Road and Bridge Barriers

The New Jersey Concrete Safety Shape Barrier (NJ-shape or also called Jersey type barriers) is the most well known barrier type. The Jersey barrier wall was originally developed to divide multiple lanes on a highway and intended to minimize damage and reduce the likelihood of a car crossing into oncoming lanes in the event of a collision.

For the more common shallow-angle hits, the Jersey barrier is intended to minimize sheet metal damage by allowing the vehicle’s tires to ride up on the lower sloped face. For higher impact angles, the Jersey barrier is actually a multistage barrier. The front bumper impacts the upper sloped face and then slides upwards. This interaction initiates the lifting of the vehicle. If the bumper is relatively weak, the front end starts to crush before any uplift can occur.

Then, as the vehicle becomes more nearly parallel with the barrier, the wheel contacts the lower sloped face. Most of the additional lift of the vehicle is caused by the lower sloped face compressing the front suspension. However, wheel side-scrubbing forces provide some additional lift, particularly if the barrier face is rough.

Therefore, exposed aggregate and other rough surface finishes should be avoided. Modern vehicles have relatively short distances between the bumper and the wheel; as a result, bumper contact is followed almost immediately by wheel contact. It is only necessary to lift the vehicle enough to reduce the friction between the tires and the paved surface. This aids in banking and redirecting the vehicle. If the vehicle is lifted too high into the air, it may pitch, or roll, which can cause the vehicle to roll over when the wheels come in contact with the ground again.

Preferably, concrete safety shape barriers should be adjacent to a paved surface so that the wheels cannot dig into the soil and cause the vehicle to overturn.
Modern variations include the F-Shape Barrier. The F-Shape is similar to the Jersey Barrier in appearance, but has different angles and can be much taller. The F-Shape is thought to be the best current concrete barrier design. It takes its name from a set of tested barriers that were assigned letters as identification such as Type B1, B2, C, E and F.

Use the links below to download the Barrier Cross Section Diagrams: