Introduction The present invention relates to a system for connecting prefabricated reinforcement cages of the type commonly used to strengthen concrete piles.

Background to the Invention Piling cages are used to reinforce cast in-situ concrete piles. Piles are created by boring a hole, inserting the piling cage and filling the hole with concrete. The finished pile is made from concrete but has steel reinforcement in the form of the piling cage.

Pile cages can be designed to be virtually any length, but are not normally longer than approximately 50 metres. Due to the practicalities of manufacture, handling and transportation, it is usually necessary to make the cages in sections not normally longer than a trailer length of approximately 12 metres.

The assembly of pile cages which are significantly longer than the pile cage sections requires the sections to be securely connected together to provide a reinforcement that is the same length as the pile which it is to reinforce.

It is known to splice the longitudinal reinforcement bars from one cage section to the next, using multiple 'bulldog clamps'. Whilst this is a technically effective method, it is time consuming and requires the operative(s) to spend long periods of time with their hands inside the pile cage whilst it is above ground to create multiple clamp connections before then lowering that section of cage into the ground. This constitutes a significant risk to the operative(s), as the potential exists for the upper cage to slip or move during the fitting of the bulldog clamps trapping, cutting or even severing the operative's hands. Furthermore because multiple clamp connections are made to the longitudinal reinforcing rods as each 'bulldog clamp' is placed in position it becomes more difficult for subsequent connections to be made, causing application of the final 'bulldog clamp' to be especially difficult. Circumferential steel bands are routinely welded to the longitudinal reinforcement rods where cage intersections occur to act as potential lifting points for crane hooks and to reduce the risk of bursting when the cages are filled with concrete.

GB0903345.7 Kierbeck Ltd describes a clamp for joining circumferential bands of adjacent cage sections together. The clamp has a pair of interconnecting claws located about a rod and one or more retaining means for tightening and loosening the clamp. The rod may be threaded at one or both ends and the claws may be separated and the clamp loosened by rotating the one or more threaded retaining means. The preferred type of retaining means is a tie-rod hexagonal nut but it could be a puddle weld. The preferred type of claw is the Lindapter® CF.

Summary of the Invention

It is an object of the present invention to provide an improved piling cage section which is easier to deploy. It is another object of the invention to provide an improved piling cage section which is cheaper to deploy. It is another object of the invention to provide an improved piling cage section which is safer to deploy.

In accordance with a first aspect of the invention there is provided a piling cage section comprising: a plurality of longitudinally extending bars which define the shape of the piling cage section;

one or more brace which retain the bars in position with respect to one another, the piling cage having a first end comprising a length of the longitudinally extending bars which has a first cross-sectional area;

a second end remote from the first end; and

a first connector member positioned at the first end on the outer perimeter of the cage wherein a second piling cage section which has a second cross-sectional area larger than the first cross-sectional area and has a second connector member positioned at an end thereof which is positioned on the inner perimeter of the cage and is mateable with the first end of the piling cage section;

and wherein a fixing is provided to connect together the piling cage section with the second piling cage section. Preferably, the second end has a second cross-sectional area larger than the first cross-sectional area and a second connector member positioned at an end thereof and being positioned on the inner perimeter of the cage is mateable with the first end of the piling cage section. Preferably, the fixing connects the first connector to the second connector.

Preferably, the cross-sectional shape of the piling cage is substantially circular.

Optionally, the cross-sectional shape of the piling cage is substantially square or rectangular.

Preferably, the one or more brace comprises wire loop attached to the outer surface of the longitudinally extending bars in a helical arrangement. Preferably, the first connector member is a bar or band which extends continuously around the perimeter or circumference of the cage to form a closed loop.

Preferably, the first and second connectors comprise a closed loop.

Preferably, the first connector member is substantially circular.

Optionally, the first connector member is substantially square or rectangular. Optionally, the first connector member is a plurality of discrete abutments spaced around the perimeter or circumference of the cage.

Preferably, the second connector member is a bar or band which extends continuously around the perimeter or circumference of the cage to form a closed loop.

Preferably, the second connector member is substantially circular

Optionally, the second connector member is substantially square or rectangular. Optionally, the first connector member is a plurality of discrete abutments spaced around the perimeter or circumference of the cage.

Optionally, the second connector member is a plurality of discrete abutments spaced around the perimeter or circumference of the cage.

Optionally, the one or more brace comprises wire connected to the outer surface of the longitudinally extending bars

Preferably, one or more positioning support is located below the connecting member. Preferably, one or more stiffener is located along the length of the piling cage section to increase its rigidity.

Preferably, one or more lifting band is provided along the length of the piling cage section for connection to a suitable lifting device to manoeuvre the piling cage section into position, in use.

Preferably, the fixing comprises a clamp which is connectable to the first connector member and the second connector member.

Preferably, the fixing comprises a clip and a wire, which is coupled to the first connector member and the first connector member and the second connector member and to the clip. Preferably, the wire is passed around the first connector member and the first connector member.

Preferably, there is further provided a brace for tensioning a first or second connector which is a closed loop connector as defined in the first aspect of the invention, the brace being provided to prevent deformation of the shape of the loop prior to deployment.

Preferably, the brace comprises a plurality of wires which are coupled to the connector member, each wire being coupled to opposing points on the loop. Preferably, the opposing points are diametrically opposite.

Preferably, the wires are tensioned and the tension is balanced between the wires to prevent deformation of the loop. Preferably, the wires are removeably coupled to the loop. Preferably, the wires are removeably coupled to the loop by means of a clip.

Preferably, the wire is a single length of wire which extends through the walls of the loop and is releasably secured in position by a clip.

In accordance with a second aspect of the invention there is provided a brace for tensioning a first or second connector which is a closed loop connector as defined in the first aspect of the invention, the brace being provided to prevent deformation of the shape of the loop prior to deployment.

Preferably, the brace comprises a plurality of wires which are coupled to the connector member, each wire being coupled to opposing points on the loop. Preferably, the opposing points are diametrically opposite.

Preferably, the wires are tensioned and the tension is balanced between the wires to prevent deformation of the loop. Preferably, the wires are removeably coupled to the loop.

Preferably, the wires are removeably coupled to the loop by means of a clip.

Preferably, the wire is a single length of wire which extends through the walls of the loop and is releasably secured in position by a clip.

In accordance with a third aspect of the invention there is provided a method of joining piling cage sections using the apparatus of the first aspect of the present invention. Brief Description of the Drawings

The present invention will now be described with reference to the accompanying drawings in which:

Figure 1a and 1b are side views of a first embodiment of the present invention which shows the first end and second end of the piling cage section separately;

Figure 2 is a side view of a first end of a piling cage section of figure 1 mated with a second piling cage section;

Figure 3 is a perspective view of a second embodiment of a second end of piling cage section in accordance with the present invention; Figure 4 is a perspective view of a second embodiment of a first end of piling cage section in accordance with the present invention;

Figure 5 is a perspective view which shows the first end and the second end of two separate piling cage sections in accordance with the present invention connected together;

Figure 6 is a perspective view of a clamp for use in one or more embodiment of the present invention; Figure 7a is a side view of the clamp of figure 6 as used to fix together connectors at the first and second ends of adjoining piling cage sections, figure 7b is a side view of the same;

Figure 8 is a perspective view of a clip which is used in a fixing for connecting together piling cage sections in accordance with the present invention; Figure 9 is a perspective view of a fixing which uses the clip of figure 8 for connecting together piling cage sections in accordance with the present invention; and Figure 10 is a side schematic view of a connector brace for maintaining the shape of connectors prior to or during their deployment.

Detailed Description of the Drawings The present invention provides a system for the fabrication and connection of cage segments, "over the hole" on site. It enables a piling contractor to receive long pile cages in sections that can be quickly and seamlessly connect together. The system is universally applicable and can cater for all types of multi bored section piles where the use of multi section cages is applicable.

The cages have first and second ends which have different cross-sectional areas as defined by the bars. In effect, this allows a first end of one piling cage section to be mateable with a second end of another piling cage section. Cages are designed to comprise "male" and "female" ends where the "male" end has a "joggled" section bent to have a smaller cage cross-sectional area. The bars of a specified lap length fit closely inside and parallel to the longitudinal bars of the "male" cage. Laps of any length or varying lengths may be specified and the laps can, if required, be of different diameters to the bars in the "female" cage. Changes in the numbers of longitudinal bars from one section to another can also be accommodated

The piling cages are generally but not exclusively constructed using mild steel flat bar bands or rings of reinforcing bar, within the cage structure. Figure 1 is a side view of a first embodiment of the present invention which shows the first end and second end of the piling cage section separately. It shows a piling cage section 1 which comprises a plurality of longitudinally extending bars 3. The relative position of the bars is maintaned by supports 5. In this example of the present invention, the piling cage section 1 has a substantially circular cross-section and supports 5form a circular helix which extends down the length of the piling cage section 1.

The first end 7 comprises a section where the bars 3 have been bent or joggled inwards 25 and thereafter a straight section of bars 27 extends to an open end which has a first cross-sectional area 11 and diameter 29. Connector member 15 extends around the outer circumference of the bars at a position immediately beyond the joggled section 25. In this example, the connector member 15 is a continuous metal band of suitable strength and size to be mateable with or abut against a corresponding band 17 on the second end of an adjoining piling cage section.

The second end 9 comprises a section where the bars 3 are straight and extend to an open end which has a second cross-sectional area 13 and diameter 31. Connector member 17 extends around the inner circumference of the bars at a position at the open end. In this example, the connector member 17 is a continuous metal band of suitable strength and size to be mateable with a corresponding band 15 on the first end of an adjoining piling cage section.

Positioning support 19 is located below the connecting member 17 and as is shown in figures 3 and 5 provides a stable base upon which the piling cage section 1 may rest whilst it is being fitted.

The support band 19 is generally located 250mm below the connector 17 at the top of the second end 9 to enable this section of the cage be suspended from the pile liner casing temporarily using a trapping device or support beam 33 whilst the first (male) end 7 is inserted and coupled. These bands are welded to the main longitudinal bars with an amount of weld adequate to support the weight of the cage suspended from that point and adequate to resist all temporary and installation loads imposed by the lifting and installation processes together with an appropriate factor of safety.

Stiffener bands 23 are located along the length of the length of the piling cage section to increase its rigidity.

The connecting members or splicing bands 15, 17 are selected to withstand bending, torsion and shear forces imposed by clamping devices 35 (figure 5), are located within the end sections 7, 9 such that when the cage sections are joined together, the bands meet edge to edge and the requisite lap length from the first (male) end 7 of longitudinal steel projects into the second (female) end 9. These bands 15, 17 are welded to the main longitudinal bars with an amount of weld adequate to support the weight of the cage suspended from that point and adequate to resist all temporary and installation loads imposed by the lifting and installation processes together with an appropriate factor of safety. The outside diameter and therefore cross-sectional area of the band fitted on the outside of the joggled section of the first (male) end of the cage is generally designed and built 10mm in diameter smaller than its counterpart band on the inside of the second (female) end of the cage to create a clearance for installation. Lifting bands 21 are shown which have loops to which a crane hook or other suitable lifting device may be attached for manoeuvring the piling cage section into position. The type of lifting band is dependent upon the handling and lifting methodologies which will be used and are subject to design calculations proving the structural stability of the cage in the temporary conditions to which it is subjected during fabrication,

transportation and installation. These bands are designed in conjunction with forming rings 22, to act as structural skeleton dictating the diameter and shape of the cage, to act as lifting positions for the handling of the cage in the horizontal orientation both in the works and on site, to act as lifting positions for the cage in lifting from the horizontal to the vertical orientation, to act as a lifting band for the cage and any further supported elements during installation and to act as a "Clamping Band" for connecting the cage sections together. The positioning of the bands is carefully calculated to take account of the constituents and geometry of the cage to ensure horizontal lifting.

Figure 2 shows a first end 7 of a piling cage section in accordance with the present invention connected to a second end 9 of a suitable piling cage section. It shows connector band 15 in abutment with connector band 17 just beyond joggled section 25. The straight section 27 of the first end 7 has a smaller cross-sectional area 11 and diameter 29 than the corresponding cross-sectional area 13 and diameter 31 of the second end 9. Consequently, the bars of the straight section are positioned in mateable relationship and are inserted in the second end 9.

Figure 3 is a perspective view of a second embodiment of a second end of piling cage section in accordance with the present invention. In this example, reference numerals from the first embodiment have been retained where identical or very similar features and components are described. In this diagram, the second end of a piling cage section 1 is deployed into a hole upon a poured concrete cylinder 32. The poured concrete cylinder provides a base upon which a positioning support can be rested with the aid of positioning support beams 33 which extend across the concrete cylinder 32 to support the piling cage section 1.

Figure 4 is a perspective view of a second embodiment of a first end of piling cage section in accordance with the present invention. In this example, reference numerals from the first embodiment have been retained where identical or very similar features and components are described. It will be appreciated that a piling cage section in accordance with the present invention may be configured to have two "first ends" 7 separated by lengths of bars with corresponding circumferential supports. In this case, they would be mateable at both ends with piling cage sections having appropriately configured "second ends" 9.

Figure 5 is a perspective view which shows the first end and the second end of two separate piling cage sections in accordance with the present invention connected together. In addition to the features of the connection shown in figure 2, a fixing, in the form of a clamp 35 is shown.

The clamp and its operation are shown in more detail in figures 6, 7 a and 7b. Figure 6 is a perspective view of the clamp 41 which comprises a top nut 43, an upper clamp jaw 47, a lower clamp jaw 49 a lower nut 51 and a locking nut 53 all mounted on a tie rod 45.

Figure 7a is a side view of the clamp of figure 6 as used to fix together connectors at the first and second ends of adjoining piling cage sections, figure 7b is a side view of the same. It shows the upper clamp jaw 47 coupled to the first connector member 15 and the lower jaw 49 coupled to the second connector member 17. The top nut 43 is fixed in position and the bottom nut is free to move up or down as needed until it is fixed in position by locking nut 53.

The clamp assembly has been tested in laboratory and simulated conditions to loads typically in excess of 80 kN and is thus capable of taking a service load of 30kN with a factor of safety of 2.5

Figures 8 and 9 show another embodiment of a fixing in accordance with the present invention. The clamp of figures 8 and 9 is of particular use in smaller/lightweight cages as a more suitable and cost effective alternative to clamp 41. Figure 8 is a perspective view of a clamp 61 which is used in a fixing for connecting together piling cage sections. It comprises a body 63 with a wire 67 which has a stopper or ferrule 65.

Figure 9 is a perspective view of a fixing which uses the clamp 61 of figure 8 for connecting together piling cage sections in accordance with the present invention. In this example, the clamp comprises a short length of 4mm high tensile wire rope 67 with a stop ferrule 65 on one end, passed through a specially modified KL200 Zip Clip device 63. The free end of the wire rope is passed around the connectors 15, 17, returning to the locking device where it is locked off and tightened to eliminate slack.

The clamp is deployed in the following manner. 1. take an individual ZIP SPLICE and hold the locking device against the edge of the top coupling band 15.

2. loop the free end of wire underneath the bottom coupling band 17.

3. Place the free end of wire through the available entry hole in the locking device to form a loop around both bands 15, 17.

4. pull wire 67 tight to eliminate any slack.

Multiple clamps 61 are used in order to effectively spread the weight load.

The clamp 61 has been tested to in laboratory and simulated conditions to loads typically in excess of 20Kn.

In heavy cages, there is a tendency for the bands, and as a consequence, the fabricated pile cage to become oval under its own weight in fabrication and handling, making it difficult to join cages together. Traditionally, these have been braced with struts of steel bar/band welded into the band. Increasingly, piling contractors need to be able to remove the bracing in the installation process as it becomes an impediment to follow on operations and the removal of traditional welded struts is problematic and potentially dangerous.

The solution described in figure 10 is a secured lightly tensioned and diametrically opposed wires, acting like bicycle wheel spokes to maintain the roundness of the cage until safely joined in the vertical plane. These wires can be easily removed with a handheld cutting device.

Figure 10 is a side schematic view of a connector brace for maintaining the shape of connectors prior to or during their deployment which uses a clip 61 and wire 67 which is threaded through holes drilled in the connector brace 72 and tightened evenly so as to retain the circular shape of the connector brace 72. Excess wire is pulled through the clip 77 and the tension may be released and wires removed once the connector brace is successfully deployed.

Improvements and modifications may be incorporated herein without deviating from the scope of the invention.