CASE STUDY ON COLLAPSE RESISTANCE OF A 489-METER SUPERTALL BUILDING

In the safety design of supertall buildings, the collapse resistance analysis account for one significantly important part, and ensuing sufficient collapse resistance of supertall buildings is of great significance to protect the safety of people's lives and property. To the authors’ knowledge, the design cases that comprehensively consider earthquake-induced and progressive collapse resistances are still relatively limited. In this study, analyzed are the collapse resistances of a 400-meter supertall building under earthquakes, blasts, and the conditions that critical vertical components are removed. The analysis results reveal that: the collapse margin ratio of the supertall structure under the selected eight ground motion records is 3.59, indicating a satisfactory collapse resistance under earthquakes; a luggage bomb with a TNT equivalent of approximately 3.2 tons can cause structural collapse at a distance of 5 m, while a van bomb with a TNT equivalent of approximately 10.0 tons can cause structural collapse at a distance of 10 m; after removing one critical vertical component, such as one mega column, one tower crown steel column, one secondary steel frame suspender, or one load-bearing column, the remaining structural alternative load paths can still function, demonstrating a good overall progressive collapse resistance; the structure does not collapse when two bottom-story mega columns are removed; however, if three bottom-story mega columns are removed, the structure remains intact if the removed columns are not among the adjacent corner columns; otherwise, collapse occurs. The analysis method proposed and the results studied can provide a reference for the collapse design of similar supertall buildings.