Influence of degradation at the base of a support post in a collapse of an old guardrail: A forensic analysis

After a violent crash that took place at the entrance of the road on a bridge, the guardrail installed as protection collapsed and the vehicle left the roadway. As at the base of a number of guardrail posts, a situation of severe corrosion was found evident, its influence on the resistance and on the mode of collapse of the guardrail was explored. To this purpose, the information about the state of the place collected immediately after the accident and the plastic deformations observed on the deformed guardrail contributed decisively to reconstructing the dynamics of the impact. Later, using the same assumptions and the same methods of calculation used to assess the strength of the guardrail in a condition of degradation, the impact of a similar guardrail in perfect structural conditions was simulated. The comparison between the two analyses indicated the limited influence of corrosion on the guardrail in question and on the dynamics of the accident that had occurred.