AU2003262204C1

AU2003262204C1 - Improvements in the Manufacture of Pontoons and Piers

Info

Publication number: AU2003262204C1
Application number: AU2003262204A
Authority: AU
Inventors: William Dale Bourke
Original assignee: Pacific Pontoon & Pier Holdings Pty Ltd
Current assignee: Pacific Pontoon & Pier Holdings Pty Ltd
Priority date: 2003-11-13
Filing date: 2003-11-13
Publication date: 2011-08-04
Anticipated expiration: 2023-11-13
Also published as: WO2005047603A1; AU2006100205A5; AU2006100205B4; AU2003262204A1; AU2003262204B2

Abstract

Abstract A pontoon or pier contains a poured concrete deck which is surrounded by an aluminium frame. Threaded steel tie rods are embedded in the concrete and one end of the tie rods are attached to the aluminium frame. To prevent galvanic 5 corrosion caused by direct contact of the dissimilar metals of the steel tie rod and the aluminium frame, a plastic isolation sleeve is fitted between the tie rod and the aluminium frame. FIG I PRIOR ART

Description

1 IMPROVEMENTS IN THE MANUFACTURE OF PONTOONS AND PIERS Field of the Invention This invention is directed to an improvement in the manufacture of a pontoon/pier etc and is particularly directed to an improvement that reduces metal 5 corrosion. Background Art A pontoon or pier is a structure extending into the water and against which a boat can moor. Such structures are extremely well known and figure 1 illustrates a typical pontoon structure. 10 The pontoons are buoyant and typically have a deck made of poured concrete. The poured concrete sits within a perimeter frame which typically comprises a metal extrusion or section. Reinforcement mesh is placed within the perimeter frame prior to the concrete pour to provide strength. The perimeter frame needs to be securely anchored to the concrete such that it does not come loose. 15 However, just as importantly, the perimeter frame must not bow or deform under the weight of the poured concrete. It is typical for the perimeter frame to be made of extruded aluminium having a profile and a thickness which is such that the perimeter frame needs to be supported during the concrete pour to prevent deformation. For this reason, it is 20 known to provide tie rods one end of which is attached to the reinforcement mesh and the other end of which is attached to the inside wall of the perimeter frame. The tie rods prevent the perimeter frame from bowing under the weight of the concrete and also securely holds the frame in place. It is also advantageous to have some form of adjustability between the 25 tie rods and the perimeter frame. Thus, it is known for the tie rod to comprise a threaded bar. A nut is attached to one end of the threaded bar. The inside wall of the perimeter frame is provided with a channel which can accommodate the nut. The nut can then be tightened to tightly clamp the threaded bar to the perimeter frame. This arrangement is illustrated in figure 2. 30 Thereafter, concrete is poured to form the concrete deck of the pontoon or the pier. One disadvantage with the arrangement is that the perimeter frame can corrode. The corrosion is found to be caused by the dissimilar metals which usually is 2 the steel threaded bar and the aluminium surround frame. Corrosion occurs if water finds its way into the join between the threaded bar and the frame. Water can find its way into this area due to shrinkage and micro cracking of the concrete. The corrosion results in visual pitting of the aluminium surround frame and weakening of the frame. 5 Because of this corrosion, great care is presently taken to ensure that water does not leak or find its way into the area where the steel rod is clamped to the aluminium surround frame. Thus, flexible sealant etc are used. However, to date there has been no guarantee that any such sealant or coating can completely stop corrosion occurring. Thus, there would be an advantage if it were possible to reduce or eliminate this corrosion. 10 It will be clearly understood that, if prior art is referred to herein, this reference does not constitute an admission that the prior art forms part of the common general knowledge in the art in Australia or in any other country. Object of the Invention It is an object of the present invention to provide an arrangement that may at least 15 partially overcome the above-mentioned disadvantages or provide a useful or commercial choice. In one form, the invention resides in a pontoon or pier, said pontoon or pier comprising a concrete deck assembly, said deck assembly comprising a concrete deck and a metal frame surrounding said concrete deck, said concrete deck being formed of 20 concrete and reinforcing mesh embedded within said concrete, and at least one metal tie rod embedded in said concrete of the deck, said at least one tie rod being attached to said reinforcing mesh, said frame and rod being of dissimilar metals, said at least one tie rod attaching said reinforcing mesh to said metal frame, and an isolation member which prevents direct contact between the tie rod and the metal frame. 25 Typically, the metal frame is formed of metal frame members. The isolation member will typically sit between the metal frame member and the metal tie rod. The isolation member may be formed from any material that will prevent corrosion occurring. Typically, the isolation member will be formed of a plastic material and this may comprise a polyethylene, polyvinyl chloride, a nylon and the like, may 30 comprise a plastic composite material, may comprise another metal which can function as an isolation member- for instance lead, may comprise a woven structure, composite materials and the like. The metal frame defined by the metal frame members may be provided with an inwardly facing channel to facilitate attachment of the metal tie rod to the metal frame 3 member . The channel may comprise a slotted channel. The channel may extend entirely along the inside face of the metal members, or may comprise a number of discrete separate channels. The channel may be substantially U-shaped. The channel may have a width of between 1-10 centimetres, a height of between 0.5-5 centimetres. Of course, it 5 is envisaged that the tie rod can be attached to the frame member by other means and not necessarily requiring there to be a channel. The metal frame member typically comprises an extruded aluminium member which may have a complex profile. The aluminium member may have a wall thickness of between 1-5 millimetres. However, the metal frame member need not be limited to 10 aluminium and may be formed from other materials that may be susceptible to corrosion by contact with the tie rod. The tie rod typically comprises an elongate member. The length may be between 5-100 centimetres. The rod is typically solid and substantially circular and will typically have a diameter of between 5-30 millimetres. However, the rod need not be circular and 15 may comprise a rectangular cross-section, an oval cross section, an irregular cross section, or an angled member or a plate like member. The tie rod is typically manufactured from steel although no particular limitation is meant thereby, and the tie rod may be manufactured from other metals, metal composites and the like that may be susceptible to corrosion by contact with the metal frame. The rod may be solid or 20 hollow. The tie rod may be formed with or be provided with an attachment means to enable it to be attached to the metal frame. The attachment means may comprise an enlargement adjacent one end of the tie rod. The enlargement may comprise a nut. Therefore, the tie rod may have a threaded portion or may be entirely threaded to 25 accommodate the nut. However, other types of attachment means are envisaged including a hinged member on one end of the tie rod, a hook arrangement and the like. Suitably, the attachment means enables the tie rod to be attached to the metal frame and particularly to be attached to the metal frame by insertion of the attachment means into the channel on the metal frame. In a preferred embodiment, the attachment 30 means comprises a nut that can pass into the channel and held by the channel. Preferably the channel has a restricted entrance such that the nut can be captured in the channel. Preferably the restricted entrance into the channel is defined by a pair of inwardly directed opposing flanges. If the metal frame contains the inwardly facing channel, the isolation means 4 preferably comprises a sleeve which is complementary to, so as to fit within the channel and which will accommodate the attachment means of the tie rod. The sleeve may be formed from extruded plastic that can be fitted into the channel and slide therealong. . The sleeve may have a thickness of between 0.2-5 mm and preferably about 1-2 mm. In 5 a preferred from, the sleeve comprises a member of a generally U-shaped cross section. Part of the sleeve may extend through the restricted entrance of the channel. The sleeve may comprise a pair of outwardly extending flanges which overlie the flanges of the channel to prevent any part of the rod or nut from contacting any part of the frame. Alternatively, the isolation member may comprise a cover on the tie rod. The 10 cover may comprise a cap (for instance a plastic cap) which can be inserted into the channel whereby the tie rod is attached to the metal frame. The metal surrounding frame referred to above 1 includes the metal peripheral frame on a pontoon or pier, but no particular limitation is meant by the term surrounding frame. 15 Brief Description of the Drawings An embodiment of the invention will be described with reference to the following drawings in which: Figure 1. Illustrates a typical pontoon. Figure 2. Illustrates part of a pontoon just prior to the concrete pour which forms 20 the top deck. Figure 3. Illustrates in greater detail the attachment of a tie rod to portion of the surrounding frame via an isolation member. Figure 4. Illustrates an exploded view of portion of the surrounding frame, a tie rod, and isolation member. 25 Figure 5. Illustrates an exploded view of portion of the surrounding frame and the isolation member. Figure 6. Illustrates an assembled view of portion of the surrounding frame and the tie rod and the isolation member Best Mode 30 Referring to the illustrations and initially to figure 1, there is illustrated a typical pontoon design 10. The pontoon comprises a number of spaced apart decks 11. Each deck 11 contains a concrete walkway. Referring to figure 2, there is illustrated an aluminium surround frame 12 which is made of extruded aluminium. Reinforcement mesh 13 is laid within the perimeter of frame 12. Frame 12 is attached to reinforcement mesh 13 by a 5 number of spaced apart tie rods 14. The tie rods 14 are better illustrated in figure 3. In the particular embodiment, tie rods 14 are spaced apart typically by 1-2 metres. Each tie rod comprises a threaded circular steel rod having a length of between 30-40 centimetres and a diameter of about 10-15 millimetres. One end of each tie rod is welded to the 5 reinforcing mesh 13 (see figure 3). The other end of each tie rod 14 is attached to the aluminium surround frame 12 in a particular manner. Specifically, the aluminium surround frame 12 has a rather complex profile best illustrated in figures 4-6 but principally having an internal generally U-shaped channel 10 15 which is slotted and therefore has a smaller entry hole or slot 16 extending into a larger main body portion of the channel, the entry or slot 16 being defined between opposing inwardly directed flanges. Threaded rod 14 is provided with an attachment means which is in the form of a nut 17 15 which can be threaded to one end of rod 14. Nut 17 is sized to enable it to slide along the channel 15 but is prevented from extending from the entry hole 16, but nut 17 is captured within channel 15. To prevent direct metal to metal contact between the aluminium frame 12 and the steel rod 14 and steel nut 17, an isolation member in the form of a plastic sleeve 18 is provided. Sleeve 18 slides inside channel 15. Sleeve 18 has a design 20 such that part of the sleeve extends through hole 16 and contains a pair of outwardly extending flanges 19. The design of the sleeve and especially flanges 19 makes it virtually impossible for any part of the rod 14 or nut 17 to contact any part of the aluminium frame 12. 25 Prior to welding rod 14 to the reinforcement mesh 13, it is possible to rotate the rod to tightly clamp nut 17 in channel 15. The use of the plastic isolation member minimises any corrosion caused by direct contact of the similar metals. 30 Throughout the specification and the claims (if present), unless the context requires otherwise, the term "comprise", or variations such as "comprises" or "comprising", will be understood to apply the inclusion of the stated integer or group of integers but not the exclusion of any other integer or group of integers.

6 Throughout the specification and claims (if present), unless the context requires otherwise, the term "substantially" or "about" will be understood to not be limited to the value for the range qualified by the terms. 5 It should be appreciated that various other changes and modifications can be made to any embodiment described without departing from the spirit and scope of the invention. 10 15 20 25 30

Claims

1. A pontoon or pier, said pontoon or pier comprising a concrete deck assembly, said deck assembly comprising a concrete deck and metal frame surrounding said 5 concrete deck, said concrete deck being formed of concrete and reinforcing mesh embedded within said concrete, and at least one metal tie rod embedded within said concrete of the deck, said at least one tie rod being attached to said reinforcing mesh, the frame and rod being of dissimilar metals, said at least one tie rod attaching said reinforcing mesh to said metal frame, and an isolation member which prevents direct 10 contact between the tie rod and the metal frame.

2. The pontoon or pier as claimed in claim 1, wherein the frame has an inwardly facing channel wherein said at least one said tie rod is formed with or is provided with attachment means for attaching said at least one tie rod to said metal frame, said 15 attachment means being received in said channel .

3. The pontoon or pier as claimed in claim 2, wherein one end of the tie rod is threaded and wherein said attachment means comprises a nut which is threadably engaged with the at least one tie rod. 20

4. The pontoon or pier as claimed in claim 3 wherein said nut is captured in said channel.

5. The pontoon or pier as claimed in claim 4 wherein said channel is of a generally 25 U-shaped cross section and includes a pair of opposite return flanges defining a restricted entrance into the interior of said channel whereby said nut can be captured within said channel.

6. The pontoon or pier as claimed in claim 5 wherein the isolation member 30 comprises a plastic sleeve that fits within the channel.

7. The pontoon or pier as claimed in claim 6 wherein the plastic sleeve includes outer terminal flanges which extend through said restricted entrance out from the channel to prevent contact between said at least one tie rod and said channel. 8

8. The pontoon or pier as claimed in claim 2 wherein said attachment means comprises a cap or cover on said at least on tie rod, said cap or cover being adapted to be received within said channel to attach said at least one tie rod to said frame, said cap 5 or cover comprising said isolation member.

9. A pontoon or pier substantially as hereinbefore described with reference to Figures 3 to 6 of the accompanying drawings. 10