Classification of the damage according to the type of structures
The level of damage in spatial trusses has also been classified into three different levels based on the type of structure:
Two layered spatial structures
Over a hundred two layered spatial structures composed of tube parts and standard connecting systems is available in areas stricken by earthquake. While there are just about 10 two-layered spatial structures which are seriously damages.
Different types of damage in these structures are squeezing of the support places and non-elastic buckling of parts close to the support places. The first type of damage normally has occurred in structures that are used to cover the space between two buildings. In these structures as a result of movements in the nearby buildings, they suffered from severe damages in the support places.