INGAL Ezy-Guard 4, Product Manual, Page: 10 / 34

Roadside Safety Barrier
10
Release 07/22b
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 different 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 4 is
dependent on the design containment level.
• Test Level 2 containment, where the design vehicle is
a 2,000kg pick-up, the minimum length of Ezy-Guard
4 between terminals is 12m.
• MASH Test Level 3 containment, where the design
vehicle is a 2,270kg pick-up, the minimum length of
Ezy-Guard 4 is 20m between terminals.
• NCHRP-350 Test Level 4 containment, where the
design vehicle is a 8,000kg truck, the minimum length
of Ezy-Guard 4 is 56m in between terminals
7.3 Sequence of Work
Where Ezy-Guard 4 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 4 shall be constructed in the configuration
as detailed in Ingal Civil Products’ drawings. This is the
configuration in which the system has been crash
tested. No modifications shall be made to the system
unless verified by Ingal Civil Products.
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 in accordance with Table 4.
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 4 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-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 4 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.
When installed in standard soil, the 873mm embedment
depth of the Z-post is sufficient for installation up to the
rounding point on 2:1 embankment slopes.
Installations within 300mm from the hinge point should
be considered within the requirements of Section 6.3
and the road controlling authority Extended Design
Domain requirements.
7.5.2 Weak Soil
Ezy-Guard 4 has been evaluated for installation in weak
soil in accordance with AASHTO standard specification
for ‘Fine Aggregate for Hydraulic Cement Concrete,”
designation M 6.
When installed in weak soil, the 873mm embedment
depth of the Z-post is sufficient 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 1,050mm. A longer Z-post is available
from Ingal for these applications. Installations in close
proximity to a batter slope should be in accordance
with Section 6.3 and the road controlling authority
extended design domain requirements..