Robustness analysis of vertical resistance to progressive collapse of diagrid structures in tall buildings

Abstract

SummaryIn order to investigate the vertical resistance to progressive collapse and the evolution of its robustness in the process of loading, a quantitative method of the robustness index of diagrid structure is established based on the mechanical properties of the components and the vertical bearing capacity of the structure. A scale experiment model of diagrid tube structure is established in laboratory which verified the availability of the proposed robustness quantification method. Results demonstrated that, the axial force of inclined column is pressure, and the axial force of ring beam is tension under vertical load. The ring beam is the main restraint to the side bulge of the diagrid structure. The welded strength of the inclined column have great influence on the vertical bearing capacity, so it is necessary to consider the reduction of the strength of welded joint. The influence of the welding line of the joint can lead to the plastic stage of the local components of the structure, which makes the structural robustness worse. In addition, the experimental study and numerical simulation results verify that the proposed method of robustness coefficient quantification for diagrid tube structure can accurately and reasonably evaluate the resistance of vertical progressive collapse performance.