valmont Ezy-Guard HC, Руководство по эксплуатации продукта

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Release 08/21
High-Containment Roadside Safety Barrier
11
HIGHWAY
1kN Force
700mm
Embedded Z-Post
Ground Level
Displacement
less than 1mm
1kN Force
700
mm
Embedded Z-Post
Ground Level
Displacement
less than 1mm
7.6 Post Pullover Test
In the event that the soil type cannot be verified, the
suitability of the post foundation can be established through
a post pullover test.
This is undertaken by applying a 1kN load to the post,
700mm above ground level. The load is applied prior to the
attachment of the rail. Displacement at the base of the post
shall not exceed 1mm whilst the load is applied.
An alternative post pull over test can be achieved via a
more destructive means, whereby a load of 1.2 tonnes is
applied to the test post at a height of 700mm. This loading
approximates the probable capacity of the post and should
be able to be maintained with minimal rotation of the post
in the soil. At the completion of the testing the post should
be removed from the test location and should not be used in
the installation.
7.7 Posts on Base Plates
In the event that the Z-post cannot be installed to the required
in-ground depth, the use of a base plate mounted on a suitable
foundation can be adopted. Posts on base plates are typically
used at culvert locations, and in areas where underground
services restrict posts from being driven into the ground.
Refer to Valmont Highway drawings for the installation of
posts on base plates base plates and to your local Valmont
representative for appropriate footing design conditions.
7.8 Z-Posts in Rock
Traditional guardrail posts are designed to yield in the
surrounding soil and their placement in rock or concrete is
problematic. Restraining the traditional posts by setting them
in narrow holes drilled into rock, setting them in concrete or
placing a mowing strip around the posts can lead to a failure
of the system to safely contain and redirect the errant vehicle.
The specially engineered Z-post dissipates energy by yielding
through bending near ground level. This means that typical
recommendations for the installation of a traditional guardrail
post in rock are not applicable to the Z-post. When rock is
encountered, the installation guidelines as detailed in Table
5 are applied. If required the bottom of the post may be cut
onsite by a disc grinder or equivalent steel cutting tool. A
corrosion resistant treatment will need to be applied to the
freshly cut surface, Valmont recommend a Zinc metal spray in
accordance with section 7.4.
7.9 Non-Standard Post Spacing
Occasionally, an underground services or obstruction may
prevent a post from being installed at the recommended
spacing. In these instances, there are a number of options:
• Ommit the post and leave a 4m gap. This will result in an
11% increase in deection if impacted in that location. For
bidirectional trac, this increase in deection is applicable
for 4m upstream and downstream of the omitted post. A
single post omission is permissible for no more than one
location in 30m of Ezy-Guard HC.
• If the underground conict is short in length, the post can
be moved 1m upstream or downstream from the original
position. Special rails are available from Ingal with slots
at 1m intervals. Alternatively, the rail can be drilled to take
the M16 carriage bolt. The drilled hole should have the
galvanized coating repaired in accordance with section
7.4.
• A concrete foundation can be installed and a post on
baseplate can be anchored to the foundation. Refer
section 7.7 for further details.
7.10 Delineation
A specially designed delineator is attached to the Z-post.
Typically, delineation is arranged so that drivers approaching
from either direction will see only;
• Red retro-reflectors on their left;
• White retro-reflectors on their right
on two-way carriageways; and
• Yellow retro-reflectors on their
right on one-way carriageways and
medians separating traffic in opposing
directions
The spacing of delineators is dependant
upon driver line of sight. As a general rule
delineators are provided for installation
every 20m on straight alignments.
Installation on curves will require a
closer spacing dependant upon the
radius of the roadway.
Figure 7: Z-Post Pullover Test