Today’s guest author is Ken Haley. Ken is our resident expert on all things workzone safety and impact attenuation. In today’s post, we asked Ken to answer the most frequently asked questions he and our sales team receive about the MASH Eligible HV2 TL-4 steel barrier.
1. How is the HV2 fixed to the roadway?
The HV2 is a hybrid steel barrier that contains internal concrete ballast. The combination of the ballast weight and the proprietary connectors that link the system together, give the HV2 superior performance without the need for roadway anchoring. The system achieves low deflection and maximum vehicle containment while eliminating roadway or bridge deck damage due to traditional anchoring systems.
The HV2 concrete ballast is a one-time installation, the steel barrier segments receive approximately .95 cubic yards of agile flow concrete mix which is pumped into the barrier segments. The ballast installation is a one-time application, after which the HV2 can be deployed and is a maintenance free system.
2. What level of testing has the HV2 undergone
The HV2 system has been tested and eligible for both MASH TL-3 and TL-4 test procedures.
3. What is the level of deflection?
As required by MASH the system was tested at 100km/h (62mph) at a 25° impact angle. All other deflection data presented was interpolated realizing LS-DYNA simulation. The combination of ballast weight and the proprietary connectors allows the HV2 to achieve impressive vehicle containment and low deflection in both TL-3 and TL-4 conditions.
| TL-3 5,000 LBS (2,270 KG) Vehicle | |||||
|---|---|---|---|---|---|
| SPEED | 25° | 20° | 15° | 10° | 5° |
| 62 MPH / 100 KM/H | 4′ 10″ (1.47m) | 3′ 11″ (1.18m) | 2′ 11″ (0.88m) | 2′ (0.59m) | 1′ (0.30m) |
| 56 MPH / 90 KM/H | 4′ 5″ (1.33m) | 3′ 7″ (1.07m) | 2′ 8″ (0.80m) | 1′ 10″ (0.54m) | 11″ (0.27m) |
| 50 MPH / 80 KM/H | 3′ 11″ (1.18m) | 3′ 2″ (0.95m) | 2′ 4″ (0.71m) | 1′ 7″ (0.48m) | 10″ (0.24m) |
| 43 MPH / 70 KM/H | 3′ 5″ (1.03m) | 2′ 9″ (0.83m) | 2′ 1″ (0.62m) | 1′ 5″ (0.42m) | 9″ (0.21m) |
| 37 MPH / 60 KM/H | 2′ 11″ (0.89m) | 2′ 4″ (0.71m) | 1′ 9″ (0.53m) | 1′ 3″ (0.36m) | 8″ (0.18m) |
| 31 MPH / 50 KM/H | 2′ 6″ (0.74m) | 2″ (0.59m) | 1′ 6″ (0.44m) | 1′ (0.30m) | 6″ (0.15m) |
| 25 MPH / 40 KM/H | 2′ (0.59m) | 1′ 7″ (0.48m) | 1′ 3″ (0.36m) | 10″ (0.24m) | 5″ (0.12m) |
4. How is the end treated?
The TrafFix SLED water-filled crash cushion is a tested and approved temporary attenuator system for use with the HV2 in Workzone applications utilizing the standard SLED Universal Transition. HV2 Safety Barrier installations require appropriate end treatments to ensure occupant safety in the event of an impact to the end of the system. HV2 Safety Barrier can be used with any approved end treatment, including SLED Crash Cushion with Transition Kit, or tapering the barriers outside the Clear Zone with no end terminal attached.
The SLED Water Filled Crash Cushion with Transition Kit has been successfully tested with the HV2 Safety Barrier. This configuration does not require any anchoring to the ground and is completely freestanding. Refer to page 12 for deployment details.
