This paper studies the seismic performance of tall buildings with transfer girders or slab. These transfer systems are often used to transfer vertical and lateral loads from the upper superstructure to the lower substructure. Two case studies were analyzed using the response spectrum and pushover analysis methods. The analyses were carried out using ETABS computer software. The selected case studies have either transfer girders or transfer slab. Seismic response parameters such as; base shear, story shear distribution, bending moment distribution, top displacement, story drift, time period and response modification factor are obtained for each study case. Moreover, pushover analysis (POA) is done to evaluate the capacity of the existing building to resist the anticipated earthquake loads. The results of the studied cases indicated that, the base shear obtained using POA is about 65% to 83% of that calculated using the response spectrum. On the other hand, the base shear calculated using the response spectrum of Saudi building code (SBC 301) is considerably lower than that obtained using POA. Also, the response modification factor is very sensitive to both horizontal and vertical irregularity. |
