Steel braced frame systems (SBFs) having high stiffness and high strength are commonly utilized due to their resistance to lateral seismic forces in regions with high seismicity. In this study, concentrically braced frames (CBFs) having different bracing configurations are used to obtain the significance of the pulse period associated with near-fault (NF) ground motion by time-history dynamic analysis. Besides, far-fault (FF) ground motions are also used to compare with NF ground motion results according to chancing bracing configurations. To achieve dynamic responses of steel frames with different concentric bracings under NF ground motions, which especially have small, medium, and long pulse periods, 3-story and 4-span CBFs having different bracing configurations were selected as an example. 4 FF and 12 NF ground motions having different pulse durations were chosen to evaluate the dynamic response of concentrically braced frames. The results showed that peak ground acceleration (PGA) could be identified as a key parameter that controls the response of braced frames under FF ground motions. In addition, the ratio of the pulse duration to the first mode period is the dominant parameter when this ratio is only greater than 1.0 under the NF ground motions.

Base isolation system with lead rubber bearing (LRB) is commonly used to prevent structure against to damage of earthquake. Design of LRB system is detailed in this study. The isolated building with LRB design according to Uniform Building Code (UBC-97) and fixed building were examined. The six-storey building with LRB and fixed building were modelled in SAP2000 with the same dynamic loads. The relative floor displacement and internal forces of the seismic isolated and fixed building are compared. In addition, transverse and longitudinal reinforcement of any axis of seismic isolated and fixed building are compared. Analyse results showed that effectiveness of using seismic isolation system on building. The weight of longitudinal and transverse reinforcement of isolated building is smaller than fixed building about 36%, 40% respectively.

Construction costs are increasing day by day. The importance of building the safest structures at the lowest cost is also increasing. For this purpose, it is necessary to design the structure in the best possible way without sacrificing safety. One way to ensure buildings are safe even during severe earthquakes is to include seismic isolation at the design stage. Judging by studies, seismic isolators are generally located at the lowest story of the building. However, the location of the seismic isolator on the lowest column has not been defined. In this study, the seismic isolator was located at the lower end and the top of the lowest story of the RC building to compare the effectiveness of its positioning. A high-damping rubber bearing (HDRB) was used as the seismic isolation device. Also, the effect of the absence of the diaphragm placed above the isolation level was investigated. As a result of the study, the necessary rebar of the RC building isolated at the top end of the column was less than 15% compared to the building isolated at the lower end of the columns for the beams. The base shear force of the building with seismic isolator located at the upper end of the column was 2.7% greater than that the building with the seismic isolator located at the lower end of the column.