To investigate the effect of cross-sectional reductions in the members due to aging on the protective performance of a rockfall protection fence, impact loading tests were conducted on the fence with both flanges reduced in thickness near the base of the intermediate posts. The findings of this study were as follows: 1) when both flanges near the post base were reduced in thickness by 2 mm, the local deformation and yielding of the posts tended to be concentrated in the reduced thickness area; and 2) it was confirmed that when a steel weight with an energy of about 45 kJ was applied to the deteriorating fence, the cracks occurred near the U-bolt holes of the flange located at the post base. However, no indications of failure or unexpected damage were observed in the remaining members, and the fence was able to capture the weight.
