How cable barriers work
Cable barriers consist of a number, typically three or four, of high tension steel ropes whoch are anchored to the ground at each end and kept in position by posts at about a few metres spacing. There is no limit to the distance inbetween end anchors but in practice, it is often benefitial to separate installations with anchors at about every three to five km if the total distance is even longer.
Cable barriers possesses unique features as it catches vehicles and allow it "hang" in the cables similar to a hammock whilst the posts bend as they are hit and the cables are released from the posts. This causes low levels of accelerations and crash violence to the occupants of the vehicle. The vehicle will typically not be thrown back out to the carriadgeway as is often the case in collisions with other road barrier technologies.
Similarly to everything else in the world, cable barrier manufacturers have different approaches and develop their products in different directions. Needless to say, of course we believe SAFENCE to be the best product available. SAFENCE wire rope safety fence is developed in a way that allows the systems to remain its functionality even after a typical collision, under normal circumstances cables remain (more or less) their correct heights even with a number of posts missing. In addition to standarised collsion tests, we have also carried out crash tests simulating previously damaged installation, at extra high speeds as well a in extra sharp collision angles.
Steel properties cause the cables to extend as surrounding temperature rises and shorten as temperature drops. This means that cable tension varies depending on current air temperature, the barrier will stiffen up when it is cold outside and become softer on hotter days.