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.
Median barriers are installed in order to protect from oncoming traffic. A median barrier is designed to be hit from both directions. These systems may be installed in narrow medians as well as in wide medians, in centre line or offset towards either direction.
Median barriers are typcally installed in carriageway or support strip depending on road design. Most of our systems are available as three and four cable systems, designed and approved in accordance with European EN 1317 as well as American NCHRP 350 and MASH.
Side barriers are tyically installed in the support strip on the side of the road. In general, SAFENCE side barriers and median barriers are the same products but installed in different locations. Most of our systems are available as three and four cable systems, designed and approved in accordance with European EN 1317 as well as American NCHRP 350 and MASH.
Slope barriers are installed behind slope break point. SAFENCE slope barriers are designed to take care of vehicles flying out over the slope as well as low enough to take care of vehicles following the slope gradient.
Most of our systems are available as three and four cable systems, designed and approved in accordance with European EN 1317 (including Swedish slope barrier amendment TRVMB 350 as well as American NCHRP 350 and MASH
A few advantages from installing barriers behind slope break point are:
More space for pedestrians and bicycles.
More space for snow and great snow remowal advantages with less melt water on the road.
Less frequent collisions dure to the greater distance from traffic.
Increased space for vehicles that break down.
No widening of the hard shoulder is required.
Less of a "wall" effect.
Aesthetically more attractive design.