|  General
Kriblok components are transported on timber pallets
for ease of offloading and efficient site distribution.
It is normal to erect Kriblok walls on adequate concrete
strip foundations. Having established the alignment
of the wall by positioning the first course, wall erection
proceeds rapidly and can be simply checked for line
and level with stringlines. The infill/backfill procedure
should be completed course by course as the wall is
erected.
Individual cribs should be infilled and the whole structure
backfilled with a well graded angular material as Type
B in accordance with Specification for Highway Works:
Volume 1: 1991: Table5/5.
1. Foundation
The concrete foundations for the proposed wall should
be set out and cast in accordance with the Engineer’s
drawings and specification. A low slump concrete (max.
40mm) should be used to achieve the required batter.
A float or carefully tampered finish is recommended
and the profile should be checked with a batter board
appropriate to the inclination of the wall.
2. Wall Erection (Straight Walls)
The outer row (first course) of stretchers should be
placed to the correct line and bedded to level on a
dry sharp sand/cement mix (max. 25mm thickness). Each
stretcher must be close butted to the next.
The inner row (first course) of stretchers should be
bedded as above. The spacing of stretchers should be
in accordance with the system being used. As these units
are placed, the profile should be checked with the batter
board. Subsequent rows of base course stretchers for
multi-crib construction should be placed as above.
The first header unit should be positioned at the end
of the wall, fully bearing on the front and second row
of stretchers. Subsequent headers should be positioned
at the correct centres and centrally over the joint
between the stretchers such that the face of the headers
and the joint between the stretchers form a vertical
line, front and rear thus ensuring correct bearing for
all the wall units.
Once placed, the headers should be checked for line,
level and profile. The next course of stretcher units
should now be placed, ensuring that the joints line
up vertically with previous courses. A land drain should
now be installed at the rear of the wall in accordance
with the Engineer’s drawings and specification.
The infill and backfill operation can now commence.
 3.
Wall Erection (Multi Cribs)
A multi thickness crib may be required to cater for
high walls or where exceptional superimposed loads are
met.
The headers of each back section are placed on the
rear stretcher of the wall in front, adjacent to the
front headers.
4. Wall Erection (Radius Walls)
Before commencing the erection of radius walls
the correct radius line should be clearly marked onto
the concrete foundation corresponding to the base of
the front on the wall. It is important to note that
all stretcher units within a radius wall construction
will need to be cut on site to the required lengths.
On an internal radius wall the longest (full length)
stretchers will be the top rear course. Correspondingly,
the shortest stretchers will be the base front course.
On an external radius wall the longest (full length)
stretchers will be the base front course, and the shortest
the top rear course.
Once the base front course stretcher have been cut
to the required length these should be place and bedded
on a sharp sand/cement mix to correct line and level.
Alignment can be established using a string line secured
to the centre setting out point of the radius and clearly
marked to the correct radius. This will allow the position
and alignment to be established at the end of each stretcher
unit. The rear course of stretchers can be similarly
positioned and aligned. The first course of header units
should be positioned centrally over the butt tight stretcher
joints and the alignment checked to the correct tangent
using the string line.
The required cut length of the second course of front
and rear stretcher units can now be established by physical
measurement centre to centre on the upper face of the
header units at the stretcher bearing point position.
As the erection progresses the wall should be continually
checked for correct profile and alignment using the
string line, a batter profile together with a spirit
level and straight edge to check that the header units
are vertically aligned.
N.B. Where radius walls are to be
constructed on stepped foundations it is important to
set the wall out and commence erection from the lowest
foundation level.
 5.
Wall Erection (Corners)
a) External Corners
When setting out an external corner the bases front
stretcher at the corner position should be maintained
at full length with just the appropriate end cut to
a 450 mitre.
The rear base course of stretchers can then be cut and
mitred to the required length. As with standard header
units, the corner header must be accurately positioned
over the mitred stretcher joints. The required length
of the second and subsequent courses of stretcher units
adjacent to the corner can be established by physical
measurement ensuring that the correct wall batter is
maintained.
b) Internal Corners
Taking due account of the height of wall to
be constructed calculations should be carried out to
establish the cut length of the base stretchers adjacent
to the corner assuming a full stretcher length on the
top front course. As with external corners once the
base stretchers and first corner unit have been correctly
positioned the length of the second and subsequent stretcher
units can be determined by physical measurement. It
should be noted that where corners are to be built in
walls of double crib construction that corner units
are only used for the front crib. Where corners are
to be built in walls of treble crib construction corner
units are used on the front and rear cribs.
For both internal and external corners it may be necessary
depending upon the height and configuration of the wall,
to introduce additional header and cut stretcher components
to maintain satisfactory bonding and the full integrity
of the construction. Further details on corner construction
can be provided on a site specific basis.
6. Infill and Backfill
The infill material should be carefully placed, as excess
discharge from a machine bucket may displace wall units.
The material should be placed and compacted to ensure
uniformity of filling and support to the units, taking
care to avoid displacement of the wall units. The backfill
material should be placed in layers determined by the
nature of material used, and compacting should be carried
out as detailed in the specification. Care must be taken
to avoid displacement of wall units.
As the infilling and backfilling progresses, the wall
units should be checked for line, level and batter.
Subsequent courses of headers and stretchers can be
placed, with infilling and back filling taking place
course by course.
When the wall is complete the top front row of stretchers
can be dry laid, or secured with a bed and haunch of
sand and cement mortar.
7. Landscaping
Terraced walls may be used to avoid complex construction
of high walls, where conditions are suitable. It is
important that the horizontal distance between any two
walls is greater than the height of the lower of the
two walls.
In addition, care must be taken to avoid the creation
of slip planes.
NOTES
It is essential that all cut ends of units are sealed
to prevent the ingress of moisture and corrosion of
the reinforcement steel. The material recommended for
this is “Sikatop-seal 107” applied strictly
in accordance with the manufacturers recommendations.
(Details can be supplied on request).
It is most important that during construction of the
wall it is not subjected to any undue loading for which
it is not designed to withstand.
The Company’s policy is one of continuous development
and production improvement. Information contained in
this page is subject to alteration without notice.
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