FR2639380A1 - PROCESS FOR THE CONSTRUCTION IN LOW WATER OF A FOUNDATION BEAM OF A PERRE COVERING A WORK SUCH AS A BANK, A JET OR OTHER AND FOUNDATION BEAM THUS OBTAINED - Google Patents

Abstract

The method consists in hanging flexible envelopes 20 aligned and contiguous under a lifting beam, in lowering the lifting beam until it rests on supports with its envelopes touching the bottom 23 of a trench, in pouring concrete into the envelopes. by successive layers 31.1 to 31.4 and alternately in one direction (arrow F) and in the opposite direction (arrow G), to close the envelopes and unhook them, to move the lifting beam to the next location.

Description

Method for the construction in low water of a foundation beam of a

  riprap covering a structure such as a bank, a

  pier or other and foundation beam thus obtained.

  The present invention relates to a process for the construction or repair in low water of a foundation beam of a riprap covering a structure such as a bank, a

pier or whatever.

  Up to now, the foundation has been made up of hard rock blocks placed side by side and linked together. The weight of these blocks and their connection are essential

  to maintain the structure.

  The structure thus formed generally withstands the stresses to which it is subjected by moving water: current, waves, whirlpools, tide ...

  sea water or water from rivers sensitive to the tide.

  However, its repair or its construction step by step raises major difficulties. First of all, a competent workforce is no longer in sufficient quantity, the working conditions are painful and tiring, the cost of repairing is too expensive. Then and above all, it is only possible to work economically when the water is uncovered, that is to say three to four hours per tide and never at the same time, which implies a practically permanent availability of

Workforce.

  The present invention aims to remedy these drawbacks by proposing the use of concrete, so that the concrete poured parts and not yet consolidated constituting the foundation beam are not deteriorated when the sea or the river water rises 'and covers them. In addition, it must be possible

  to arm the beam in order to improve the overall resistance.

  Of course, the execution of this beam must be quick, efficient and inexpensive. It must be able to be interrupted without damage when the water rises. It should only require a reduced number of staff. The beam thus obtained in concrete

  must finally be solid, resistant and reliable.

  For this purpose and in accordance with the invnetion, the low beam construction process for the foundation beam consists of: - digging a trench, - hanging under a lifting beam suspended from a

  lifting a plurality of flexible envelopes having a parallel shape

  lepipedic and arranged side by side in at least one row at a spacing such that when they are filled, their adjoining transverse walls are strongly pressed against each other, - lower the lifter until it rests on means support, such as easels, so that the row of envelopes is housed in the trench by touching the bottom of the latter when filling begins, - to introduce longitudinal reinforcements crossing the transverse walls of all envelopes of the row and letting them protrude at least from the last to ensure the connection with the next row, - pour concrete into the envelopes, in particular by means of a pump, to deposit a first layer in a direction of one f-.loppe to the next in order to inflate the trans walls,:; ::: ies in this direction, then a second layer in the opposite direction in order to inflate the other transverse walls and so on te from level to level until filling is completed, - close the envelopes at their upper part and unhook them from the lifter, - move this lifter longitudinally to put in place another row of aligned envelopes with that considered, the first envelope of this other row being pierced to receive the protruding ends of the reinforcements of the

row already poured.

  According to a particular embodiment, the method consists in rolling a skirt of each envelope located above the handles attached to the lifting beam, in order to allow the pouring of the concrete, and after filling, to crease and tighten the skirt on itself to form a twist and tie that twist to

close the corresponding envelope.

  Advantageously, on the side of the slope of the riprap, transverse reinforcing elements are inserted in the envelopes filled before setting of the concrete, these reinforcing elements being intended to allow the connection of the beam with the layer of

protection of said riparian.

  The invention also extends to the beam of

  foundation obtained by implementing the above process.

  The beam is then formed by a plurality of aligned sections of concrete filling flexible envelopes closed and separated from each other by the compressed walls of these envelopes, each section having, at the same level on one side, projecting transverse parts. fitting into hollow transverse parts of the contiguous section and, on the other side, hollow transverse parts, the projecting parts being separated on the same side, from one level to the next,

by hollow parts.

  All sections of wrapped concrete are crossed by common longitudinal reinforcement with at least one end

protrudes.

  Reinforcement elements can be inserted in the sections of wrapped concrete in order to project according to the slope of the riprap for the connection of the foundation beam with the

pierced.

  Various other features and benefits of

  the invention will moreover emerge from the detailed description which

  follows. One embodiment of the subject of the invention is

  shown, by way of nonlimiting example, in the accompanying drawing.

  In this drawing: - Figure 1 is a cross section of a structure to which the foundation beam of the invention is applied, - Figure 2 is a perspective showing a flexible envelope used to form the beam, - Figure 3 is a vertical section taken along line III-III of Figure 2, when the envelope skirt is rolled. - Figure 4 is a partial longitudinal section of the finished beam, - Figure 5 is a perspective view with cutaway

  illustrating a first phase of the process.

  - Figures 6 to 9 are sectional elevations concerning the following phases of the process, - Figure 10 is a cross section taken along

line X-X in Figure 9.

  In the example shown, the structure to which the method of the invention applies is a pier 1 on which is built a roadway 2 bordered at least on one side by a sidewalk 3 and a concrete parapet 4. The pier is constituted in the form of an embankment with the natural terrain 5 which is covered by a riprap 6. The sloping surface 7 of the riprap which connects the circulation surface of the roadway 2 to the bottom 8 of the river or the sea,

  is coated with a riprap 9, the foot of which abuts against a foundation 10.

  The base of the pier 9, the foundation 10 and the neighboring part of the bottom 8 are covered by a reinforcing embankment It intended to protect this zone from the devastating action of the sea or the river. The water level on the river rises and falls with the tides and this movement of ebb and flow, is added that of waves, eddies, currents ... At low tide, the river 9 and foundation 10 are discovered and we only have

  three to four hours to work "dry".

  As shown in Figure 5, to reconstruct the foundation 10, a trench It is dug at the foot of the slope and a lifter 12 extending in line with the trench, is suspended from a lifting device 13. The lifter is made up by two beams 14 connected by crosspieces 15 and delimiting between them windows 16 through which the pipe 17 of a concrete pump 18 can pour concrete as it is indicated in

what follows.

263938O

  As is now apparent from FIG. 6, hooks 19 are fixed to the outside of the side members 14 of the lifter 12 opposite the crosspieces 15. Flexible envelopes 20 are attached to the lifter and their dimensions are such, relative to OS relative to - the spacing of the hooks 19, that they retain, in pendant, their parallelepiped shape and that they touch by their transverse walls; however, due to their flexibility, they can deform and the deformation of each of the transverse walls is transmitted without breaking contact with the

adjoining transverse wall.

  Easels 21 (FIGS. 5 and 7) are installed on the ground to receive the lifter 12 when it is lowered to its lower level. In this position, the bottoms 22 of the envelopes rest on the bottom 23 of the trench II and said transverse walls of these envelopes remain in contact. It is important that the envelopes remain suspended from the lifting beam, but they can take a slight "slack" to be sure that their bottoms rest on that of the trench, their transverse walls being

  still in contact despite this slight slack.

  These envelopes 20 can be of the type shown in Figures 2 to 4. They can be made of woven polypropylene fabric. They have a parallelepiped shape and have two transverse walls 24, 25 and two longitudinal walls 26, 27 connected together and with the bottom 23. In the upper corners, straps are formed in a U shape and fixed by their branches on the two adjoining walls. in order to constitute suspension handles 28 intended to be threaded on the hooks 19. Said walls 24 to 27 of the envelopes are extended, by a skirt 29 capable of being pleated and tightened on itself, the twist thus formed being capable of 'be

  knotted in 30 to close the corresponding envelope.

  As shown in Figures 3 and 7, the envelopes 20 of this type or another being suspended from the lifter 12 which rests on the trestles 21, the skirts 29 are rolled on themselves to form a roller 31 completely releasing the mouth 263938v of said envelopes; you can also fold the transverse walls 24, 25 and fold them down and out

longitudinal walls 26, 27.

  As indicated in the foregoing and as can be seen from FIGS. 4 and 8, concrete is poured into the casings 20 by means of the concrete pump 18. However, this pouring takes place in successive layers, sometimes in one direction ( arrow F),

  sometimes in the opposite direction (arrow G).

  More specifically, if we consider Figure 8, the envelopes being designated by the references 20.1 to 20.n from left to right, a first layer of concrete 32.1 is poured in the direction of arrow F of the envelope 20.1 up to envelope 20.n; the wall 25 of the casing 20. i during casting then deforms towards the outside and pushes back the wall 24 of the following casing 20.i + 1; it follows that in each envelope, the layer 32.1 of concrete has a projecting transverse part 33 on the right and a hollow transverse part 34 on the left, the projecting parts fitting into the hollow parts. A second layer of concrete 32.2 is poured in the direction of arrow G from the envelope 20.n to the envelope 20.i; it is now, the wall 24 of each envelope 20.i during casting which deforms towards the outside and pushes back the wall 25 of the following envelope 20.i-1; as a result, in each envelope, the layer 32.2 has a projecting transverse part 35 on the left and a hollow transverse part 36 on the right, respectively surmounting a hollow part 34 and a solid part 33 of the underlying layer 32.1 and s' fitting respectively into a hollow part 36 and a projecting part 35

  neighboring envelopes 20i-1 and 20 i + 1 of the same layer.

  A third layer 32.3 is poured in the direction of arrow F, then a fourth layer 32.4 in the direction of arrow G. The protruding and hollow parts thus formed overlap each other by alternating from one layer to the following and it follows that the sections of wrapped concrete 37 are perfectly interconnected and are separated from each other only by the flexible walls 24 and 25 strongly tightened by the

hydrostatic pressure of the concrete.

  Furthermore, reinforcements 38 are slid into the row of bags 20, preferably before pouring the concrete. In the example shown, these frames are three in number. They extend over the entire length of the row passing through small openings made in the transverse walls of the envelopes and protrude by at least one of their ends 39 the last envelope of the row considered to penetrate during the construction of the next row in the first envelope thereof and thus ensure a solid connection, after pouring and consolidation of the concrete, of the two rows aligned between

they.

  As FIGS. 4 and 9 now show, each envelope 20 is detached from the lifter 12 and its skirt 19 is then unrolled, pleated and tightened on itself in order to form the aforementioned twist intended to be knotted at 30 to close the envelope considered and subtract the section of concrete 39 corresponding to the action of water when said section is submerged, this action being particularly devastating as long as the concrete is not set and perfectly consolidated. Of course, other closure means such as adhesive tape,

  Velcro tape, staples ... can be used.

  The lifter 12 is then moved to the next location above the trench 11 to build the row which

extends it thus built.

  It is important to note moreover that the flexibility of the envelopes 20 combined with the particular technique of concreting makes it possible to embed the sections 37 well one inside the other and to ensure a perfect seat of the beam thus formed on the bottom of the excavation. or trench it and possibly against

sides of it.

  Furthermore, and as is apparent from FIG. 10, reinforcing elements 40 can be inserted transversely into the sections of the wrapped concrete 37 in order to project parallel to the sloping surface 7 of the riprap and to provide the connection of the foundation beam with the riprap 9 whatever its method of construction.

Claims (6)

R E V E N D I C A T I O N S CLAIMS   1.- Method for the construction in low water of a foundation beam (10) of a riprap (9) covering a structure (1) such as a bank, a pier or other, consisting in digging a trench (11 ) to accommodate the beam, characterized in that it also consists of: - hanging under a lifter (12) suspended from a lifting machine (13) a plurality of flexible envelopes (20) having a parallelepiped shape and arranged side by side side by side in at least one row at a spacing such that when they are filled, their adjoining transverse walls (24, 25) are strongly pressed against each other, - lower the lifter (12) until it rests on support means (21), such as easels, so that the row of envelopes is housed in the trench (11) by touching the bottom (23) thereof when filling begins, - at introduce longitudinal reinforcements (38) through the transverse walls (24, 25) of all the envelopes (20) of the row and leaving them protruding (at 39) at least from the last to ensure the connection with the next row, - pouring concrete into the envelopes, in particular by means of a pump (18) , to deposit a first layer (32.1) in one direction (arrow F) from one envelope (20) to the next in order to inflate (at 33) the transverse walls (25) in this direction, then a second layer (32.2 ) in the opposite direction (arrow G) in order to inflate (at 35) the other transverse walls (24) inversely and so on from level to level until filling is completed, - to close (at 30) the envelopes at their upper part and to unhook them from the lifter, - to move longitudinally this lifter (12) to set up at the end another row of envelopes aligned with that considered, the first envelope of this other row being pierced to receive the protruding ends of 263'9380   reinforcements of the already cast row.   2.- Method according to claim 1, characterized in that it consists in rolling a skirt (29) of each envelope (20) located above the handles (28) attached to the lifter (12), in order to allow the casting concrete, and after filling, unroll the skirt, then pleat it and tighten it on itself to form a twist and tie this twist (at 30) to close the corresponding envelope.   3.- Method according to claim 1 or 2, characterized in that on the side of the slope of the riprap, transverse reinforcing elements (42) are inserted into the envelopes filled before setting of the concrete, these reinforcing elements being intended to allow   the connection of the beam with the protective layer of said riprap.   4.- Foundation beam of the foot of the riprap of a structure such as a bank, a pier or other, obtained by the implementation of the method according to claim 1 or 2 and characterized in that it is constituted by a plurality of aligned sections of concrete filling flexible envelopes closed and separated from each other by the compressed walls of these envelopes, each section having, at the same level on one side, projecting transverse parts fitting into hollow transverse parts of the contiguous section and, on the other side, hollow transverse parts, the projecting parts being separated on the same side, from one level to the next, by parts hollow.   5. Beam according to claim 4, characterized in that all the sections of enveloped concrete are crossed by common longitudinal reinforcement, at least one end of which projects. 6.Beam according to claim 5, characterized in that reinforcing elements are inserted into the sections of concrete covered in order to protrude according to the slope of the riprap for the   connection of the foundation beam with the riprap.