The Effect of Using Skybridge and Its Various Design Methods on the Performance of Multitower

ABSTRACT

The purpose of this research is to evaluate the effect of using a truss‐type skybridge and different design methods on the performance of tall structures. Three design methods were examined, including force‐based design, energy‐based performance design, and a supplementary configuration using isolators and dampers, which was also examined to illustrate an upper‐bound elastic scenario for comparison purposes. The study first analyzed twin 50‐story towers, followed by a 50‐story and a 40‐story tower with a core‐braced and outrigger truss system. After initial design, the structures were nonlinearly modeled in PERFORM‐3D software and subjected to 28 near‐field ground motion records recommended by FEMA P695, and the average responses were finally compared. The results illustrated that the force‐based design method could not provide appropriate performance for the skybridge under seismic loads. The energy‐based performance method ensured the skybridge met the Life Safety performance level, while the force‐based method with isolators and dampers guaranteed elastic behavior of the skybridge. The findings also indicated that both the use of a sky bridge and its design methods significantly affect structural performance. In the twin towers, the average roof displacement decreased by 9.2% when the skybridge was designed using the energy‐based performance design method and 7% when designed using the force‐based method with isolators and dampers.