Dynamic response analysis of hollow thin-walled pier rigid-frame bridge under rockfall impacts

Abstract

Rockfall hazards pose a severe threat to the safety of mountain bridges. As one of the predominant bridge types in such regions, hollow thin-walled rigid-frame bridges still lack sufficient research on their impact resistance mechanisms against rockfalls. To address this, this study establishes a refined finite element model using LS-DYNA to systematically investigate the dynamic response and damage mechanisms of these bridges under rockfall impact. Numerical analyses reveal that: (1) For a given impact energy, increasing the rockfall diameter significantly amplifies pier displacements, with shear damage becoming more severe when the impact location is closer to the pier base; (2) Higher reinforcement ratios can localize damage to the front wall, reducing side panel shear failure risks; (3) Decreasing stirrup spacing effectively reduces concrete damage zones; (4) A power-law relationship model (R2 = 0.94) between peak impact force and impact energy is proposed based on numerical results. The findings provide theoretical support for the impact-resistant design of mountain bridges.

Keywords

Bridge engineering / Dynamic response / FEM / Hollow thin-walled rigid-frame bridge / Damage analysis

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Funding

Sichuan Province Science and Technology Support Program(2024NSFSC0932)

National Natural Science Foundation of China(52008047)

RIGHTS & PERMISSIONS

The Author(s)