Seismic Performance Evaluation of Steel Diagrid Buildings

Abstract

In this study the seismic performances of axi-symmetric steel building structures with circular plan shape were evaluated based on the ATC-63 approach. For analysis models, thirty-three-story vertically convex, concave, and gourd-type axi-symmetric buildings were designed using diagrid structure system, and their seismic performances were compared with those of the cylinder type regular steel structure. Seismic fragility analyses were carried out using twenty-two pairs of earthquake records to obtain the probability of failure for a given earthquake intensity. The validity of the response modification factor used in the seismic design of the model structures was also investigated. Based on the analysis results it was concluded that the response modification factor of 3.0 used in the design of the model structures is acceptable for the ATC-63 methodology. It was also observed that the seismic safety margin for a specific level of earthquake decreases as the vertical irregularity of the structure increases.