valmont Ezy-Guard HC, Product Manual

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Release 08/21
High-Containment Roadside Safety Barrier
10
HIGHWAY
7.2 Minimum Length Requirements
There are two geometric methods used to determine the likely
trajectory of a vehicle that leaves the road in the vicinity of a
roadside hazard and the minimum length of barrier required
to protect from this hazard.
The most common method is the run-out length method and
an alternative is a method based on angle of departure.
Prior to design or installation, designers should consult the
relevant road controlling authority to establish the local
jurisdictional practice as the methods may result in dierent
lengths. Both methods are detailed in the Austroads Guide
to Road Design – Part 6.3.
For instances where geometric constraints limit the
installation of the recommended length under the above
design methods, the absolute minimum length of minimum
length of need for Ezy-Guard HC is dependent on the design
containment level. For measurement of minimum installed
length, refer Figure 6 below.
• MASH Test Level 3 containment, where the design vehicle
is a 2,270kg pick-up, the minimum length of Ezy-Guard
HC is 20m.
• MASH Test Level 4 containment, where the design vehicle
is a 10,000kg truck, the minimum length of Ezy-Guard HC
is 26m.
7.3 Sequence of Work
Where Ezy-Guard HC is being constructed on a road open
to traffic, it is recommended that the work commence at the
end closest to the approaching traffic. Leading terminals and
transitions shall be commissioned at the earliest practical time.
7.4 Modifications
Ezy-Guard HC shall be constructed in the configuration
as detailed in Valmont Highway’s drawings. This is the
configuration in which the system has been crash tested. No
modifications shall be made to the system unless verified by
Valmont Highway.
Flame cutting of rails or posts is not permitted. Saw cutting
and drilling is permitted in the event that a post is to be
installed at an irregular spacing and/or rock is encountered
and the post embedment depth has been modified.
Any modification carried out after fabrication will require
repair to the galvanized coating. This is undertaken by
applying two coats of an organic zinc rich epoxy paint
complying with AS/NZS 3750.9. This is to be applied to the
repair areas in two coats. Each coat shall have a minimum
dry film thickness of 50 μm.
7.5 Soil Requirements & Embedment Depth
The Z-post is designed to yield by bending near ground level
during impact. Provided the post is embedded in material
that allows this failure mechanism to be replicated, the Ezy-
Guard HC functionality will be retained. The Z-posts will
provide lateral resistance until the impacting vehicle causes
deformation of the posts. At this point the Ezy-HC-Carriages
will provide a controlled release of the rail from the Z-posts
resulting in safe vehicle containment and redirection.
7.5.1 Standard Soil
Ezy-Guard HC has been evaluated for installation in standard
soil in accordance with AASHTO standard specifications for
‘Materials for Aggregate and Soil Aggregate Subbase, Base
and Surface Courses,’ designation M 147.
Change to:
When installed in weak soil, the 1,030mm embedment depth
of the Z-post is sucient for installation up to 500mm of the
rounding point on 2:1 embankment slopes. If installation
is required within 500mm of the rounding point, the post
embedment depth is required to be increased to 1,350mm.
A longer Z-post is available from Ingal Civil for these
applications.
For a TL4 containment level, installations within 1.7m from
the hinge point should be considered within the requirements
of the road controlling authority Extended Design Domain
requirements.
Figure 6. Minimum length measurement