November 2020 |
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Product & Installation Manual: Sentry Barrier™ TL-4 Thrie-Beam System
KEEPING
NZ SAFE
System Overview
The Sentry Barrier™ TL-4 Thrie-Beam System
is designed to provide acceptable structural
adequacy, minimal occupant risk and safe
vehicle trajectory as required by the latest in
safety standards, AASHTO MASH 16 Test Level
4 (TL4). This standard requires the system to be
independently evaluated with full scaling testing
using 1,100 kg and 2,270 kg vehicles traveling
at speeds of 100 km/hr and impacting the
system at an angle of 25 degrees, as well as a
10,000 kg truck travelling at 90 km/hr impacting
the system at an angle of 15 degrees. The
requirements of MASH 16 TL4 are so stringent
that the system is required to absorb more
energy during the impact than the out-dated
NCHRP 350 standard Test Level 4 (TL4).
When impacted by an errant vehicle, the Sentry
Barrier™ TL-4 Thrie-Beam System will redirect
the vehicle along the face of the barrier system,
bringing it to a controlled stop. The system has
been developed to produce no debris during an
impact, with all posts designed to remain firmly
located in the soil and the connection details
to remain attached to the rail. Repair of the
system is completed by removing and replacing
any bent or damaged Thrie-Beam and posts
impacted accordingly.
Any posts with damaged connections can be
repaired by replacing the connection hardware
only, reducing the need to remove posts and
repair damaged ground.
Key specifications for the Sentry Barrier™ TL-4
Thrie-Beam System are:
The minimum Length of Need (LON) of the
Sentry Barrier™ TL-4 Thrie-Beam System is
dependent on the posted speed limit. Please
refer to state roading authority approval
letters for local minimum length requirements.
However, a minimum length of need for a two-
way road with a posted speed limit of 100 km/
hr with a clear zone of approaching traffic is
recommend as 86 m, excluding terminal ends.
The Sentry Barrier™ TL-4 Thrie-Beam System
systems rails and posts are manufactured from
hot-rolled steel flat products in accordance
with AS/NZS 1594 and hot-dip galvanised in
accordance with AS/NZS 4680 with an average
minimum coating thickness of 35 microns.
All galvanising is undertaken after fabrication
is completed to ensure no surfaces are left
untreated.
System width
200 mm
Height to top of rail
1050 mm
Height to top of post
1040 mm
Post weight
20.5 kg
Post length
2.00 m
Post spacing
2.00 m
MASH TL4.10 dynamic deflection
(1,100 kg vehicle)
1.06 m
MASH TL4.11 dynamic deflection
(2,270 kg vehicle)
1.45 m
MASH TL4.12 dynamic deflection
(10,000 kg vehicle)
1.53 m
