GB1590092A

GB1590092A - Method of lifting or reinforcing an existing structure

Info

Publication number: GB1590092A
Application number: GB4466177A
Authority: GB
Original assignee: Schroot C J
Current assignee: Schroot C J
Priority date: 1976-10-29
Filing date: 1977-10-27
Publication date: 1981-05-28
Also published as: NL7612009A; NL169507C; DE2746916A1; NL169507B; BE860212A

Description

(54) IMPROVEMENTS IN OR RELATING TO A METHOD OF LIFTING OR REINFORCING AN EXISTING STRUCTURE (71) I, CORNELIS JORINUS SCHROOT, a Dutch subject of the Queen of the Netherlands of Jacob Catslaan 3, Schiedam, the Netherlands, do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a method of stabilising a wall for the purpose of lifting or reinforcing an existing structure.

It is often the case that a valued structure e.g. a dwelling, a monument or even a single wall, has to be protected against subsidence or other structural failure and for this purpose is subjected to a renovation and/or a lifting operation. When forces have to be exerted on a structure for changing its position it has to be able to withstand these forces, and in the case of buildings it is necessary to repair, point or otherwise reinforce certain parts, especially walls, thereof.

The term "stabilisation" when used in this specification, will be understood to mean any operation for reinforcing a structure to withstand external forces, whether naturally occurring or applied deliberately. Stabilisation of a structure may be required even when a lifting operation is not necessary, and the cost of conventional repairs and renovation undertaken for the purpose of stabilisation is often extremely high.

The present invention seeks to provide apparatus and a method for stabilising a wall of a structure in a more economic and effective manner.

According to one aspect of the present invention there is provided a method of stabilising a wall for the purpose of jacking up or reinforcing an existing structure, in which abutment means are engaged with opposite end faces of a horizontallyextending, lower zone of the wall and are interconnected by connecting means which extend alongside said lower zone, which connecting means are tensioned to exert a longitudinally-acting compressive force on said zone.

As a result of this compressive force the lower, longitudinal zone of the wall acquires the properties of a prestressed beam and is thereby better adapted to resist bending moments, and in particular the bending moment applied as a result of the weight of the upper wall portions, particularly when the wall has become unstable through weathering. This method makes it possible to jack up a wall, which has been simply, inexpensively and effectively stabilised, by means of jacks, without the risk of cracks or collapse of either the wall of the structure of which it forms part (if this is also suitably reinforced). Even when the stabilisation is not performed for the purpose of lifting a structure but only for its own sake, the present invention, on account of its simplicity and inexpensiveness, is particularly suitable.

According to another aspect of the present invention there is provided apparatus for stabilising a wall for the purpose of jacking up or reinforcing an existing structure, including abutment means for engagement with opposite end faces of the wall, connecting means for extending along each side of the wall to interconnect the abutment means and means for tensioning the connecting means, in use, to exert a longitudinallyacting compressive force on the wall and further including supports which project longitudinally beyond the ends of the wall to receive forces for lifting the wall.

The invention will now be more particularly described, by way of example, with reference to the accompanying drawings, wherein: Fig. 1 is a horizontal cross-section of a part of the structure, on which are applied tensioning means for application of the method according to the invention; Fig. 2 is a vertical cross-section on the line II-II in Fig. 1; and Fig. 3 is a vertical cross-section on the line 111-111 in Fig. 1.

In Fig. 1 a wall of astructure is indicated by 1; perpendicularly abutting wall 1 are two transverse walls 2.

Along the wall 1 there are disposed on either side thereof, in opposite relationship, two horizontal, angle section beams 5 and 6, which are supported by means of a number of tie rods 7 with threaded ends extending through the wall 1 and the beams 5 and 6, and which are maintained under tension by nuts 7' so as to hold the beams 5 and 6 pressed against wall 1. The beams 5 and 6 extend beyond the ends of the wall 1, one beam, the beam 6, extending through an opening provided in walls 2 and 3. Two bearing plates 8 are attached, for example by welding, to the underside of the ends of beams 5 and 6 extending beyond the wall. A concrete block 9 is disposed on each plate 8, either by casting in situ, or in the form of a prefabricated block.Against each block 9 there is arranged a clamp plate 10 through which extend the ends of tensioning rods 11 and 12, which may be, for example, bars of high grade steel having rolled-on lugs in a helical pattern, which rods lie just above the lower flange of the beams 5 and 6, and extend therealong. The rods 11 and 12 have threaded ends and are kept under tension by means of nuts 13, so that they press the clamp plates 10 against the concrete blocks 9 to apply a compressive force to the region of the wall adjacent the beams 5 and 6. The effect of this is to cause this region of the wall to behave as a prestressed beam.

The tensioning of the rods 11, 12 can be effected simply by screwing up the nuts 13, but alternatively a conventional hydraulic actuator may be utilised; one end of such an actuator would press against a clamp plate 10, and the other end would be attached in some way, for example by additional nuts, to extensions of the ends of rods 11, 12. The nuts 13 would then only be screwed up to maintain the tension in the rods after this tension has been generated by the hydraulic actuator.

The length of the concrete blocks 9, that is their dimension parallel to the rods 11, 12, is such that between clamps 10 and the ends of beams 5, 6 there is provided a space sufficient to ensure that beams 5, 6 do not come under compressive load.

It will be clear that it is also possible to prestress a zone in walls 2 and 3 through compressive load in an identical manner.

The prestressed zones in walls 2 and 3 would lie at a slightly higher or lower level than the compression-stressed zone of wall 1, in order under that the beam ends and the concrete blocks can pass above or underneath each other as the case may be.

The beams 5 and 6, in the embodiment described, are not loaded in the longitudinal direction. In addition to supporting the concrete blocks 9, which might also be done in a different manner, they primarily serve for preventing the compression-stressed zone of the wall from deflecting laterally.

After tensioning the rods 11 and 12, these are preferably coated, together with the beams 5, 6 with an anti-corrosive coating indicated by the reference 14, to ensure protection against adverse weather influences.

A partly shown jack is indicated by the reference 15, by means of which, after stabilisation of the wall 1, this (and if necessary the walls 2 and 3) may be jacked up, if this is required. The jack 15 shown is a socalled Freyssinet jack.

In another embodiment of the invention (not shown) use is made of beams of appropriate form and strength in place of the beams 5, 6, which serve also as tensioning rods, so that the tensioning rods 11, 12 will not be required. At the ends of such beams there are mounted blocks or the like by means of a bolted or riveted connection or by welding, against which tie bolts extending through the clamp plates 10 can react in applying a compressive force to the wall. These beams, like the beams 5, 6, may be interconnected by tie rods 7 which press them against the wall 1.

WHAT I CLAIM IS: 1. A method of stabilising a wall for the purpose of jacking up or reinforcing an existing structure, in which abutment means are engaged with opposite end faces of a horizontally-extending, lower zone of the wall and are interconnected by connecting means which extend alongside said lower zone, which connecting means are tensioned to exert a longitudinally-acting compressive force on said zone.

2. A method as claimed in Claim 1, in which elongate reinforcing means are applied to opposite longitudinal faces of the lower wall zone so as to exert compressive forces on said zone transversely of the compressive forces exerted by the abutment means to resist buckling of the zone.

3. A method as claimed in Claim 2, in which the reinforcing means applied to opposite faces of the lower wall zone are interconnected by elements extending transversely through the wall.

4. A method as claimed in Claim 2 or Claim 3, in which the abutment means include concrete blocks engaged one with each end face of the wall zone and supported by respective ends of the reinforcing means.

5. A method as claimed in Claim 2, Claim 3 or Claim 4, in which each end of the reinforcing means projects beyond the adjacent end of the lower wall zone for receiving forces for lifting the said structure.

6. A method as claimed in any of Claims 3 to 5, in which the connecting means means which are tensioned comprise the reinforcing means.

7. A method of stabilising a wall for the purpose of jacking up or reinforcing an existing structure, substantially as herein described with reference to the accompany

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. which are supported by means of a number of tie rods 7 with threaded ends extending through the wall 1 and the beams 5 and 6, and which are maintained under tension by nuts 7' so as to hold the beams 5 and 6 pressed against wall 1. The beams 5 and 6 extend beyond the ends of the wall 1, one beam, the beam 6, extending through an opening provided in walls 2 and 3. Two bearing plates 8 are attached, for example by welding, to the underside of the ends of beams 5 and 6 extending beyond the wall. A concrete block 9 is disposed on each plate 8, either by casting in situ, or in the form of a prefabricated block.Against each block 9 there is arranged a clamp plate 10 through which extend the ends of tensioning rods 11 and 12, which may be, for example, bars of high grade steel having rolled-on lugs in a helical pattern, which rods lie just above the lower flange of the beams 5 and 6, and extend therealong. The rods 11 and 12 have threaded ends and are kept under tension by means of nuts 13, so that they press the clamp plates 10 against the concrete blocks 9 to apply a compressive force to the region of the wall adjacent the beams 5 and 6. The effect of this is to cause this region of the wall to behave as a prestressed beam. The tensioning of the rods 11, 12 can be effected simply by screwing up the nuts 13, but alternatively a conventional hydraulic actuator may be utilised; one end of such an actuator would press against a clamp plate 10, and the other end would be attached in some way, for example by additional nuts, to extensions of the ends of rods 11, 12. The nuts 13 would then only be screwed up to maintain the tension in the rods after this tension has been generated by the hydraulic actuator. The length of the concrete blocks 9, that is their dimension parallel to the rods 11, 12, is such that between clamps 10 and the ends of beams 5, 6 there is provided a space sufficient to ensure that beams 5, 6 do not come under compressive load. It will be clear that it is also possible to prestress a zone in walls 2 and 3 through compressive load in an identical manner. The prestressed zones in walls 2 and 3 would lie at a slightly higher or lower level than the compression-stressed zone of wall 1, in order under that the beam ends and the concrete blocks can pass above or underneath each other as the case may be. The beams 5 and 6, in the embodiment described, are not loaded in the longitudinal direction. In addition to supporting the concrete blocks 9, which might also be done in a different manner, they primarily serve for preventing the compression-stressed zone of the wall from deflecting laterally. After tensioning the rods 11 and 12, these are preferably coated, together with the beams 5, 6 with an anti-corrosive coating indicated by the reference 14, to ensure protection against adverse weather influences. A partly shown jack is indicated by the reference 15, by means of which, after stabilisation of the wall 1, this (and if necessary the walls 2 and 3) may be jacked up, if this is required. The jack 15 shown is a socalled Freyssinet jack. In another embodiment of the invention (not shown) use is made of beams of appropriate form and strength in place of the beams 5, 6, which serve also as tensioning rods, so that the tensioning rods 11, 12 will not be required. At the ends of such beams there are mounted blocks or the like by means of a bolted or riveted connection or by welding, against which tie bolts extending through the clamp plates 10 can react in applying a compressive force to the wall. These beams, like the beams 5, 6, may be interconnected by tie rods 7 which press them against the wall 1. WHAT I CLAIM IS:

1. A method of stabilising a wall for the purpose of jacking up or reinforcing an existing structure, in which abutment means are engaged with opposite end faces of a horizontally-extending, lower zone of the wall and are interconnected by connecting means which extend alongside said lower zone, which connecting means are tensioned to exert a longitudinally-acting compressive force on said zone.

ing drawings.

8. A structure when treated by the method according to any one of the preceding claims.

9. Apparatus for stabilising a wall for the purpose of jacking up or reinforcing an existing structure, including abutment means for engagement with opposite end faces of the wall, connecting means for extending along each side of the wall to interconnect the abutment means and means for tensioning the connecting means, in use, to exert a longitudinally-acting compressive force on the wall, and further including supports which project longitudinally beyond the ends of the wall to receive forces for lifting the wall.

10. Apparatus as claimed in Claim 9, including elements for interconnecting the connecting means through the wall, in use, and means for tensioning the said elements so that the connecting means exert transverse compressive forces on the wall at points spaced along the length thereof the supports being carried by projecting ends of the connecting means.

11. Apparatus as claimed in Claim 9, including separate reinforcing means for extending along each side of the wall, elements for interconnecting the reinforcing means through the wall, in use, means for tensioning the said elements so that the reinforcing means exert transverse compressive forces on the wall at points spaced along the length thereof, the supports comprising the projecting ends of the reinforcing means.

12. Apparatus for stabilising a wall, substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.