1. Establish a non-isolated structure：A non-isolated structure of a twin-tower shear-wall structures with an enlarged basement is established in ETABS. The structure consists of 15 layers, each with a height of 3m, resulting in a total height of 45m. The bottom part of the enlarged basement comprises of two floors, with a total measurement of 6m, while the upper tower section includes 13 floors with a height of 39m. The enlarged basement spans over an area of 93m in length and 26.1m in width. It adopts a frame structure for its exterior and utilizes shear walls for the tower portion, which measures 30.5m long and 10.1m wide.
2. Using response spectrum method: Let the fortification intensity = 8 degrees (0.2g); Let the maximum horizontal seismic influence coefficient αmax = 0.45; and let the characteristic period = 0.35s.
3. Build isolated structure: creating an isolation layer at the bottom of the non-isolated version of the twin-tower shear-wall structures with an enlarged basement.
4. Apply response spectrum method & Time-history analysis method: The response spectrum method, like that used for non-isolated structures, was employed for isolated structures. The time-history analysis used seven seismic waves, including five natural waves and two artificial ones. Additionally, the peak earthquake acceleration is set at 200cm/s^2.