Failures of Roofs under Snow Load: Causes and Reliability Analysis

Collapses of a number of roofs in Europe during the winter 2005/2006 initiated discussions concerning reliability of the roofs exposed to snow loads. Presented overview of extensive investigations of structural failures is focused on causes and consequences of failures. Main observed causes may be subdivided into human errors and insufficient code provisions. Collapses developed from local failures particularly in cases of insufficiently robust structures. Probabilistic reliability analysis reveals that the model for snow loads in the Eurocodes should be modified. Obtained experiences provide valuable background information for future revision of current standards and for forensic assessments of failures of structures exposed to snow loads.