of traffic safety of buildings of the Federal government) that detect and document. However, this Directive is mandatory only for buildings of the Federal government. Although you apply now even some local authorities. However, it is not enough to criticize some of the surveyors. Owners of private factories make use of the procedure mandatory, in order to clarify the conservation status of their building. The roof of the camp hall in Inzell is sure to be the last thing broke.
Summary: The snow load was threatening many of the roofs in Bavaria and Austria. Although the structures are designed for loads depending on the Region, on different types of snow. But the actual weight is often difficult to determine because snow usually consists of different heavy layers, which may only assess experts.