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ABOUT

CONCRETE & STEEL BARRIERS

Todays high speed (80-110kph, 50-70mph) road construction sites use a variety of safety barriers to improve the safety for construction workers and motorists travelling through these traffic disruptions. Safety barriers should be used where the risk to drivers, road workers, pedestrians or cyclists is higher than if there is no barrier.

The two most common types of safety barriers used on high speed construction sites are Portable Concrete Barriers (PCB’s) and 12-15m long Temporary Steel Barriers. Portable Concrete Barriers have been in use for several decades, the original designs have not changed significantly over that time.

Portable Concrete Barriers (PCB) have performed adequately across the years as safety barriers, however, they have limitations in their use. Many PCB’s remain public domain designs that have not been crash tested to the latest crash testing standards. Some barriers have passed tests with larger vehicles but are too stiff to work with smaller vehicles and have been “deemed to comply” so that industry has a solution.

about concrete barriers
CONCRETE BARRIERS ARE NOT

PROPERLY TESTED

It is not unusual to see temporary concrete barriers pinned to the ground and deemed to be safe to work behind. This method of pinning of concrete has never been tested using globally accepted test standards. It is therefore not known with any certainty how far the barrier will deflect when hit, and what danger that poses to workers. Equally alarming is that there is no test data to prove the effect on a vehicle and driver if the temporary concrete barrier is impacted while pinned to the road. Some jurisdictions deem the deflection to be 2 4” however there is no publicly available test evidence to support this.

Barriers are designed to reduce the chance of injury or death. An untested temporary concrete barrier, in an untested deployment arrangement cannot satisfy this requirement.

HEAVY LOAD WITH A

SHORT LIFECYCLE

Portable Concrete Barriers are very heavy at 470lbs/foot (700 kg/meter) and require significantly more truckloads for every deployment compared to other safety barriers. Construction sites are notoriously rough on equipment, and Portable Concrete Barriers, by virtue of their construction, are a brittle product that breaks easily creating a barrier that has a 3-5 year life cycle as a serviceable safety barrier. Once the barrier is no longer useable as a safety barrier it is difficult to recycle.

In crash testing performance, to achieve a deflection, less than 1 meter, Portable Concrete Barriers are required to be anchored to the road surface. Some designs require this anchoring every 1.2m (4’). The addition of anchor clips onto the side profile of Portable Concrete Barriers creates another wear point for the concrete to break off, further reducing the practical life of the barrier.

heavy load with a short lifecycle

HIGH SPEED
CONSTRUCTION SITES

ABOUT THE

DEFENDER 100™

Defender 100™ is the next evolution in temporary steel barriers. Experience at roadworks, and at contractors depots has shown the team at Safe Barriers that while properly tested temporary steel barriers offer the best solution for safety on work sites when compared to concrete, and in some cases plastic water filled there are issues when it comes to handling, storage, transport and deployment of a 12-15m (40-50ft) temporary steel barrier.

The Defender 100™ is only 3.9 m long and weighs only 303 kg. With feet at 1.35 m (4’5’) when a barrier is lifted using a forklift there is a very small overhang, improving safety. On the road side, the same level of safety is achieved because it easy for one person with a lanyard to control a much lighter 3.9m temporary steel barrier compared the more cumbersome 1000kg 12-15m (40-50 ft) temporary steel barriers.

Defender Barriers has taken everything that is good about temporary steel barriers and improved them. Lighter than portable concrete barriers, the safety advantages temporary steel barriers and a dramatic improvement in depot and site handling safety to help prevent serious injury or death to workers and drivers.

ADVANTAGES OF

PORTABLE TEMPORARY STEEL BARRIERS

Over the past decade Temporary Steel Barriers have been introduced to address some of the issues with Portable Concrete Barriers. These barriers are significantly lighter than Portable Concrete Barriers, by a factor of approximately 7-8, this means that Temporary Steel Barriers reduce the transport required by at least 4 times for the same lineal length of temporary barrier.

These Temporary Steel Barriers have been designed with very long individual lengths 12-15m (40-50ft). To deliver a 1000 metre (2/3 mile) barrier run in temporary steel barriers will require on average only 8 vehicle movements. The reduced vehicle movements mitigate the risk of incident or injury caused by vehicles moving through the work site. Importantly for the contractor, site costs are also reduced.

importance of an optimised length of a barrier
IMPORTANCE OF AN OPTIMISED

LENGTH OF A BARRIER

The length of the barrier can be problematic on difficult sites, with no ability to adjust barrier direction except every 12-15m (40-50ft). With a standard deployed radius of 200-250m it is often the case that the contractor is required to hold a variety of mitered sections at different degrees of arc and both left and right turn. Road sag can be an issue because of the length of these temporary steel barriers, where too steep a sag makes the barriers useless.

This means that on any one work site, it could be necessary for a contractor to hold 12-15m (40-50ft) temporary steel barriers and 2-6m concrete barriers and perhaps even plastic water filled to accommodate some of the more difficult locations. Which is a costly time consuming exercise in storage, handling, logistics and deployment. It requires multiple work methods, multiple safety procedures and multiple assets for deployment. When you add this to the overall length of the barriers, 12-15m (40-50ft), safety issues at storage depot’s can arise.

BETTER SOLUTIONS WITH

THE DEFENDER 100™

There are two common methods for handling temporary steel barriers at a depot and at roadside. Firstly, is the use of double slings from lifting points on the top of the barrier. This will require a crane operator and a spotter who will guide the barrier in to place. This means a 1000kg 12-15m (40-50 ft) piece of steel is airborne on a work site, next to a road, usually with just one person guiding it with a lanyard. The barrier is cumbersome and does not lend itself easily to manoeuvring.

The second most common method is the use of a forklift through the feet. Because of the weight of a steel barrier a 2.5 t to 5 t forklift is often used for handling. While the weight of the barrier is well within the limit of the forklift, at 12-15m (40-50 ft) a large part of the barrier is hanging unsupported on either side of the forklift creating a dangerous tipping hazard. This danger is particularly high at road side storage yard which usually only compacted soil and is often uneven.

Having seen many sites where barriers where swaying during deployment and handling it was decided that the Defender Barrier Temporary steel barriers would be designed to improve safety in handling.

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road deployments based on actual test information
ROAD DEPLOYMENTS BASED ON

ACTUAL TEST INFORMATION

One of the great advantages of the move to 12-15 metres (40-50 ft) temporary steel barriers is that roadside deployments are designed based upon actual test information. All of the temporary steel barriers have been approved for use based upon actual crash test data. It is interesting to note that temporary steel barriers are often tested to determine a low deflection option. The traffic designer for a particular work site can take this data in to account when writing safe work practices.

The take up of temporary steel barriers globally, indicates that contractors, road authorities and designers need clarity on performance to minimize risk on a work site.

Because they are not concrete, it can be argued that workers become more cautious about standing immediately behind a barrier, as they are prone to do with PCB’s. Empirical evidence suggests that a site worker will stand back from the temporary steel barrier as their own site safe work practice dictates, because they do not have the false sense of security that comes with portable concrete barriers.

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