چكيده به لاتين
Concrete and steel are materials which are used widely in construction industry. These two materials have widespread benefits and are the most important materials used in the structure of the building. Concrete is a material with high hardness, low price and considerable resistance against fire, and steel is a material with high ductility and strength and low weight and space. In structures especially tall structures, using only steel in construction of columns is non-economic. Furthermore, tall structures, which are only constructed using steel columns, usually have a relatively large lateral deformation. Also, these structures are highly vulnerable to fire. Using only concrete in the columns of tall buildings leads to the occupation of too much space especially in the lower classes and the weight of structure increases. Due to the brittleness of the concrete, the resulting structure has less ductility, and a resistance will be created in the structure against the seismic loads. Intelligent combination of these two materials and the use of their benefits can lead to cover any weakness and to promote the performance of the structure. The combination of these two materials leads to the creation of complex systems. To conduct this study, and to model this type of building system, OPENSEES software was used. The analysis method was as dynamic analysis- time history. First, the results were compared using an experimental model. Then, after validating the model, the final model was presented. Based on the obtained results, in short structures the earthquake behaviour is better if circular columns are used, while in high rises a better earthquake behaviour is seen using columns with elliptical cross-sections.
