Increased Snow Loads and Wind Actions on Existing Buildings: Reliability of the Norwegian Building Stock

Results from an investigation of snow loads and wind actions on 20 existing buildings in Norway are presented. The objective has been to investigate to what extent existing buildings meet current regulatory requirements relating to safety against collapse owing to snow loads or wind actions. Eighteen buildings have a utilization ratio of more than 1.0 under current regulations. The new design rules have led to most of the buildings investigated having reduced safety against collapse owing to snow loads and greater safety against collapse owing to wind actions than the regulations now demand. The investigation indicates too low reliability for a considerable number of buildings according to current building regulations when evaluating the possible consequences of the conclusions in a national perspective. Scenarios for future climate change indicate both increased winter precipitation and increased temperatures, and thus changing the snow loads on roofs. Wind scenarios for the decades to come indicate an increase in frequencies of strong winds in areas also exposed today. Thus, the future reliability of the buildings in these areas could decrease.