【正文】 fety level in accordance with Table 2. In other words, the intention is to achieve a more uniform safety level for buildings that have the same reliability class even if they are built in different places, and also to obtain different safety levels for structures classified in different reliability classes. A thorough description of the historical development of design loads for wind actions and snow loads is presented by Meloysund et al.(2004).Selection Criteria and MethodologyLimits of Use The consequences of a collapse are greater in buildings in which many people are present than in buildings with few people. A collapse in public buildings such as sports halls, and the like has. Therefore, greater consequences than, for example, in storage facilities in which it is less probable that people will be present. This is also apparent from the reliability approach set out in numbers in Table 2 in which, under current rules, more stringent requirements are imposed on structures whose collapse may have major consequences.Material Use and Geometry For light roofs, the specific weight is open low pared to the snow load that the roof is required to withstand. If the snow load exceeds the design value, the load has increased virtually the same percentage as the snow load. If the specific weight had been high, the percentage increase would have been much smaller. Lightweight structures are, therefore, more vulnerable to an increase in snow load above the load for which the structure is designed than heavy structures. In other words, heavy structures have greater builtin safety when the snow load increases beyond the load that structure is designed to withstand. Another selection criterion is the maximum span of a building. The consequences of a collapse in buildings with large spans are usually great. A number of types of construction may be sensitive to unbalanced loads. When the structures are being cleared of snow, this may in the worst case make the stresses in the structure larger than before the snow clearance started. There are many examples of snow clearing leading to the collapse of structures. It is, therefore, important to know whether the structure can carry the unbalanced load that arises during snow clearance.Year of Construction, Loads, and Geographical Location Design loads on buildings have changed considerably in the period from 1949 to today. The year of construction may, therefore, tell something about the building’s safety level. In general, older buildings in highsnowfall areas may have a lower safety with respect to snow loads than newer buildings. The difference in safety level with respect to wind action is probably somewhat less. The safety level is probably affected mostly in areas that are heavily exposed to the environmental loads, when snow loads and wind actions in the regulation are increased from general loads that have applied to the entire country to differentiated loads that are adjusted to the actual environmental load variation in Norway. Increased wind actions, therefore, probably have the greatest consequences for coastal areas from northwest Norway northward. Locally roughness of terrain and topography and wind action are also important for the snow loads that the building experiences.Construction Process Prefabricated structures are often imported. It has been claimed that design calculations do not always meet the design rules set out in Norwegian codes and that many structures have been designed for relatively small snow loads pared to Norwegian requirements. Structures have been imported from countries such as Denmark that are designed for snow loads well below those required in Norway.Selected Buildings Based on the assessments above, 20 buildings were selected Table 3 lists the municipality in which the buildings were selected, the building type, and the requirement that currently applies to characteristic snow load on the ground and to the reference wind velocity. As shown in Table 3, attempts have been made to keep the selected buildings as anonymous as possible. Problems in obtaining the necessary documentation implied that an investigation of only one building was conducted in two of the municipalities, while this was extended to three buildings in two other municipalities. Three of the buildings were constructed in the period before 1970, eight were built in the period 197079, and nine were built in the period after 1979. This implies that the loads are determined by the 1949 building regulations for three of the buildings, by NS 3052 for the buildings, and by NS 3479 for nine of the buildings.Project Documentation Investigation and Field Study Calculation models, loads, forces, and solutions used when the buildings were constructed have been investigated. The forces in the structure were then determined in accordance with new load requirements, and the capacities checked in accordance with new load requirements. In light of these analyses, the structure’s utilization ratio has been determined in accordance with new calculation rules, and the need for reinforcement assessed. On site, whether the structures have defects or deficiencies that are not apparent from the project documentation of whether or not the construction was in accordance with the documentation, and whether or not there were weaknesses in the structure owing to reduced durability or due to reconstruction.ResultsGeometry and Material Data External dimensions, maximum spans, and the material of the main loadbearing structures are shown in Table 3. The building’s external dimensions are quoted as width, length, height, and roof slope. The height indicates the cornice height for buildings with other roof shapes. Additions or extensions that are not included in the assessments have not been included in the dimensions. As is apparent from the values in the table, the buildings selected can be characterized as mediumsized bu