489米超高层建筑抗倒塌分析案例研究

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

超高层建筑的抗倒塌设计是其安全设计中的重要一环,保障超高层建筑的抗倒塌性能对于保护人民生命财产安全具有重要意义。现阶段系统考虑超高层建筑抗地震倒塌和抗连续倒塌研究的工程案例还比较有限。该文对一489 m超高层结构的抗地震倒塌能力、抗爆能力和关键竖向构件拆除后的抗连续倒塌能力进行了分析,结果表明:该超高层结构在所选取的8组地震动记录下的抗倒塌安全储备系数为3.59,抗地震倒塌性能良好;在爆炸距离为5 m的情况下箱包炸弹的TNT当量达到约3.2 t时可以造成结构倒塌,在爆炸距离为10 m的情况下,面包车炸弹的TNT当量达到约10.0 t时可以造成结构倒塌;在巨柱、塔冠钢柱、次级钢框架吊柱和承重柱等关键竖向构件中的一根构件被拆除后,结构备用传递路径能够发挥作用,整体结构抗连续倒塌性能良好;在拆除两根底部巨柱的情况下结构未发生倒塌,而在拆除三根底部巨柱的情况下,若拆除的巨柱不是建筑相邻角四根巨柱的三根,则结构依然可以不发生倒塌,反之则发生倒塌。该文分析方法和结果可以为类似超高层建筑的防倒塌设计提供参考和借鉴。

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.