GB2177148A

GB2177148A - Repairing concrete piles

Info

Publication number: GB2177148A
Application number: GB08516419A
Authority: GB
Inventors: Andrew Mcleish
Original assignee: Taylor Woodrow Construction Ltd
Current assignee: Taylor Woodrow Construction Ltd
Priority date: 1985-06-28
Filing date: 1985-06-28
Publication date: 1987-01-14
Also published as: GB8516419D0; AU5928586A; GB2177148B

Abstract

A method of repairing a concrete pile (1) comprises assembling a multi-part sleeve (3) around a damaged length of the pile, spaced from the pile so as to create a void (7) around the pile, and filling this void with grout. The grout-filled void is sealed from entry of air or water so that the repaired length of pile is protected from further damage. As shown in Fig. 2, the sleeve (3) may have spacers (6, Fig. 2) on the inner surface thereof. The sleeve can carry all the vertical and bending loads resisted by the original pile. <IMAGE>

Description

SPECIFICATION Repairing concrete piles This invention relates to repairing concrete piles.

Steel-reinforced concrete piles can suffer damage brought about by corrosion of the embedded steel reinforcement.

According to the present invention there is provided a method of repairing a concrete pile comprising assembling a sleeve around a damaged length of the pile, spaced from the pile so as to create a void around the damaged length of the pile, and filling the void with grout, the grout-filled void being sealed from entry of air or water. By "grout" is meant any suitable in-fill material such as a cementatious mortar or concrete mixture of pumpable quality.

The invention also provides a sleeve, for use in the method as just defined, comprising parts that can be assembled together around a damaged length of pile, these parts carrying spacers projecting inwardly from the inner circumferential surfaces of the parts for engaging the pile to space the circumferences of the parts from the pile.

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: Figure 1 is a perspective view of a repaired length of concrete pile, and Figure 2 is a cross-sectional view taken on line ll-ll in Figure 1 and to a larger scale.

The concrete pile 1 shown in the Figures is a steel reinforced pile having embedded reinforcing steel rods 2. As a result of corrosion of the rods 2, the pile 1 has suffered damage over a length less than the overall length of a steel sleeve 3 which is shown fitted around the pile 1.

In order to repair the pile, concrete is removed where it has cracked and loosened as a result of corrosion of the reinforcing rods 2, particularly at the corners as shown at A in Figure 2. The sleeve 3, which is in two semicircular section parts 3A and 3B, is clamped in position around the pile 1 by making-fast securing bolts 4 along opposed flanges 5A, 5B of the parts 3A and 3B. Internally the sleeve parts 3A, 3B carry spacers 6 that bear upon the pile 1 so that there is a void 7 between the inner circumferential surface of the sleeve 3 and the outer surface of the pile 1.

At the bottom of the assembled sleeve 3 the void 7 is closed at least to an extent to support grout that is to be pumped into the void 7. For example, a suitable stuffing material can be held in place by the action of clamping together the two sleeve parts. However, if the pile below the sleeve is in sufficiently good condition a neoprene seal ring is placed around the pile, held in place by a steel split collar that also serves to support the sleeve as the sleeve is placed in position.

Once the sleeve 3 is clamped to the pile 1 with the bottom of the void 7 closed and with sealing between the opposed flanges to prevent entry of air or water, and to prevent exit of grout, a suitable grout is pumped into the void 7 via an inlet 8 near the bottom of the sleeve. This grout is supplied to fill the void 7 and there thus become embedded therein shear-keys 9 that project inwardly from the inner circumferential surface of the sleeve.

At the top a polymer modified mortar 10 is applied to give a finished surface with a slope of about 1 in 3 downwardly away from the pile, this finishing surface serving to prevent entry of air or water into the grout filling the void 7. The bottom of the sleeve is also sealed in similar fashion if the closure previously placed does not give sufficient sealing against air or water. The sleeve itself may also be coated for corrosion protection.

It is to be noted that the length of the sleeve is such as to extend over a greater distance than the length of the damaged portion of the pile, and the sleeve remains in position at the completion of the repair. The amount of concrete that has to be removed at the commencement of the repair is limited to what is already loose, and no preparation of the reinforcement bars is required. The pile remains structural throughout the repair and after completion of the repair further corrosion of the reinforcement bars is minimised due to the water-oxygen starvation effect. If further corrosion does occur, its effects are withstood by the steel sleeve and do not result in spalling.

The sleeve can be designed to carry all vertical and bending loads resisted by the original pile.

1. A method of repairing a concrete pile comprising assembling a sleeve around a damaged length of the pile, spaced from the pile so as to create a void around the damaged length of the pile, and filling the void with grout, the grout-filled void being sealed from entry of air or water.

2. A method as claimed in claim 1, wherein the sleeve is assembled by clamping together parts of the sleeve at opposing flanges.

3. A method as claimed in claim 2 and comprising incoporating sealing material between the opposing flanges.

4. A method as claimed in claim 1, 2 or 3 and comprising incorporating sealing material at the bottom of the sleeve to retain the grout in the void.

5. A method as claimed in claim 1, 2 or 3, and comprising fitting a sealing ring around

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Repairing concrete piles This invention relates to repairing concrete piles. Steel-reinforced concrete piles can suffer damage brought about by corrosion of the embedded steel reinforcement. According to the present invention there is provided a method of repairing a concrete pile comprising assembling a sleeve around a damaged length of the pile, spaced from the pile so as to create a void around the damaged length of the pile, and filling the void with grout, the grout-filled void being sealed from entry of air or water. By "grout" is meant any suitable in-fill material such as a cementatious mortar or concrete mixture of pumpable quality. The invention also provides a sleeve, for use in the method as just defined, comprising parts that can be assembled together around a damaged length of pile, these parts carrying spacers projecting inwardly from the inner circumferential surfaces of the parts for engaging the pile to space the circumferences of the parts from the pile. 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: Figure 1 is a perspective view of a repaired length of concrete pile, and Figure 2 is a cross-sectional view taken on line ll-ll in Figure 1 and to a larger scale. The concrete pile 1 shown in the Figures is a steel reinforced pile having embedded reinforcing steel rods 2. As a result of corrosion of the rods 2, the pile 1 has suffered damage over a length less than the overall length of a steel sleeve 3 which is shown fitted around the pile 1. In order to repair the pile, concrete is removed where it has cracked and loosened as a result of corrosion of the reinforcing rods 2, particularly at the corners as shown at A in Figure 2. The sleeve 3, which is in two semicircular section parts 3A and 3B, is clamped in position around the pile 1 by making-fast securing bolts 4 along opposed flanges 5A, 5B of the parts 3A and 3B. Internally the sleeve parts 3A, 3B carry spacers 6 that bear upon the pile 1 so that there is a void 7 between the inner circumferential surface of the sleeve 3 and the outer surface of the pile 1. At the bottom of the assembled sleeve 3 the void 7 is closed at least to an extent to support grout that is to be pumped into the void 7. For example, a suitable stuffing material can be held in place by the action of clamping together the two sleeve parts. However, if the pile below the sleeve is in sufficiently good condition a neoprene seal ring is placed around the pile, held in place by a steel split collar that also serves to support the sleeve as the sleeve is placed in position. Once the sleeve 3 is clamped to the pile 1 with the bottom of the void 7 closed and with sealing between the opposed flanges to prevent entry of air or water, and to prevent exit of grout, a suitable grout is pumped into the void 7 via an inlet 8 near the bottom of the sleeve. This grout is supplied to fill the void 7 and there thus become embedded therein shear-keys 9 that project inwardly from the inner circumferential surface of the sleeve. At the top a polymer modified mortar 10 is applied to give a finished surface with a slope of about 1 in 3 downwardly away from the pile, this finishing surface serving to prevent entry of air or water into the grout filling the void 7. The bottom of the sleeve is also sealed in similar fashion if the closure previously placed does not give sufficient sealing against air or water. The sleeve itself may also be coated for corrosion protection. It is to be noted that the length of the sleeve is such as to extend over a greater distance than the length of the damaged portion of the pile, and the sleeve remains in position at the completion of the repair. The amount of concrete that has to be removed at the commencement of the repair is limited to what is already loose, and no preparation of the reinforcement bars is required. The pile remains structural throughout the repair and after completion of the repair further corrosion of the reinforcement bars is minimised due to the water-oxygen starvation effect. If further corrosion does occur, its effects are withstood by the steel sleeve and do not result in spalling. The sleeve can be designed to carry all vertical and bending loads resisted by the original pile. CLAIMS

5. A method as claimed in claim 1, 2 or 3, and comprising fitting a sealing ring around the pile to seal the bottom of the sleeve when the sleeve is assembled around the pile, this sealing ring being held in place by a split collar that also serves to support the sleeve as it is assembled.

6. A method as claimed in any one of the preceding claims and comprising applying a finishing surface to the grout-filled void at the top of the sleeve, this surface sloping downwardly away from the pile.

7. A method as claimed in any one of the preceding claims and comprising coating the grout-filled sleeve for corrosion protection.

8. A method of repairing a concrete pile substantially as hereinbefore described with reference to the accompanying drawing.

9. A sleeve for use in the method claimed in any one of the preceding claims, comprising parts that can be assembled together around a damaged length of pile, these parts carrying spacers projecting inwardly from the inner circumferential surfaces of the parts for engaging the pile to space the circumferences of the parts from the pile.