Time history analysis for high rise braced and unbraced steel structures

The fact that our country is on an active earthquake zone and in our country in recent years due to damage and loss of life caused by the earthquakes it has been understood that the design is required to be resistant to dynamic actions. In the present thesis study of linear dynamic analysis of high rise steel buildings, considering seismic magnitude of 7.4 representing Istanbul–Gölcük earthquake is carried out and seismic responses of 30 and 50 story building are studied with the purpose of designing the most effective steel structure for resisting the lateral loads caused by earthquakes. The buildings under consideration is modeled with the help of SAP2000 software and is optimally redesigned with cross bracing system. The results of the study shows similar variations pattern in seismic responses such as base shear and story displacements with buildings and the cross braced structure gives smaller lateral deformations than un-braced type of structure. So, the cross-braced system is considered safer. From the study, it is recommended that analysis of high-rise storied steel building using time history method is necessary to ensure reliable behaviour against earthquake loading. The time history analysis can depict the whole process of the variation of the dynamic response of the structure with time.