In order to obtain basic knowledge for establishing a rational impact-resistant design procedure of the steel posts for rockfall-protection fences embedded into the protection walls, 3D elasto-plastic impact response analyses were conducted taking impact velocity of the weight as variables. The applicability of the proposed method was verified by comparing with the experimental results in the case of using the through-type steel posts and the amount of the numerically simulated absorbed energy of each member was also discussed. The results obtained from this study were as follows: 1) impact resistant behavior of the steel posts except for rotation of protection wall can be appropriately simulated, and 2) it was confirmed numerically that more than 80% of the input energy was absorbed by the deformation of the steel post.
