RAMSHIELD® High Containment

RAMSHIELD® High Containment achieves controlled redirection of errant vehicles by releasing the thrie-beam guardrail from the post at an optimal load to retain rail height, limit dynamic deflection and to allow the post to collapse without tripping the vehicle.

The separation of the thrie-beam guardrail from the post is achieved by a release tab incorporated into the post. The tab is designed to pull forward and tear from the post and remains connected to the thrie-beam rail to ensure there is no debris from the system that may otherwise present as a danger to other motorists.

RAMSHIELD® High Containment has been crash tested in accordance with MASH Test Level 4 and Test Level 3 as follows:

• 10,000kg rigid truck travelling at 90km/h and 15 degrees. Impact energy of 209kJ.
• 2,270kg pick-up truck travelling at 100km/h and 25 degrees. Impact energy of 156kJ.
• 1,100kg passenger car travelling at 100km/h and 25 degrees. Impact energy of 76kJ.

The Manual for Assessing Safety Hardware (MASH) is an update to and supersedes NCHRP Report 350 for the purposes of evaluating new safety hardware devices. MASH is also the basis of testing procedures for road safety systems as stated in AS/NZS 3845.1: 2015 Road Safety Barrier Systems and Devices.

The introduction of MASH follows changes to the vehicle fleet, researching of real-life impact conditions and updated criteria for evaluating barrier performance. Most products tested to the superseded NCHRP Report 350 standard do not pass MASH testing. Australian State Road Agencies require MASH compliance for all new safety barrier installations.

The above-mentioned values were recorded for a post spacing of 2m centres.

Dynamic deflection is the maximum lateral displacement of the barrier during a vehicle impact. Deflection is measured from the face of the thrie-beam guardrail.

The working width is the minimum distance required to prevent an impacting design vehicle from colliding with an object behind a barrier system. This includes both the dynamic deflection of the barrier and the extra width to allow for the roll (vertical rotation) of an impacting vehicle.

Working width is an important design consideration when shielding fixed hazards such as trees, sign supports or bridge piers.

The point of need (PON) is the location along the barrier system where containment and redirection of errant vehicles commences. The distance between the leading and trailing points of need is referred to as the length of need.

The MASH TL4 PON provides containment of a 10,000kg rigid truck travelling at 90km/h and 15 degrees. The MASH TL4 PON for RAMSHIELD® High Containment is 9.5m downstream of the asymmetric transition.

The MASH TL3 PON provides containment of a 2270kg pick-up truck travelling at 100km/h and 25°. When anchored with MSKT terminals the MASH TL3 PON is the 3rd post of the end terminal.

RAMSHIELD® High Containment has been crash tested with the top of the thrie-beam guardrail 1000mm above ground level. The thrie-beam guardrail is positioned approximately 30mm above the top of post. This is an important design consideration for vulnerable road users.

The use of an asymmetric transition is required to transition from thrie-beam to w-beam guardrail. The asymmetric transition panel is 1905mm long.

The asymmetric transition lowers the height to top of the thrie-beam rail by 200mm, making it compatible for use with RAMSHIELD® w-beam guardrail and MSKT terminals, which are installed with a rail height of 800mm above ground level.

RAMSHIELD® High Containment uses the same C-post profile as used for Australian public domain systems. The separation of the thrie-beam rail from the post is achieved by a release tab incorporated into the post. The tab controls the release of the rail within the impact zone providing stable vehicle containment and redirection with minimal vehicle roll.

The sectional strength of the C-post limits barrier deflection, an important design consideration when shielding roadside hazards.

Typically, RAMSHIELD® High Containment posts are driven directly into natural ground. There is no concrete required. The posts may also be driven directly into deep lift asphalt or installed into narrow holes drilled into rock.

No. RAMSHIELD® High Containment is installed using standard thrie-beam guardrail panels and standard fasteners as per Australian state road agency designs.

A thrie-beam guardrail system provides numerous performance benefits when compared to a w-beam guardrail system including:

• Higher vehicle containment level;
• The 1m thrie-beam rail height provides improved stability for high-centre-of-gravity vehicles;
• Lower deflection values;
• Less prone to damage from nuisance impacts; and
• The thrie-beam rail provides a wider lateral catching area

A thrie beam guardrail is a triple wave shape barrier designed for high-energy vehicle impacts.