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Saferoads have developed an innovative traffic delineation and worksite protection solution that is able to provide a continuous temporary traffic barrier deployment at a tight radius. The Saferoads T-Lok Steel Wedge incorporates a steel wedge piece which can be used in-between individual T-Lok freestanding temporary concrete barriers to facilitate placement at tighter radii. This innovation provides a vast improvement in safety due to the continuous barrier placement without the need for crash cushions, and improved efficiency with staged intersection deployment.
The steel wedge has ASBAP approval to 60km/h. It enables the 3.66m barrier to be deployed on a radius as tight as 8m and the 5.49m barrier on a radius as tight as 12m. This is compared to a 30m radius without the steel wedge, a significant advantage for worksite safety on intersections and roundabouts.
The Saferoads T-Lok Barrier consists of a series of individual concrete barrier sections. The barrier ends comprise “T” and “C” connections that interlock during deployment. The wedge fits and connects between the joins with ease.
Saferoads steel wedge enables the standard T-Lok Barriers to be deployed at a tighter radius by adding a wedge piece in between the T and C connectors. The wedges are fully welded and are as strong as the T-Lok C and T connectors to ensure the barrier connections are not compromised when the steel wedges are used. The steel wedges are a substantial unit, weighing approximately 60kg.
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Angles from 6 up to 32 degrees are achievable with the steel wedge. It can be used either way up to enable the barriers to curve left or right regardless of the C and T orientation. This design is all that is needed for left or right curves, starting with either a C or T connector. The steel wedges should only be used where traffic speeds are restricted to 60km/h or below. The deflection where wedges are used should be conservatively set at 5m, and the distance to excavation should be 4m.
The 3.6m T-Lok Barriers can achieve a 30m radius, with a standard maximum 7 degrees angle at each joint. The steel wedges allows each joint to be deployed at an angle from 6 degrees (Figure 1) up to 32 degrees (Figure 2), enabling a deployment radius as tight as 8m when steel wedges are used in-between each T-Lok barrier.
Figure 1: Plan view of two barriers laid out with the wedge at 6 degrees
Figure 2: Plan view of two barriers laid out with the wedge at 32 degrees
Saferoads have undertaken LS-Dyna Simulations (SIMs) to evaluate the performance of the steel wedge under different scenarios. The SIMs evaluate the structural strength of the steel wedge, and how it interacts with the standard T-Lok Barriers. These simulations also show the behaviour and likely outcome of impact scenarios, yet to be tested by any safety barrier manufacturer.
The SIMs setup includes barrier models, concrete and steel characteristics, and other variables such as friction, have been taken from a validated model of the real-life MASH TL-3 crash test. This validation was completed with the assistance of University of Melbourne research team.
The simulation shown in these videos was performed on an 8m radius deployment with steel wedges, and a vehicle impacting at 60km/h. During the simulation, the layout of the barrier and wedge setup allowed the impact forces to be directed longitudinally along the barriers. This resulted in compression loading on the barriers instead of a bending load. This in turn allowed the wedge and barriers to remain intact, the vehicle was bought to a controlled stop and did not penetrate through the barriers. The use of the Steel Wedge with the T-Lok Barriers not only improves the ability to place barriers at a tighter radius, but it also reduces the severity of impact on the occupant of a vehicle when impacting the continuous barrier system.
“No other barrier to my knowledge, steel, concrete or plastic would bring the vehicle to a controlled stop in less distance than our T-Lok with the steel wedges.”
For further guidance and assistance on the advantages and proper use of the T-Lok Steel Wedge, contact the Saferoads team of road safety specialists on 1800 060 672.
