February 2021 |
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Product & Installation Manual: Sentry Barrier™
KEEPING
NZ SAFE
Introduction
The Sentry Barrier™ is a roadside W-Beam
guardrail system suitable for containing,
redirecting and shielding vehicles from roadside
obstacles. The barrier has been designed and
tested to meet the evaluation criteria of MASH
Test Level 3 (TL-3) for a longitudinal barrier. This
is the current state of the art performance criteria,
exceeding the requirements of NCHRP 350 TL-3.
The Sentry Barrier™ has an initial installation
height of 800 mm to the top of the rail, providing
the system with the ability to withstand numerous
road surface overlays without the need to relevel
of lifting of the barrier. The Sentry Barrier™ can
be installed with an approved energy absorbing
terminal end on the approach end, however it
is recommended that an approved tangential or
flared MAX-Tension™ End Terminal be used for
optimal performance.
The rounded edges to the Sentry Barrier™ Post
and closed shape on the approach direction
provide increased protection for vulnerable
road users. The compact Sentry Barrier™ posts
are easy to drive into all soil types and provide
increased resistance to rotation in the soil when
impacted. Unlike other systems on the market,
any damage caused to the top of the posts or to
the rail mounting points during installation will not
affect the performance of the system.
The connection system between the rail and
posts is formed using conventional fasteners
providing it with the greatest tolerance of any
system on the market. If the connection is
damaged in any way it can be easily replaced
without replacing the posts allowing for simpler
installations and repairs. The Sentry Barrier™ is
installed quickly using conventional installation
tools and equipment.
System Overview
The Sentry Barrier™ is designed to provide
acceptable structural adequacy, minimal
occupant risk and safe vehicle trajectory as
required by the latest in safety standards,
AASHTO MASH 09 TL-3. 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.
The requirements of MASH 09 TL-3 are so
stringent that the system is required to absorb
more energy during the impact than the out-
dated NCHRP 350 standard TL-4.
When impacted by an errant vehicle, the Sentry
Barrier™ 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
W-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™ are:
System width
201 mm
Height to top of rail
800 mm
Height to top of post
790 mm
Post weight
13.7 kg
Post length
1.64 m
Post spacing
1.905 m
MASH TL3.10 dynamic deflection
1.02 m
MASH TL3.11 dynamic deflection
1.59 m
