Safety fencing serves the crucial purpose of containing vehicles within their travel lanes, preventing them from rebounding into traffic and causing further hazards. Traditional fencing designs prioritize energy absorption upon impact, minimizing forces exerted on the vehicle and guiding it back onto the correct path.
Concrete profile barriers, however, take a different approach. Their primary function is not to absorb energy but to redirect the errant vehicle. They achieve this through a curved profile that allows the vehicle to mount and partially ascend the barrier without overturning. This concept, as explained by Arthur Wignall, Peter S. Kendrick, and Roy Ancil, relies on the interaction between the vehicle and the barrier’s shape.
The specific interaction varies depending on the angle of impact. In shallow-angle crashes, the car climbs the lower slope of the barrier. At steeper angles, the bumper engages the upper slope, causing the car to ride upward while the wheels ascend the lower slope. This controlled lifting prevents excessive elevation, which could lead to rolling.
The design of the barrier’s sloping faces is critical. A smooth finish is preferred to minimize friction between the wheels and the barrier, as excessive friction could contribute to unwanted lifting forces. The goal is to transform the car’s kinetic energy into potential energy as it climbs the barrier, which is then converted back into kinetic energy as the vehicle returns to the roadway.
In conclusion, concrete profile barriers prioritize redirection over energy absorption. Their curved profiles, combined with the specific interaction between the vehicle and the barrier’s surfaces, effectively guide errant vehicles back onto their intended path, enhancing road safety.