Sentry Thrie-Beam
Sentry Thrie-Beam Guardrail has advanced the containment level of public domain thrie-beam guardrail by introducing innovative technology into the thrie-beam guardrail release mechanism. The additional corrugation provided by the thrie-beam rail combined with the higher mounting height, stiffens the barrier and improves its ability to contain larger vehicles.
Crash Test Evaluation
Barrier Configuation
Vehicle Type
Vehicle Mass
impact speed
impact angle
impact energy
Dynamic Deflection
Posts at 2m Centres
Posts at 2m Centres
Barrier Configuation
Posts at 2m Centres
Vehicle Type
Vehicle Mass
impact speed
impact angle
impact energy
Dynamic Deflection
Barrier Configuation
Posts at 2m Centres
Vehicle Type
Vehicle Mass
impact speed
impact angle
impact energy
Dynamic Deflection
Installation
Post Type
Standard Post Spacing
Post Embedment
Beam Type
System Height
Driven Post
2.0 m
960 mm
Thrie-Beam
1050 mm
Post Type
Driven Post
Standard Post Spacing
2.0 m
Post Embedment
960 mm
Beam Type
Thrie-Beam
System Height
1050 mm
Product Features
MASH TL4 Compliant
Containment of a 10,000 kg rigid truck travelling at 90 km/h and 15 degrees.
Innovative Design
Controlled release of the thrie-beam guardrail during a vehicle impact.
Narrow System Width
No blocking pieces required reducing the system width to just 200 mm.
Durable Solution
Hot dip galvanised components.
Product Gallery
Downloads
Product Manual
Product Data Sheet
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Frequently Asked Questions
How does Sentry Thrie-Beam work?
Sentry Thrie-Beam achieves a 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 deformable washer securing the thrie-beam guardrail to the post. Sentry Thrie-Beam uses standard thrie-beam guardrails and standard guardrail fasteners.
What is the containment level of Sentry Thrie-Beam?
Sentry Thrie-Beam has been crash tested in accordance with MASH Test Level 3 (TL3) and MASH Test Level 4 (TL4).
What is the MASH TL3 impact performance of Sentry Thrie-Beam?
The maximum dynamic deflection of Sentry Thrie-Beam during MASH TL3 crash testing was 1.45 m. The working width of Sentry Thrie-Beam during MASH TL3 crash testing was 1.53 m. These results were recorded during an impact with a 2270 kg pick-up truck travelling at 100 km/h and 25 degrees.
What is the MASH TL4 impact performance of Sentry Thrie-Beam?
The maximum dynamic deflection of Sentry Thrie-Beam during MASH TL4 crash testing was 1.53 m. The working width of Sentry Thrie-Beam during MASH TL4 crash testing was 2.80 m. These results were recorded during an impact with a 10,000 kg rigid truck travelling at 90 km/h and 15 degrees.
What is the difference between Dynamic Deflection and Working width?
Dynamic deflection is the maximum lateral displacement of the barrier during a vehicle impact and is typically specified when shielding batter slopes, culverts or where the hazard is low enough that it does not interfere with the possible vehicle intrusion into the area behind a barrier. 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 above-ground fixed hazards such as trees, sign supports or bridge piers.
What is the installed height of Sentry Thrie-Beam?
The thrie-beam guardrail is positioned at a height of 1050 mm above ground level.
What is the standard post embedment depth when installing Sentry Thrie-Beam?
The standard post embedment depth for the installation of Sentry Thrie-Beam is 960 mm.
Can Sentry Thrie-Beam posts be installed on a concrete strip footing?
Yes. In circumstances where an underground service or obstruction prevents the Sentry Thrie-Beam system from being installed with posts driven into the ground, a concrete strip footing may be constructed to accommodate posts with base plates. Please refer to the Product Manual and Drawings for design guidance.
Can Sentry Thrie-Beam be directly connected to a concrete barrier?
Wherever it is necessary to join an installation of Sentry Thrie-Beam to a rigid barrier, including a bridge parapet, the public domain Austroads SBTA 21-005 Transition provides a smooth, snag-free connection by gradually increasing the stiffness of the system reducing the potential for vehicle pocketing. Please refer to the Product Manual and Drawings for design guidance.
Can Sentry Thrie-Beam be installed with a motorcycle protection barrier?
Yes. Sentry Thrie-Beam may be installed with RiderPro which is positioned beneath the thrie-beam guardrail and prevents a dismounted motorcyclist from contacting the supporting posts of the guardrail barrier. The RiderPro spring brackets attach directly to the posts and absorb the impact energy of the sliding rider. Please refer to the Product Manual and Drawings for design guidance.
