As a basic study phase of the applicability of standard box culverts to shelter facilities, numerical simulations were conducted to evaluate the impact resistance of a 240 mm thick box culvert sidewall against projectiles ranging from 0.0079 kg to 45.3 kg in mass and 228.6 m/s to 655.4 m/s in impact velocity. The penetration depth and spall protection threshold thickness of the wall, determined experimentally, were compared with simulation results, showing good agreement. Based on the observed damage patterns, the impact resistance of the box culvert sidewall was improved by reinforcing it with a 10 mm steel plate. The reinforced structure demonstrated sufficient impact resistance against a 16 kg projectile at 228.6 m/s.
