GB2235223A

GB2235223A - Reinforced concrete piles

Info

Publication number: GB2235223A
Application number: GB9014774A
Authority: GB
Inventors: Terence John Wilkinson
Original assignee: BACHY
Current assignee: BACHY
Priority date: 1989-07-10
Filing date: 1990-07-03
Publication date: 1991-02-27
Anticipated expiration: 2010-07-03
Also published as: GB8915723D0; GB2235223B; GB9014774D0

Abstract

A reinforcing cage 30 comprises a plurality of reinforcing bars located in substantially parallel spaced apart relationship to each other by a plurality of links 10. Each link comprises two spaced apart annular members 12, 14 interconnected by a plurality of elongate elements 16 to form a framework therewith. The reinforcing bars 32 pass over one annular member and through the other annular member of each link in contact with those members at respective locations spaced apart around the annular members. The cage is of particular use in forming cast-in-situ piles, the cage being inserted into the bore before pouring concrete, or inserted into the concrete after pouring. <IMAGE>

Description

REINFORCED CONCRETE PILES This invention relates to reinforced concrete piles, and more particularly, but not exclusively, to cast-in situ piles.

Such piles are formed by providing a bore hole and either pouring concrete into the bore hole over an elongate reinforcing cage already located in the bore hole or pouring the concrete into the bore hole and subsequently inserting an elongate reinforcing cage into the concrete in the bore hole.

Conventional elongate reinforcing cages comprise a plurality of reinforcing bars located in substantially parallel spaced apart relationship to each other by so-called 'links' spaced apart along the length of the cage, each link comprising an endless elongate member, formed for example in a square or a circle, to which the bars are tied. Such links provide only a limited degree of rigidity to the cage which can present problems during the formation of piles, particularly in the method in which the cage is inserted into concrete already in a bore hole.

One object of the present invention is to provide a link which provides reinforcing cages with more rigidity than the above described conventional links.

To this end, the invention includes a link for a reinforcing cage for a concrete pile, said link comprising two spaced apart annular members interconnected by a plurality of elongate elements to form a framework therewith such that substantially parallel reinforcing bars can pass over one annular member and through the other annular member in contact with the said members at respective locations spaced apart around said annular members.

The annular members may be substantially parallel to each other and in this case advantageously are substantially circular.

The elongate elements may be substantially parallel to each other and connected to the annular members at respective locations spaced apart therearound.

The elongate elements may extend beyond said other annular member away from said one annular member.

The invention also includes an elongate reinforcing cage for a concrete pile comprising a plurality of reinforcing bars located in substantially parallel spaced apart relationship to each other by a plurality of links as defined above spaced apart along the length of the case, each bar passing over said one annular member and through said other annular member of each link in contact with said members at respective locations spaced apart around the annular members..

Preferably each bar is tied to a respective elongate element of each link.

Preferably a link disposed adjacent one end of the cage has its said other annular member closer to that end of the cage, the relationship between the internal diameter of said other annular member, the external diameter of said one annular member and the diameter of the bars being such that the free ends of the bars extending beyond said other annular member are caused to flex inwardly towards the longitudinal axis of the cage.

Alternatively or additionally, the cage may be provided with a link, in which the elongate elements thereof extend beyond said other annular member away from said one annular member, disposed at one end of the cage with its said other annular member closer to that end of the cage, wherein the extensions of the elongate elements extend beyond the bars and are bent inwards towards the longitudinal axis of the cage.

The invention also includes a concrete pile having a reinforcing cage as defined above.

The invention also includes a method of forming a concrete pile, comprising providing a bore hole, at least partially filling the bore hole with concrete, thereafter inserting a reinforcing cage as defined above into the concrete in the bore hole, and allowing the concrete to cure.

The invention also includes a method of forming a concrete pile, comprising providing a bore hole, inserting a reinforcing cage as defined above into the bore hole, thereafter pouring concrete into said bore hole to cover the cage, and allowing the concrete to cure.

In order that the invention may be well understood, an embodiment thereof, which is given by way of example only, will now be described with reference to the accompanying drawing, in which: Figure 1 is a perspective view of a link for a reinforcing cage for a concrete pile; and Figure 2 is a perspective view of a reinforcing cage provided with two such links.

Referring to Figure 1, there is shown a link 10 which comprises two spaced apart annular members 12, 14 interconnected by a plurality of elongate elements 16 to form a framework therewith such that substantially parallel reinforcing bars can pass over annular member 12 and through annular member 14 in contact with those members at respective locations spaced apart around those members as will be described hereinafter in more detail in connection with Figure 2.

In the illustrated embodiment, the annular members are substantially parallel to each other and are substantially circular.

Further, the elongate elements are substantially parallel to each other and connected to the annular members at respective locations spaced apart therearound. Each annular member is formed from a steel bar which is formed into a circle and welded at its end portions with an overlap or a butt joint, and the elongate elements are also steel bars which are welded to the annular members. As illustrated, the elongate elements are welded to the exterior of the annular member 12 and the interior of the annular member 14. The resulting framework provides a rigid structure.

The elongate elements extend beyond at least the annular member 14 away from the annular member 12 and as shown also beyond the annular member 12 away from the annular member 14, these extensions being referenced 18 and 20 respectively in Figure 1.

Referring now to Figure 2, there is shown an elongate reinforcing cage 30 for a concrete pile which comprises a plurality of steel reinforcing bars 32 which are located in substantially parallel spaced apart relationship to each other by a plurality of links 10 spaced apart along the length of the cage. Each bar 32 passes over the annular member 12 and through the annular member 14 of each link in contact with those members.

The reinforcing bars 32 are tied to the links, for example to the elongate elements 16 thereof, by steel wire (not shown) in a conventional manner.

Although two links 10 are illustrated in Figure 30, the number of links used in any particular cage will depend on the overall length of the cage and the required rigidity thereof.

The maximum diameter of the cage 30 is the external diameter of the annular members 14 of the links. This diameter is selected to be less than the nominal diameter of the pile by an amount corresponding to the desired amount of concrete covering outside the annular members 14.

The external diameter of the annular member 12 is equal to the internal diameter of the annular member 14 less twice the diameter of a reinforcing bar 32 plus or minus a tolerance.

Advantageously, the relationship between the internal diameter of the annular member 14, the external diameter of the annular member 12 and the diameter of the reinforcing bars 32 is such that in a link at one end of the cage, the free ends of the bars 32 extending beyond the annular member 14 are caused to flex inwardly towards the longitudinal axis of the cage. This arrangement is particularly beneficial when the cage is used in a method of forming a concrete pile in which the cage is inserted into concrete in a bore hole, since if the free ends of the reinforcing bars 32 at the leading end of the cage flex inwardly towards the longitudinal axis of the cage there is less likelihood of these free ends breaking out of the concrete during insertion.

For the same reason, advantageously, the extensions 18 of the elongate element 16 of the links 10 are bent inwardly towards the longitudinal axis of the cage. This is particularly advantageous in the case of the link at the leading end of the cage when the extensions 18 extend beyond the bars 32.

As explained hereinbefore, the reinforcing cage illustrated in Figure 2 may be used in methods of forming concrete piles in situ wherein a bore hole is provided and the cage is inserted into the bore hole either prior to or after concrete has been poured into the bore hole. As will be appreciated from the above description the embodiment is particularly applicable to the method wherein the reinforcing cage is inserted into concrete already in the bore hole prior to the concrete being allowed to cure.

Claims

CLAIMS:

1. A link for a reinforcing cage for a concrete pile, said link comprising two spaced apart annular members interconnected by a plurality of elongate elements to form a framework therewith such that substantially parallel reinforcing bars can pass over one annular member and through the annular other member in contact with the said members at respective locations spaced apart around said annular members.

2. A link as claimed in claim 1, wherein said annular members are substantially parallel to each other.

3. A link as claimed in claim 2, wherein said annular members are substantially circular.

4. A link as claimed in claim 1, 2 or 3, wherein said elongate elements are substantially parallel to each other and connected to the annular members at respective locations spaced apart therearound.

5. A link as claimed in any one of the preceding claims, wherein said elongate elements extend beyond said other annular member away from said one annular member.

6. An elongate reinforcing cage for a concrete pile comprising a plurality of reinforcing bars located in substantially parallel spaced apart relationship to each other by a plurality of links as claimed in any one of the preceding claims spaced apart along the length of the cage, each bar passing over said one annular member and through said other annular member of each link in contact with said members at respective locations spaced apart around the annular members.

7. A reinforcing cage as claimed in claim 6, wherein each bar is tied to a respective elongate element of each link.

8. A reinforcing cage as claimed in claim 6 or 7, wherein a link disposed adjacent one end of the cage has its said other annular member closer to that end of the cage, the relationship between the internal diameter of said other member, the external diameter of said one annular member and the diameter of the bars being such that the free ends of the bars extending beyond said other annular member are caused to flex inwardly towards the longitudinal axis of the cage.

9. A reinforcing cage as claimed in claim 6, wherein a link as claimed in claim 5 is disposed at one end of the cage with its said other annular member closer to that end of the cage, wherein the extensions of said elongate elements extend beyond the bars and are bent inwardly towards the longitudinal axis of the cage.

10. A concrete pile having a reinforcing cage as claimed in any one of claims 6 to 9.

11. A method of forming a concrete pile, comprising providing a bore hole, at least partially filling the bore hole with concrete, thereafter inserting a reinforcing cage as claimed in any one of claims 6 to 9 into the concrete in the bore hole, and allowing the concrete to cure.

12. A method of forming a concrete pile comprising providing a bore hole, inserting a reinforcing cage as claimed in any one of claims 6 to 9 into the bore hole, thereafter pouring concrete into said bore hole to cover the cage, and allowing the concrete to cure.

13. A link or cage substantially as hereinbefore described with reference to the accompanying drawings.

14. A method of forming a concrete pile substantially as hereinbefore described.