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ÖgeEarthquake performance and project budget comparison of a conventional building and a seismically isolated building(ITU Graduate School, 2021)In the structural design process, various design methods are used all around the world. Seismic isolation is a relatively new method for designing earthquake-resistant structures in comparison with the conventional design approaches. Basically, all the design methodologies specified in the codes and specifications aim to protect life safety of the residents in the building by resisting the forces that may be occured by earthquakes. The energy released by the earthquake must be absorbed by structural elements before the structural failure occurs. While the structures that are designed according to conventional design approaches dissipate the earthquake energy by the help of the possible damages that may be occurred in its structural elements, the aim of base isolation usage is to diminish the effect of the forces that are transmitted to the structure from the ground. Therefore, in base-isolated buildings, the structural elements would be less damaged, and the structure may not lose its functionality after being exposed to different earthquake excitations. Seismic isolation devices are placed into the base of a structure to enhance the ability of energy dissipation. The energy is absorbed by the displacement of the isolation level. This reduces the earthquake effects that the building experiences. In this study, a five-storey structure is chosen to be analyzed from both earthquake safety and cost perspectives. Time history analysis are carried out with SAP 2000 software. The building's width and height are chosen as 40 m and 15 m, in a respective way. The buildings that have same width and height are modelled for two cases. One with fixed base and the other with base-isolation. Time History analysis are performed for both cases by using the same earthquake record to determine the earthquake performance of the buildings. In Case I, the fixed-base building is used. The earthquake performance of the building is obtained by the help of time history analysis. Secondly, a base isolated building is modeled and analyzed. In addition to the comparison of earthquake performance, this study evaluates the cost of these two cases. With no doubt during an earthquake the life safety is the primary concern however financial situation must also be taken into account during the design process. Cost estimation plays a prominent role for financial project budget. It aims to maintain the project with the available resourses. These resources, of course, have limitations since every project have its own budget and time-limit. The method of design has a great impact on the project budget of the building. Design method affects not only the construction cost of project, but also service-life of the project. The costs of both conventional and seismically isolated buildings are calculated. Then, the seismically isolated and conventional buildings are compared in terms of their seismic performance and the project budget.Finally, the result of seismic performance and the cost benefit are presented and discussed according to findings of the analysis. It is obtained from this thesis that, although the initial construction cost of the seismically isolated structure is obviously more than the conventional building, eventually in a possible earthquake scenario seismic isolation may provide financial advantage over the conventional building case.