Study on the Distribution of Survival Space in Grid Structures Subjected to Overload Collapse

Taking an actual engineering space truss structure as the research object, nonlinear dynamic collapse simulations were conducted on the ANSYS/LS-DYNA platform. By applying three loading conditions—full-span, half-span, and one-third-span—the collapse behavior characteristics of the space truss under overloads in different areas and the distribution patterns of its internal survival space after collapse were compared and analyzed. The results indicate that an inverse relationship is observed between the loading area and the distribution size of the survival space, with the survival space primarily concentrated in the region opposite the loading zone. The initial failure locations of the truss structure are mostly found at the edges of the loading area, particularly at the corner joints. Both the loading area and the initial failure locations jointly govern the propagation direction of the collapse and determine the morphological characteristics and distribution patterns of the survival space. Based on these findings, the distribution morphological features of the survival space under different working conditions are further summarized, and corresponding rescue strategies are proposed. This study can provide a theoretical basis for the anti-collapse optimization design of space truss structures and post-disaster emergency rescue, contributing to the enhancement of the safety level of long-span space truss structures and the protection capability of urban public safety.