Dynamic Behavior of Progressive Collapse of Long-Span Single-Layer Spatial Grid Structures

Abstract

Long-span, single-layer spatial grid structures are widely used in public buildings. The progressive collapse of such structures could cause great losses of property and human life. To accurately capture the performance of a structure in progressive collapse, an efficient dynamic behavior analysis should be conducted. In this paper, a multi-degree-of-freedom simplified model was established to represent the progressive-collapse dynamic behavior of single-layer spatial grid structures. Based on the simplified model, two dynamic behavior modes were identified: ordinary and specific dynamic behaviors. In ordinary dynamic behavior, the dynamic effect caused by local failure cannot be transmitted, and the displacement responses of the joints in the failure area are symmetrically distributed based on the final equilibrium states, with the gradual attenuation of the dynamic effect. For the specific dynamic behavior, the dynamic effect is transmitted and a disorganized response of single-layer spatial grid structures occurs. Furthermore, the dynamic progressive-collapse behaviors of six full-scale typical domes were analyzed with a verified numerical simulation. The results indicate that a multi-degree-of-freedom system is necessary for accurately reflecting the dynamic behavior of single-layer spatial grid structures. The middle position between vertex and supports can be defined as the important area of reticulated domes, where a member’s failure would have a significant effect on structural performance. If a specific dynamic behavior plays a dominant role in the overall structure, the progressive-collapse resistance may be improved for a single-layer spatial grid structure.