WO2005026450A1

WO2005026450A1 - A piling wrap

Info

Publication number: WO2005026450A1
Application number: PCT/AU2004/001249
Authority: WO
Inventors: Gerardus Maria Van Erp; Timothy John Heldt; Craig Leslie Cattell; Darren James Browne; Roy Marsh
Original assignee: The University Of Southern Queensland
Priority date: 2003-09-15
Filing date: 2004-09-15
Publication date: 2005-03-24
Also published as: CA2539163A1; EP1668191A1; EP1668191A4

Abstract

A piling wrap (10) having a shell (20) that extends around a support member (5), the shell (20) having two ends, and a plurality of inter-engaging fingers (30) located on each end of said shell (20); wherein the shell (20) is movable between an unlocked position where the inter-engaged fingers (30) are not engaged and a locked position where the inter-engaging fingers (30) are engaged.

Description

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. 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 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 least two ends and; a plurality of inter-engaging fingers located on the each of the ends of said shell; wherein 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 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. Preferably, when inter-engaging fingers are in the locked position, the fingers extend inwardly toward an interior surface of the shell. 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 and/or bottom of the piling wrap. The flange normally has radially extending splits. In 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: locating at least one piling wrap around the support member; 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 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. 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, byway 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 sectional view of two piling wraps joined 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. 6. 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 on 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 interior surface 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 least 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 both sides of the fingers 30 to lock them to the cement-based grout. Rubber sealing strips 31 are attached to each of the fingers 30 to form a seal when the inter-engaging fingers 30 are in the locked 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 radially 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 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 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. 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 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 outer cord 113 extending through an outer sleeve 114 located adjacent an outer circle. In 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 to 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. 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 and/or additional vertical load carrying capacity. It should be appreciated that various other changes and modifications may be made to the embodiment described without departing from the spirit or scope of the invention.

Claims

CLAIMS:

1. A piling wrap comprising: a shell that extends around a support member, the shell having at least two ends and; a plurality of inter-engaging fingers located on each end of said shell; wherein 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.

2. The piling wrap according to claim 1 wherein the piling wrap is produced using fibre reinforced plastic contain a resin and a reinforcement fibre.

3. The piling wrap of claim 2 wherein the resin is chosen from the selection of epoxy, vinylester or polyester.

4. The piling wrap of claim 2 wherein the fibre is chosen from the selection of glass and/or carbon reinforcement.

5. The piling wrap of claim 1 wherein the piling wrap is resilient.

6. The piling wrap of claim 1 wherein the inter-engaging finger and the shell are integrally formed.

7. The piling wrap of claim 1 wherein the shell is arcuate in shape.

8. The piling wrap of claim 1 wherein the piling wrap includes at least one handle.

9. The piling wrap of claim 1 wherein when inter-engaging fingers are in the locked position, the fingers extend inwardly toward an interior surface of the shell.

10. The piling wrap of claim 1 wherein sealing strips are attached to each of the fingers.

11. The piling wrap of claim 1 wherein an interior surface of the shell is coated with an interface.

12. The piling wrap of claim 1 wherein the interface is usually glued to the inside of the shell using an adhesive.

13. The piling wrap of claim 1 wherein the inter-engaging fingers are coated with an interface.

14. The piling wrap of claim 1 wherein a flange is located on the piling wrap.

15. The piling wrap of claim 14 wherein the flange has a plurality radially extending splits.

16. A method of installing a piling wrap to form reinforcing a support member, the piling wrap having a shell that extends around a support member, the shell 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 method including the steps of: locating at least one piling wrap around the support member; engaging the inter-engaging fingers so that the piling wrap is in a locked position; and introducing cementitious material between the piling wrap and support member.

17. A method of claim 16 further including the step of removing ground adjacent the support member.

18. The method of claim 16 further including the step of locating a skirt around a support member and a piling wrap.

19. The method of claim 16 further including the step of applying at least one external strap to the outside of the piling wrap.

20 The method of claim 16 further including the step of locating at upper piling wrap above a lower piling wrap.

21. The method of claim 20 further including the step of locating a sealing member located between the piling wraps.

22. The method of claim 20 further including the step of joining the upper piling wrap and lower piling wrap.

23. The method of claim 17 further including the step of introducing cementitious material into the pilling wrap via an inlet hole.

24. The method of claim 20 further including the step of introducing cementitious material into a bottom of a lower piling wrap from the lower piling wrap's inlet hole and then, once lower piling wrap has been filled with cementitious material, the upper piling wrap is filled using an inlet hole located at a bottom part of the upper piling wrap.

25. 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.

26. The support member reinforcement system wherein the support member is deteriorated.