Guardrail installation in accordance with the requirements of SANS 1350:2005 is done specifically to improve road safety for motorists, pedestrians and cyclists. W-beam guardrails act as restraint systems. With the very rationale of these systems being to reduce the number of fatalities on South African roads, choosing the correct materials, components, and installation locations is imperative. To this end, the SANS 1350 is the benchmark standard. Road agencies such as SANRAL, government departments such as the Department of Transportation, road engineers, and municipal urban planners are key decision makers in the selection and correct installation of guardrail systems to improve road safety in South Africa.
Main Purposes of Guardrails
Installation is done to reduce the number of fatal accidents on the South African roads. This is made possible because the barriers are installed at the following locations:
- At the edge of a sharp bend in the road;
- At the edge of a mountain pass to prevent straying vehicles from going over the side of a cliff;
- At the side of a bridge to prevent erring vehicles from going over the side onto traffic below or into a water source;
- On the side of an urban road to protect pedestrians and cyclists on the pavement from being run over by vehicles straying from the road, and to prevent motorists from driving onto the pavement on purpose;
- Next to the road to protect erring vehicles from colliding with unforgiving obstacles such as walls, street signs, rock faces or trees;
- In the median of highways to prevent vehicles from making U-turns into the fast lanes of the opposite direction highway and to prevent accidents from one highway from spilling over to the next.
Guardrail installation at the edge of a road helps to improve road user confidence, especially at night when it is difficult to see the edge. This helps to reduce the risk of median clustering, often associated with head-on collisions. Knowing where the end of the tarred area is makes it possible for road users to keep to the left and thereby create a wider gap between opposite flowing lanes.
Given the important functions of the road safety barriers, it is imperative that these systems are made for maximum safety. Although the presence of a barrier cannot be a guarantee of the complete prevention of accidents, severe injuries or even death, correct Guardrail Installation and placement can help to reduce the number of serious incidents. The barriers serve to:
- Redirect an erring vehicle to the original path;
- Reduce the speed of travel when a vehicle hits it from a side angle as the friction caused by the side impact reduces speed, providing the driver with the opportunity to bring the vehicle to a controlled stop or to correct the mistake without serious incident;
- Prevent a straying vehicle from breaking through the barrier and into a hazardous obstacle or situation;
- Prevent a vehicle from going over the barrier into an obstacle.
Components of a W-beam Guardrail System
Installation of the W-beam barrier includes the posts that secure the system to the ground, the bolts that are used for fixing the steel beams to the posts, the galvanised W-beam steel beams, delineators on the beams, and end-terminals.
Many factors are taken into consideration to determine whether or not a road safety barrier installation is better than not having any type of barrier at all. These include, but are not limited to:
- Space available behind the barrier to allow for some movement of the barrier steel in the event of a severe impact by a speeding vehicle;
- Space available behind the barrier to prevent impact with the obstacle against which it must protect the road users;
- Type of soil where the posts must be installed;
- Ground surface space available for installation of the posts;
- Type of obstacle or hazard against which it must protect.
Since any type of road safety barrier also poses a level of risk for the road users, it is imperative to consider whether collision with the barrier has a higher level of fatality or injury severity risk than collision with the obstacle or the level of hazard against which it is intended to protect. If enough clearance space is available for the safe correction or the driving mistake or to bring the vehicle to a controlled and safe stop, then the choice is normally to go without a barrier. In this instance, the average speed of travel on the path must be considered. In short, guardrail installation is only done where it is essential for improvement in road safety.
One also has to consider whether another type of restraint system or barrier will not be better suited to the particular space. If it is determined that the W-beam guardrail is best for the situation, then the correct Guardrail Installation procedure must be followed. To this end, installation must be done according to set standards, using products manufactured according to widely recognised standards such as SANS 1350.
Characteristics of W-beam Guardrails
The W-beam panels are attached to posts which are fixed to the ground. The entire system works together to prevent breakthrough while also acting to redirect and to absorb kinetic impact energy across the entire length of the installed barrier.
The galvanised beams last many years as the galvanisation protects the steel against corrosion. This helps to reduce the maintenance required while also reducing the cost of usage over the entire period. The beams are fitted with delineators to make them visible in low-light and night driving conditions. The ends are either buried or fitted with end-terminals to prevent penetration of a vehicle body upon head-on collision with the end of the beam system.
Where to Source and Purchase Guardrails?
The Armco Superlite W-beam guardrail systems have gained international acceptance over the years. Installation guidelines are provided for the durable systems. Sections are available in 4 m and 3,81 m lengths, and special lengths are available upon request. Beam sections can be curved according to the curve radius requirements for the particular stretch of road. Curving can be done for any radius from 3 m to 45 m.
The company provides bull-nose and standard end-terminals. Clients can request hot-dip beams (galvanised according to SANS 121/ISO 1461, although uncoated beams are also available. The beams are attached to timber posts with bevelled or domed tops.
The manufacturing process includes several quality control measures. Customers have the option of steel posts instead of the standard timber posts. The steel posts are made according to the customer needs. The delineators are available in “V” and “D” shapes. Keep in mind that the Department of Transport requires the “D” shaped ones. The delineators are made from chromadek material, ensuring longevity.
View the guardrails available and get in touch with Armco Superlite for pricing and Guardrail Installation information.