Classifications

• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
  • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
  • E02D5/22—Piles
  • E02D5/64—Repairing piles

Definitions

• This invention relates to the repair of structural members and relates particularly to improved methods and apparatus for effecting repairs of structures such as piles in situ.
• Piles such as those used to support jetties, wharves, piers, offshore structures such as steel jacket platforms and similar structures are subject to damage caused by erosion, corrosion and related chemical or electro-chemical erosion, and by impact such as from marine vessels and the like.
• a full sleeve may be formed by welding two half sleeves to the pile along longitudinal and end edges thereof thus effectively adding an outer skin to the damaged pile.
• the repair sleeve or part sleeve must extend substantially beyond the damaged area to provide the necessary strength to effect a proper repair, it is generally necessary to effect the welding of such sleeves in the tidal zone or underwater.
• Such welding is relatively expensive and time consuming, may require special equipment, and the welds so made, unless carried out with great skill, can be less than perfect, thus, compromising the structural integrity of the repaired pile.
• Australian Patent Specification No 59285/86 discloses a method of repairing a concrete pile by using a steel sleeve and filling the space between the sleeve with a grout.
• the method includes removing damaged concrete from the pile before placing the sleeve.
• the specification discloses the method in relation to a square pile and the sleeve is provided with internal, integral metal spacers formed as part of the sleeve and which bear on the surfaces of the pile.
• Such sleeves are relatively expensive and need to be custom made for each different type, shape and dimension of pile.
• United States Patent No 4,306,821 discloses a method for reconditioning structural piles whereby a building filler is placed into a space between a flexible sheet form and the damaged piling.
• the filler provides a protective and structural coating to the damaged piling.
• the strength of the repaired pile is dependent solely on the strength of the filler material, which is preferably an epoxy material and on the adhesive interface with the pile. Therefore, the amount of filler required is that amount necessary to provide the desired strength to the pile.
• United States Patent No 4,697,649 discloses a method of reinforcing a damaged post in the ground by providing a split casing having helical threads at one end which are driven into the ground by a casing rotary drive mechanism. An annulus between the casing and the post is filled with a suitable filler material.
• this system is designed for above ground posts and not for underwater piles. Further, the driving mechanism is relatively complex and expensive and adds substantially to the repair costs.
• US Patent No 4,439,070 relates to a method of restoring an underwater pile which uses a flexible jacket placed around the pile and filling the formed annular space between the pile and the jacket with an appropriate epoxy resin compound. Upper and lower seals are provided between the jacket and the pile and the jacket has inlet ports for injection of the epoxy resin and outlet ports for venting water from the annular space. Again, the strength of the repaired pile is dependent on the strength and amount of epoxy resin and on the adhesive interface with the pile, and the system relies on the effective operation of the seals at each end to form the closed annular space. A similar system is shown in Swiss Patent No 573520.
• a method of increasing the structural strength of a hollow, load bearing member such as a pile, including the steps of fitting a rigid, structural insert into the member, the insert having external dimensions less than the internal dimensions of the hollow member to provide an interspace between the member and the insert, supporting the insert so that it is spaced from the member, and filling the interspace between the insert and the member with an expansive filler, and allowing the filler to set, cure and thereby expand in such a way as to generate tensile forces on the member and compressive forces on the insert.
• the insert may be a single piece insert for those applications where a single piece insert is able to be engaged within the member. Otherwise, the insert may be formed of two or more parts which are interconnected, as by welding, bolts or other mechanical connectors, by clipping, by adhesion or chemical bonding, by the use of hinge means or by a combination of these.
• the insert is preferably spaced from the member by the use of spacer means, which may include spacing tabs, indentations or other deformations of the insert material or separate spacers including spacers formed of synthetic plastic or rubber materials or the like attached to the outer surfaces of the insert.
• spacer means may include spacing tabs, indentations or other deformations of the insert material or separate spacers including spacers formed of synthetic plastic or rubber materials or the like attached to the outer surfaces of the insert.
• spacer means may be attached to the member prior to engagement of the insert thereon or spacer means may be inserted between the member and the insert after the engagement of the insert within the member.
• a seal is provided between the lower edge of the insert and the member to seal the interspace between the insert and the member at the lower end thereof.
• a second seal may also be provided spaced from the first seal, and preferably at the upper edge of the insert. The seal or seals act to retain the expansive filler within the space between the insert and the member before the filler has set and expanded.
• seals may also be used between the parts of the insert, depending on the means of fixing the insert parts together.
• the expansive filler may comprise a grout, such as a cementitious grout to which an expansive agent is added so that the grout sets and expands on curing.
• the expansive filler when cured, induces tensile hoop stresses in the member and compressive hoop stresses in the insert so that loading actions on the member are able to be transferred between the member and the insert.
• the expansive filler may be a calcium-sulpho-aluminate or lime based mixture.
• the invention also includes the apparatus for repairing a damaged pile or otherwise increasing the strength of a load bearing member comprising an insert adapted to engage within the member, means to space the insert from the member, and an expansive filler adapted to fill the space and to expand on setting and curing to post-tension the insert, the filler forming a rigid interface between the insert and the member.
• shear keys are provided to positively and rigidly connect the insert with the expansive filler and to connect the filler with the member.
• the shear keys may comprise studs, bolts, including coach bolts or the like fastened to the member.
• the insert itself may also have outwardly extending shear keys formed by any suitable means including bolts, punched or pressed deformations of the insert, welded pins or the like.
• the shear keys may be preformed so as to also constitute the or some of the spacer means.
• a method of repairing a substantially tubular, cylindrical structural member, such as a pile, having a damaged area including the steps of securing insert means within the member, the insert means having an axial length to extend in both directions beyond the area of damage on the member and have an outer diameter smaller than the inner diameter of the member, spacer means to space the insert means from the member to form a substantially annular space therebetween, filling the annular space with an expansive grout, allowing the grout to set and expand within the space to thereby tension the member and apply compressive forces to the insert whereby the set grout facilitates load transfer between the member and the insert primarily by friction across the member/grout/insert interfaces.
• Fig. 1 is a part sectional view of a jetty pile and an encasing repair insert in accordance with the present invention
• Fig. 2 is a cross-sectional plan view of a cylindrical, tubular pile and an insert in accordance with one embodiment of the invention
• Figs. 1 and 2 are designed particularly for the repair of a cylindrical, tubular pile 12 such as those used for jetties and the like.
• Fig. 1 illustrates a jetty superstructure 14 supported by a pile 12 in a sea water environment.
• the sea water 15 has, over a period of time, caused corrosive damage 16 to the pile 12 over an area on the pile 12 generally corresponding to the tidal limits.
• the repair is effected by locating the insert 17 in the pile 12 and spacing the insert 17 from the pile to form a substantially annular space 18.
• the space 18 is then filled with an expansive grout 19 which expands when it sets thereby compressing the insert 17 and tensioning the pile thereby to form a substantially firm or rigid interface between the pile 12 and the insert 17.
• a seal 21 is provided at least around the lower edge of the insert 17 to extend between the insert 17 and the pile 12.
• the seal shown in Fig. 1 is formed by a flexible, deformable rubber ring engaged on the end of the insert 17.
• the seal 21 may be formed by any suitable means or material, including synthetic plastic material, mastic or the like.
• a second seal 22 is provided at the upper end of the annular space 18 to maintain the grout within that annular space during the initial setting and expanding period.
• a seal 22 is fitted in place after the grout has been conveyed into the annular space 18 and all water and air expelled, otherwise, provision needs to be made to allow the water and air to escape.
• the insert 17, which may be formed of two or more parts, is, when assembled, a load bearing member which is able to carry at least part of the load on the pile.
• the expansive grout must also be of a material which, on setting, facilitates load transfer between the pile and the insert.
• the preferred grout for use in this invention is a cementitious grout mixture having as an expansive agent a calcium- sulpho-aluminate formulation. Such a formulation has an initial setting period during which the grout hardens. This period is followed by a curing period during which the grout expands and generates radial pre-stress forces resulting in compressive hoop stresses in the insert 17 and tensile hoop stresses in the pile 12. A pre-stress of 12 MPa or more is achievable.
• the outer surface of the insert 17 by roughening the outer surface of the insert 17, a greater degree of resistance to slip between the grout and the insert is achieved.
• the surface roughness may be increased by any suitable means including machining, stamping, shot blasting or the like.
• the proportion of the additive in the grout mix is a key design variable in order to achieve a specific pre-stress through expansion in curing of the grout.
• an insert 17 is illustrated assembled within the pile 12 and is spaced therefrom by a series of internal deformable rubber spacers 27 which are fixed to the outside surface of the insert such as by adhesive or mechanical fastening.
• the spacers 27 are provided at several locations along the length of the inserts whereby, when the insert is located as illustrated, the spacers act to centre the insert 17 on the pile 12 so that a substantially annular space 18 exists between the insert 17 and the pile 12.
• This space is then filled with the expansive grout mixture aforesaid which, on setting, expands and produces compressive stresses in the insert 17 and tensile stresses in the pile 12, the grout being of a material which facilitates load transfer between the pile and the insert.
• An alternate form of spacer may comprise a ring formed of a flexible material, such as a spring steel or the like, and which is able to be clipped around the insert 17.
• the ring has a number of depending, outwardly extending legs the edges of which are adapted to engage the surface of the pile so that the body of the ring is spaced therefrom.
• the ring engages over the lower end of the insert 17 thereby supporting that end such that the insert 17 is evenly spaced from the pile.
• the lower seal may also be formed of one or more pockets of a flexible material, such as rubber, synthetic plastic material, fabric or the like, which are open at their upper end and are secured to the lower edge portion of the insert 17 by bonding or by any other suitable fastening means.
• the grout fills the pockets causing the face thereof to engage and seal against the surface of the pile.
• the grouted pockets thus form a seal preventing the expansive grout 19 passing downwardly and out of the annular space 18.
• the insert may be of solid construction or tubular as illustrated, and may be formed of metal, timber or the like.

Landscapes

• Engineering & Computer Science (AREA)
• Structural Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Mining & Mineral Resources (AREA)
• Paleontology (AREA)
• Civil Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Revetment (AREA)
• Piles And Underground Anchors (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=3813023

Family Applications (1)

Country Status (7)

Families Citing this family (3)

Citations (2)

Family Cites Families (3)

• 1999
  • 1999-02-22 AU AUPP8821A patent/AUPP882199A0/en not_active Abandoned
• 2000
  • 2000-02-21 EP EP00906057A patent/EP1155196A4/de not_active Withdrawn
  • 2000-02-21 CA CA002362143A patent/CA2362143A1/en not_active Abandoned
  • 2000-02-21 KR KR1020017010694A patent/KR20010112281A/ko not_active Application Discontinuation
  • 2000-02-21 JP JP2000601251A patent/JP2002538335A/ja active Pending
  • 2000-02-21 NZ NZ513618A patent/NZ513618A/en unknown
  • 2000-02-21 WO PCT/AU2000/000120 patent/WO2000050697A1/en not_active Application Discontinuation

Patent Citations (2)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events