Dynamic response and damage behavior of corrugated steel-concrete-corrugated steel sandwich arches against rockfall impact

The corrugated steel-concrete-corrugated steel (CSCCS) sandwich arch, as a novel protective structure, shows significant potential in resisting rockfall impact. However, current research on its impact performance remains insufficient. Therefore, this study investigated the coupled effects of key design parameters through a series of numerical simulations, aiming to elucidate the dynamic response and damage behavior of CSCCS arches under rockfall impact. The results indicate that the failure mode of the CSCCS arch consists of both local indentation and global bending deformation. As the rockfall diameter increases, the failure mode transitions from localized shear failure to global bending failure. Energy dissipation is dominated by the concrete core (69.3%), followed by the top (15.2%) and bottom (8.7%) CS plates. Although shear connectors contribute the least (6.8%), they are critical for maintaining composite action. Structural resistance can be enhanced by increasing the thickness of either the CS or concrete. However, optimal performance requires a balanced stiffness-ductility match to prevent excessive global deformation or brittle shear failure. Crucially, the concrete penetration rate was proposed as a quantitative metric to characterize the failure mode, providing a reliable basis for performance evaluation.