GB2162567A - A pile construction - Google Patents

Abstract

A pile (1) is cast in situ in a borehole (3, 4) in the ground (2) in such a manner that the lower portion of the pile is of about two-thirds of the cross- sectional area of the upper portion thereof. More than one step can be provided in the pile and the step may be sharply defined as shown or tapered downwardly. <IMAGE>

Description

SPECIFICATION A pile construction This invention relates to a pile construction and to a method of making same.

In many tropical areas and in South-East Asia in particular, the strength of the ground increases with the depth of the ground from its surface.

Up till now, piles that have been cast in situ in such ground have been of substantially constant cross-section.

According to one aspect of the present invention, there is provided a pile that has been cast in situ and has its external peripheral surface of stepped configuration such that its cross-section in an upper horizontal plane is greater than its cross-section in a lower horizontal plane.

According to another aspect of the present invention, there is provided a method of making a pile cast in situ, the method including the steps of forming a hole in the ground in such a manner that its internal peripheral surface is of stepped configuration such that a part of it further from ground level is of smaller cross-sectional area than a part of it nearer to ground level, and pouring material to form the pile into the hole so formed and causing or allowing the material to set.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawing, in which the single Figure is a diagrammatic cross-sectional view of a pile.

The drawing shows a pile 1 that has been cast in situ in a borehole in the ground 2. Such a pile can have been made by initially boring the hole in such a way that a part 3 of it further from ground level is of smaller cross-sectional area than a part 4 of it nearer to ground level, then inserting a reinforcement cage (not shown) in the borehole and then pouring concrete into the borehole, thereby to form the cast pile. The reinforcement cage can either be such as to rest on the bottom of the borehole or as to be suspended in the borehole.

The pile so cast is therefore of stepped configuration, the upper portion of the pile being of greater cross-sectional area than is the lower portion of the pile. Preferably, the lower portion has a cross sectional area that is two thirds of the cross sectional area of the upper portion of the pile.

As shown, the step is sharply defined but it is also possible for the step to be in the form of a downward taper between the upper portion and the lower portion. Moreover, more than one step can be provided in the pile if required.

As compared with a conventional pile that has to carry the same load as that described with reference to the drawing, it has been found that a saving of about 15% in material can be made, even though the present pile should preferably extend more deeply into the ground than the conventional pile.

With such deeper extent into the ground, and with the ground conditions discussed above, the pile 1 is caused to terminate in firmer ground and thus gives a better performance, particularly a smaller settlement when under load, as compared with the conventional pile.

1. A pile that has been cast in situ and has its external peripheral surface of stepped configuration such that its cross-section in an upper horizontal plane is greater than its cross-section in a lower horizontal plane.

2. A pile as claimed in Claim 1, wherein the area of said cross-section in said lower horizontal plane is substantially two-thirds that of said cross-section in said upper horizontal plane.

3. A method of making a pile cast in situ, the method including the steps of forming a hole in the ground in such a manner that its internal peripheral surface is of stepped configuration such that a part of it further from ground level is of smaller crosssectional area than a part of it nearer two ground level, and pouring material to form the pile into the hole so formed and causing or allowing the material to set.

4. A method as claimed in Claim 3, wherein the cross-sectional area of said part further from ground level is substantially two-thirds that of said part near to ground level.

5. A pile as claimed in Claim 1 or 2, or a method as claimed in Claim 3 or 4, wherein the stepping in said stepped configuration is sharply defined.

6. A pile as claimed in Claim 1 or 2, or a method as claimed in Claim 3 or 4, wherein the stepping in said stepped configuration tapers downwardly.

7. A pile or a method as claimed in any preceding claim, wherein there is only one step in said stepped configuration.

8. A pile, substantially as hereinbefore described with reference to the accompanying drawing.

9. A method of making a pile, substantially as hereinbefore described with reference to the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION A pile construction This invention relates to a pile construction and to a method of making same. In many tropical areas and in South-East Asia in particular, the strength of the ground increases with the depth of the ground from its surface. Up till now, piles that have been cast in situ in such ground have been of substantially constant cross-section. According to one aspect of the present invention, there is provided a pile that has been cast in situ and has its external peripheral surface of stepped configuration such that its cross-section in an upper horizontal plane is greater than its cross-section in a lower horizontal plane. According to another aspect of the present invention, there is provided a method of making a pile cast in situ, the method including the steps of forming a hole in the ground in such a manner that its internal peripheral surface is of stepped configuration such that a part of it further from ground level is of smaller cross-sectional area than a part of it nearer to ground level, and pouring material to form the pile into the hole so formed and causing or allowing the material to set. For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawing, in which the single Figure is a diagrammatic cross-sectional view of a pile. The drawing shows a pile 1 that has been cast in situ in a borehole in the ground 2. Such a pile can have been made by initially boring the hole in such a way that a part 3 of it further from ground level is of smaller cross-sectional area than a part 4 of it nearer to ground level, then inserting a reinforcement cage (not shown) in the borehole and then pouring concrete into the borehole, thereby to form the cast pile. The reinforcement cage can either be such as to rest on the bottom of the borehole or as to be suspended in the borehole. The pile so cast is therefore of stepped configuration, the upper portion of the pile being of greater cross-sectional area than is the lower portion of the pile. Preferably, the lower portion has a cross sectional area that is two thirds of the cross sectional area of the upper portion of the pile. As shown, the step is sharply defined but it is also possible for the step to be in the form of a downward taper between the upper portion and the lower portion. Moreover, more than one step can be provided in the pile if required. As compared with a conventional pile that has to carry the same load as that described with reference to the drawing, it has been found that a saving of about 15% in material can be made, even though the present pile should preferably extend more deeply into the ground than the conventional pile. With such deeper extent into the ground, and with the ground conditions discussed above, the pile 1 is caused to terminate in firmer ground and thus gives a better performance, particularly a smaller settlement when under load, as compared with the conventional pile. CLAIMS

1. A pile that has been cast in situ and has its external peripheral surface of stepped configuration such that its cross-section in an upper horizontal plane is greater than its cross-section in a lower horizontal plane.

2. A pile as claimed in Claim 1, wherein the area of said cross-section in said lower horizontal plane is substantially two-thirds that of said cross-section in said upper horizontal plane.

3. A method of making a pile cast in situ, the method including the steps of forming a hole in the ground in such a manner that its internal peripheral surface is of stepped configuration such that a part of it further from ground level is of smaller crosssectional area than a part of it nearer two ground level, and pouring material to form the pile into the hole so formed and causing or allowing the material to set.

4. A method as claimed in Claim 3, wherein the cross-sectional area of said part further from ground level is substantially two-thirds that of said part near to ground level.

5. A pile as claimed in Claim 1 or 2, or a method as claimed in Claim 3 or 4, wherein the stepping in said stepped configuration is sharply defined.

6. A pile as claimed in Claim 1 or 2, or a method as claimed in Claim 3 or 4, wherein the stepping in said stepped configuration tapers downwardly.

7. A pile or a method as claimed in any preceding claim, wherein there is only one step in said stepped configuration.

8. A pile, substantially as hereinbefore described with reference to the accompanying drawing.

9. A method of making a pile, substantially as hereinbefore described with reference to the accompanying drawing.