Note: Descriptions are shown in the official language in which they were submitted.
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TITLE
"A PILING WRAP"
FIELD OF THE INVENTION
The invention resides in a piling wrap. In particular, the piling
wrap is used to repair and strengthen structural support members.
BACKGROUND OF THE INVENTION
The infrastructure for the transportation of people, goods and
services that was developed and rapidly expanded after the Second World
War is now reaching a critical age with widespread signs of deterioration and
inadequate functionality. Deficiencies in the existing transportation
infrastructure, such as bridges, range from those related to wear,
environmental deterioration, aging of structural components, to use of
substandard materials in initial construction and inadequate maintenance. It
is becoming increasingly apparent that deteriorating infrastructure systems
have a tremendous impact on society in terms of socio-economic losses
resulting from delays and accidents.
Repair and rehabilitation systems based on conventional
materials such as steel and concrete have significant limitations due to
weight, durability and installation difficulties. As a result, fibre composite
systems are increasingly being considered for use in rehabilitation. Fibre
composites combine high strength and stiffness-to-weight ratios, corrosion
resistance, environmental durability and inherent tailorability. Furthermore,
the ease of application of fibre reinforced plastic composites makes them
extremely attractive for use in civil infrastructure repair and
rehabilitation,
especially in cases where weight, space or time restrictions exist.
Fibre composite systems have found widespread use for the
repair, strengthening and retrofit of columns. These systems generally take
the form of jackets/wraps around the column to induce lateral confinement in
the column as it expands laterally due to high axial compression strains or
internal pressure build-up due to alkaline aggregate related problems. Fibre
composite jacketing techniques have been shown to have performance
capabilities comparable to steel casings at comparable cost.
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Different types of composite jacketing systems have been
developed to increase the speed of installation of jackets, reduce
maintenance and improve durability. Based on the method of installation,
these can be differentiated into five basic types:
1: wet lay-up systems using fabric, tape or individual fibre tows;
2: prepreg systems in the form of tape or fabric;
3: prefabricated shells;
4: systems based on on-site resin infusion;
5: prefabricated strips.
The wet lay-up systems afford considerable flexibility but there
are serious concerns related to quality control and cure of the resin mix and
fibres on site for above water applications.
The use of prepreg systems potentially provides a higher level
of quality control but necessitates strict adherence to a specific cure
schedule at elevated temperatures. This can cause serious problems if the
substrate concrete is very moist resulting in water vapour driven blistering.
In the case of prefabricated shells, the sections are
prefabricated in a factory and adhesively bonded in the field to form the
jacket. This process affords a high level of material quality control due to
controlled factory-based fabrication of the shells. However, the effectiveness
of the system rests on the ability of the adhesive to transfer load, and hence
is dependent on the integrity of the bond constructed in the field. The
substrate has to be clean and dry to obtain good adhesion which limits this
approach to special applications only.
Systems based on resin infusion are costly to perform on-site
and the effectiveness of prefabricated strips is limited because they do not
confine the column fully.
Most jacket systems are very effective for round columns but
have great difficulty providing confinement for square and rectangular
columns. Due to the straight sections between corners, the composite does
not actually confine the column if just applied to the flat surface. In fact,
if
used in this manner, reinforcement fibres are often loose and unable to
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provide any confinement. In addition, the corners of rectangular columns
generally need to be rounded to decrease the chance of fibre fracture due to
stress concentration induced through the sharp edge, adding significantly to
on-site costs.
OBJECT OF THE INVENTION
It is an object of the invention to overcome or alleviate one or
more of the above disadvantages or provide the consumer with a useful or
commercial choice.
It is a preferred object of the invention to enable
repair/strengthening of columns without having to rely on on-site curing of
polymer resin systems.
It is a further preferred object of this invention to
repair/strengthen columns with a prefabricated fibre composite shell system
that does not rely on an adhesive joint between the column and the shell to
transfer the loads.
It is a still further preferred object of the invention to enable
repair/strengthening of columns with minimal cleaning of the column surface.
It is a still further preferred object of the invention to provide
excellent confinement to any shape of column such as circular, rectangular
or hexagonal.
It is a still further preferred object of the invention to enable
repair/strengthening of columns above and below water using the same
system.
It is a still further preferred object of the invention to
significantly reduce the cost and effort associated with the
repair/strengthening of columns under water.
It is a still further preferred object of the invention to provide a
repair/strengthening system with tailorable structural properties.
SUMMARY OF THE INVENTION
In one form, although not necessarily the broadest or only form,
the invention resides in a piling wrap comprising:
a shell that extends around a support member, the shell having at
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least two ends and;
a plurality of inter-engaging fingers located on the each of the ends of
said shell;
the shell is movable between an unlocked position where the inter-
engaged fingers are not engaged and a locked position where the inter-
engaging fingers are engaged;
the at (east two of the fingers extend inwardly toward an interior
surface of the shell when infer-engaging angers are in the locked position"
wherein the at least two of the fingers are located at different orientations
with respect to each other .
The piling wrap can be made using epoxy, vinylester or
polyester resin and glass and/or carbon reinforcement. Preferably, the piling
wrap is resilient.
Preferably, the inter-engaging finger and the shell are integrally
formed.
The shell may be arcuate in shape. However, it is envisaged
that the shell may be of other shapes. At least one handle may be located
on the shell to allow the shell to be easily handled.
Normally the shell has only two ends. However, it is envisaged
that the shell may have four or six or eight ends.
Sealing strips may be attached to each of the fingers.
Normally, the sealing strips are made of rubber or foam.
The interior surface of the shell is coated with an interface.
The interface is normally in the form of stone or sand. Normally, gravel is
used. The gravel may be formed from basalt.
The interface is usually glued to the inside of the shell using an
adhesive such as epoxy. Preferably, only one side of the interface is
adhered in the adhesive with at least one other side being left exposed so
that it can bond to a cement-based grout.
The inter-engaging fingers are preferably coated with interface
on both sides to integrally lock them into the cement-based grout.
A flange may be located at a top andlor bottom of the piling
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wrap. The flange normally has radially extending splits.
f n another form, the invention resides in a method of installing a
piling wrap to form reinforcing a support member, the method including the
steps of:
5 locating at least one piling wrap around the support member;
the piling wrap having a shell that extends around a support member, the
shelf having two ends and a plurality of inter-engaging fingers located on
each end of said shell, the shell movable between an unlocked position
where the inter-engaged fingers are not engaged and a locked position
where the inter-engaging fingers are engaged; the at least two of the fingers
extend inwardly toward an interior surtace of the shell when inter-engaging
fingers are in the locked position, wherein the at least two of the fingers
are
located at different orientations with respect to each other .
engaging the inter-engaging fingers so that the piling wrap is in
a locked position; and
introducing cementitious material between the piling wrap and
the support member.
Normally ground is removed adjacent a bottom of the support
member to ensure that when the piling wrap is placed onto the ground, a
seal is formed.
Once the fibre composite shell has been snapped around a
support member a number of an external straps are applied to the outside of
the piling wrap to hold the piling wrap in place whilst the cementitious
material is introduced into the piling wrap. The straps may carry the
hydrostatic grout pressure until the cementitious material has set. Once the
cementitious material has set, the straps may be removed and re-used.
The cementitious material may be pumped into a bottom part of
each of the pilling wraps via an inlet hole. Once one piling wrap has been
filled with cementitious material, the next piling wrap may be filled using an
inlet hole located at a bottom part of the piling wrap.
A temporary intermediate sealing ring may be located between
different piling wraps. This temporary intermediate sealing ring may be
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removed and re-used once the cementitious material has set. A temporary
top sealing ring has been developed for a top piling wrap to seal the top
against the top of the support member.
In yet another form, the invention resides in a support member
reinforcement system comprising:
a support member that supports a load;
a piling wrap having
a shell that extends around the support member, the shell
having at least two ends and;
a plurality of inter-engaging fingers located on each end of said
shell;
the inter-engaging fingers being inter-engaged in a locked
position; and
a cementitious material located between the support member and the
piling wrap;
wherein the inter-engaging fingers extend into the cementitious
material.
The support member is typically deteriorated.
The piling member may have a shell that is slightly oversize
when compared to the support member. There may be a space of
approximately 75mm between the support member and the piling wrap.
Usually, the cementitious material is a cement-based grout.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention, by way of example only, will now
be described with reference to the accompany drawings in which:
FIG. 1 is a piling wrap in an unlocked position according to an
embodiment of the invention;
FIG. 2 is a partial perspective view of the piling wrap of FIG.-1
in a locked position;
FIG. 3 is a front view of piling wraps applied to an underwater
column;
FIG. 4 is a partial side s~tionai view of two piling wraps joined
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together;
FIG. 5 is a cross-sectional view of a piling wrap applied to an
underwater column shown in FIG. 3;
FIG. 6 is a perspective view of a skirt; and
FIG. 7 is a partial front view of a piling wrap applied to an
underwater column using the skirt of FIG. 8.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a piling wrap 10 used to repair and strengthen a
support member of a structure such as a building or a bridge. The piling
wrap 10 had been designed so that it is able to be used for the repair and
strengthening of an underwater support member such as a column 5 as used
an bridges. However, the piling wrap 10 may be used for above-ground
columns.
The piling wrap 10 consists of an arcuate shell 20 having inter-
engaging fingers 30 located at the ends of the arcuate shell 20. The arcuate
shell 20 and inter-engaging fingers 30 are formed entirely of fibre-reinforced
plastics with the inter-engaging fingers 30 being obtained by cutting or
casting the arcuate shell 20 at its ends.
The inter-engaging fingers 30 are able to be engaged so that
the shell forms a substantially cylindrical shape. When the inter-engaging
fingers 30 are locked together, the fingers extend inwardly towards the
interior surface of the shell 20 as shown in FIG. 2. The fingers on each end
of the shell are located at different angular orientations.
The interior surtace of the shell 20 is coated with gravel in the
form of basalt 40 or similar aggregate. The basalt 40 is adhered on the
interior surface 21 of the shell 20 using an adhesive such as epoxy. Only one
side of the basalt 40 is stuck to the shell 20 by the adhesive with at (east
one
other side being left exposed so that it can bond to a cement-based grout. It
should be appreciated that other stones may be used instead of basalt.
The inter-engaging fingers 30 are coated with the basalt 40 on
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both sides of the fingers 30 to lock them to the cement-based grout.
Rubber seating strips 31 are attached to each of the fingers 30
to form a seal when the inter-engaging fingers 30 are in the lacked position.
Handles 21 are provided on an exterior surface~of the shell to
allow the piling wrap 10 to be easily handled.
An inlet hole 22 is located through the shell 20 adjacent a
bottom of the shell 20. The inlet hole 22 allows cement-based grout to be
pumped inside the piling wrap 10.
A flange 50 is attached at the top and bottom of each
intermediate piling wrap. Each flange 50 has a plurality of radiaily extending
splits 51 that extend outwardly from the shell 20 to provide minimum rigidity.
it should be appreciated that the flange 50 is located at the top of the
bottom
piling wrap and at the bottom of the top piling wrap.
In use, a number of piling wraps 10 are located around a
column 5 as shown in FIG. 3. The piling wraps 10 are formed from
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composite fibre reinforced plastic making the piling wrap 10 resilient so that
it
can be flexed open manually to snap around the column 5. The splits 51 of
the flanges 50 allow the piling wrap to be flexed open. The weight of the
piling wrap 10 has been designed such that it can be manually handled
above and below water. The handles assist in allowing the placement of the
piling wraps 10.
To install the pilling wraps 10 around the column 5 to produced
a support member reinforcement system as shown in FIG. 3, ground 6
adjacent the base of the column is removed. A bottom piling wrap is located
within the removed area. The shell 20 is sized so that a gap is formed
between the column and the piling wrap 10. The gap is normally about
75mm. The placement of the bottom piling wrap into the removed ground
seals the gap between the bottom of the column and the piling wrap.
The inter-engaging fingers 30 are then engaged so that the
piling wrap 10 is locked around the column 5 as shown in FIG. 4. External
straps 23 made of fibre composite, nylon, steel or other material are located
around the shell to tightly force the inter-engaging fingers 30 together to
allow the rubber sealing strips 31 to seal the shell 20.
Once the bottom piling wrap is positioned, an intermediate
piling wrap is placed on top of the bottom piling wrap. A rubber sealing ring
60 is located on the between the adjacent flanges of adjacent piling wraps.
Two metal half rings 70 are located adjacent the flanges 50 of adjacent piling
wraps. Bolt holes extend through the flanges 50. Holes are then drilled
through the flanges 50 and the rubber sealing ring 60 to match the holes in
the flanges. It should be appreciated that the holes in the flanges and rubber
seal may be prefabricated.
Bolts 71 are then placed through the metal half rings 70, rubber
sealing ring 60 and flanges 50. Nuts 72 are placed on the bolts 71 and
tightened to pull the two adjacent piling wraps 10 together to provide a seal
between the adjacent piling wraps 10 as shown in FIG. 4. This process is
repeated until the entire length of the column 5 is enclosed.
A top piling member usually does not seal against a cap
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located at the top of the column 5. According, a top sealing ring 80 has been
developed to seal the top piling wrap against a column cap 7. The top
sealing ring 80 includes an inflatable bladder 81. The bladder is removably
connected to the top piling wrap and inflated to seal the piling wrap and the
column. When the sealing ring has been located on the column and the top
piling wrap, the bladder is inflated which seals the gap between the column
cap and the top piling wrap.
During installation, each piling wrap 10 is orientated around the
column so that the inlet hole 22 is located at the bottom of the shell 20.
Further, a removable platform 81 is located within each of the handles to
provide a footing to allow each piling wrap to be placed easily.
When the piling wraps 10 are positioned, cement-based grout
90 is pumped into the piling wrap 10 via inlet holes 22 to fill the gap and
complete the support member reinforcement system 100. The cement-
based grout 90 is introduced into the piling wrap until cement-based grout 60
appears at the next inlet hole 22. The pump is then removed from a lower
inlet hole and located at an upper inlet hole 22. As cement is pumped into
the piling wraps 10, the cement-based grout 90 displaces water located
within the gap through the top of the piling wrap 10. The inlet holes 22 are
swapped so that the pump used to pump the concrete only needs to displace
concrete through only a single piling wrap 10, not through all of the joined
piling wraps 10.
The cement-based grout 90 fulfils multiple roles to seal and
encase the column, to transfer load between the column 5 and the piling
wrap 10, to provide additional vertical load carrying capacity, and to lock
the
inter-engaging fingers 30 as shown in FIG. 4.
The concrete-based grout 90 will generally also form a
reasonable bond to the column 5. Surface preparation needed to obtain
such a bond is significantly less than that required for a polymer-based
adhesive. In particular, the presence of moisture, which is generally a
problem with polymer adhesives, is not a problem with the water-based
cement grout 60.
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The basalt 40 located on the interior surface of the shell 20 and
on both sides of the inter-engaging fingers 30 is a purposely designed
interface to obtain an integral bond between the fibre composite shell 20 and
the cement based grout 60. This basalt assists in holding the piling wrap 10
5 to the cement-based grout 60.
In the event that ground adjacent the column 5 cannot be
removed, a skirt shown in FIG. 6 is used. The skirt 110 is made from a
flexible geotextile and is doughnut-shaped. An inner cord 111 extends
through an inner sleeve 112 located adjacent an inner circle and with an
10 outer card 113 mending through an outer sleeve 114 located adjacent an
outer circle.
fn use, the skirt 110 is located around the column 5 with the
inner circle is located adjacent the column. The inner cord 111 is pulled fo
tighten the skirt 110 around the column 5. The bottom piling wrap is then
located around the column 5 and placed onto the skirt 110. The skirt 110 is
lifted over the piling wrap 10 and outer cord 113 tightened to hold the skirt
110 to the piling wrap. This seals the gap between the column and the piling
wrap.
The piling wrap 10 and its application to produce a support
member reinforcement system provide several advantages. Firstly, when the
cement-based grout 60 has set and the column 5 tries to expand under load
or due to alkaline aggregate effects, the internal pressure will push on the
inter-engaging finger 30 and this normal pressure will make it harder for the
fingers to pull out of the cement-based grout 60. The more internal pressure,
the harder it is for the fingers 30 to pull out as they are locked together
and
due to fingers at each end of the shell being at different angular
orientations.
In other words, the inter-engaging fingers 30 become "self-locking" under
internal pressure.
Secondly, due to the use of cement-based grout 60, the piling
wrap 10 can be used on a wide range of column shapes.
Lastly, the fibre architecture of the composite piling wraps 10
can be purposely designed to provide confinement andlor additional vertical
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toad carrying capacity.
It should be appreciated that various other changes and
modifications may be made to the embodiment described without deparking
from the spirit or scope of the invention.
Amended Sheet
IPI;A/AU
