FR2531733A1 - METHOD AND DEVICE FOR EXTRACTING A FORMWORK IN THE CONTEXT OF PRODUCING A MOLDED WALL IN THE GROUND - Google Patents

Abstract

1. Process for the withdrawal of a shuttering element (3) used in making a panel (P) of a wall moulded in the ground, said shuttering element comprising a shaped central portion whose outline corresponds to the pattern to be imparted to the end of the panel to be made, and two wings (4) extending on both sides of said central portion, characterized by the following steps : - providing such a shuttering element (3) which protrudes above the ground surface ; - fitting on the protruding portion of said shuttering element an implement comprising a body (1) and two shaped parts (2) forming side grooves which are slidable upon the wings of said shuttering element, the lower portion (6) of said shaped parts being bevelled so as to form a dismantling wedge ; - imparting a beating motion to the implement so as to force the wedge-shaped parts between the concreted panel and its shuttering element until their introduction therebetween ; and - pursuing said beating motion so as to drive the implement deeper and deeper until complete release of the shuttering element.

Description

The invention relates to a method and device for extracting a

  formwork as part of the realization of a

molded wall in the ground.

  The walls molded in the ground are executed conventionally by elementary panels, either alternating or successive. In either case, it is usually put in place

  c 8 earth, that is to say at both ends of the primary rings

  mayors in the case of killed by alternate panels, to-

  one end of the panels in the case of a realization by successive panels, a formwork to obtain a generally concave impression over the entire height of the panel

  The next panel is then excavated and concreted

  the impression thus made, of course after removal of the formwork, which makes it possible to obtain a geometrically well-defined joint. The forms used to date have transverse sections of various shapes, the simplest of which is a circle. two types of implementation

radically different work.

  Forms of the first type 2 used so

  very general, are intended to be extracted as safe-

  slippery, that is to say by pulling in the direction of their length It is therefore imperative to extract them before the complete setting of the concrete, otherwise the adhesion forces are much

  too much to hope for a break in these

  However, after a beginning of stiffening of the concrete to avoid the collapse of the latter in the vacuum resulting from the extraction of the tube O It is conceivable that the choice of the right moment for this extraction is always delicate

  because it depends on many factors of varying importance (

  tare and dosage of cement, temperature, concreting speed, etc.). In addition, this mode of extraction, because it is

  (related to concreting operations, seriously complicates

  construction, the operation being imperative-

  carried out without interruption, whatever

  incidents or accidents that may occur.

  Finally, slippery formwork systems do not allow

  Not the current implementation of complementary sealing elements of the "water-stop" type between two panels

  consecutive, these organs do not support the extraction of the cof-

  which subjects them to longitudinal tensile stresses

  and, as a result, the risk of tearing or tearing

  while they are barely sealed in concrete that

just take her hold.

  On the other hand, the empty volume left at the end of the panel by the extraction of the formwork facilitates the execution of

  excavation of the following consecutive panel Indeed, the

  excavation is naturally guided in the empty volume thus reserved guaranteeing the geometric continuity of the wall It can even remove me without major difficulties

  areas of concrete that may have been able to circumvent the

  in favor of geometrical irregularities in the excavation

  tion in which the panel previously made was molded.

  The forms of the second type also allow

  to obtain an impression generally concave over the entire height of the concrete panel but are not extracted as

  slippery forms before the complete setting of the concrete.

  A formwork of this second type is left in place until

  taking of the latter and the excavation of the

  next tif is carried out until it is in contact It is then

  lateral displacement, for example as a result of

  state of a pressure inflation of flexible tubes prevailing over the entire height of the formwork on the face of the latter being on the concrete side A formwork of the second type is

  describes, for example, in the French patent application

  No. 2,473,091 of the Applicant.

  This type of formwork, unlike the previous type

  dent, allows to completely get rid of the subjections

  result from the practical conditions of concrete concreting

  water supply, considerably simplifying the organization of worksites.

  It also makes it possible to install sealing members of the "water stop" type, given its method of extraction by

lateral displacement.

  However, this type of formwork being left

  place during the excavation operations of the panel

  cutif following it no longer exists at the end of the panel

  preceding empty volume allowing the guidance of

  excavation trench with the corresponding risks of

  deviation and, consequently, of geometric continuity de-

  fectuous wall. The choice of a concave section for the part

  of formwork lying on the ground side for the purpose of

  constitute an empty volume on the side of the panel to be excavated

  the following does not provide a sufficiently secure solution.

  Indeed, during concreting, the concrete risks

  the empty volume that we wanted to reserve, at the

  geometric irregularities more or less inevitable

  excavation tables, the result in such a case is that not only the guidance sought can not be

  obtained but that the removal of the said circumvention of

  your tone is an additional difficulty.

  The present invention aims to provide a method and device combining the advantages of both

  types of formwork previously described while not

  not so much the disadvantages, and going even further

  simplification of construction and use of

  lisation. The invention is intended to be implemented with a formwork element comprising a central portion

  profile whose profile corresponds to the usual

  concave, which one wishes to impart at the end of the ei panel to achieve, two wings located on both sides

from the central part.

  The wings may be flat or profiled

  The wings can form an angle with the

  those of the central part or be located in the prolongation

of these.

  The method of the invention comprises the following steps: providing a formwork element of the kind mentioned above which projects relative to the surface of the ground; mount on the portion of the formwork element making

  protrudes a tool comprising a body and two parts pro-

  spun yarns forming lateral grooves that slide

  on the wings of the formwork element, the lower part

  upper profiled pieces being beveled to form forming corner; -printing the tool with a threshing movement so as to force the parts of the wedge-shaped pieces between the

  concrete panel and its formwork element up to

  corners between the concrete panel and the formwork element; continue the threshing motion to push the tool deeper and deeper until it detaches

complete shuttering element.

  The invention also covers the tool used in the

  implementation of the process of the invention and defined above.

  According to a preferred embodiment, the body of the tool has at its lower part a blade to scrape the non-concrete face of the formwork element, this blade may optionally include teeth The role of this blade is to eliminate all the concrete packages that

  could have circumvented the formwork element during the

  At the same time, it ensures the role of

  possible excavation of the excavation where the panel will be

  efore. The threshing movement can be imparted to the tool by a winch which, alternatively, raises the latter and then lets it fall back with all its weight In this case, the tool must have a large mass, for example at least one

  in order to be effective Most of the time, the tool will be

  made of steel We can, sid sire, incorporate a ballast in

lead.

  The shape of the body of the tool is not critical.

  It can be full or hollow (for example open to its

  these upper and lower so as to allow the-free

passage of the excavation mud).

  Alternatively, one could use a threshing device with compressed air incorporated into the tool itself, or

  use an auxiliary threshing device, such as a

  your coming hitting the tool and pushing it gradually between

  shuttering element and concrete.

  According to yet another variant, the body of the

  It is formed by the excavation bucket itself. For this purpose, it is sufficient to mount on one of the songs of the skirt of the excavation bucket, the grooves forming wedges so as to allow the guidance of the bucket on the bucket. formwork element The bucket is used in the open position, the leading edge of the bucket of the bucket located on the side of the formwork element playing

  then the r 8 of the optional scraping blade mentioned above.

  the following description with reference to the drawings

  annexed given as a non-restrictive example will make a good

  how the invention can be achieved, the particulars

  rities that emerge from both the drawings and the text

  of course, part of said invention.

  FIG. 1 is a side view of a tool according to

  the invention, mounted on a formwork element.

  Figure 2 is a sectional view along the line II-II

of Figure 1.

  Figure 3 is a sectional view along the line III-III of Figure 20

  Figures 4a, 4b, 5, 6a and 6b illustrate schema-.

  the implementation of the process of the invention in the

  part of the execution of a wall molded in the ground, the figures

  res a, 5 and 6 a are partially sectioned elevational views while FIGS. 4 b and 6 b are horizontal sectional views in accordance with FIGS.

  lines b-b of Figures 4a and 6a, respectively.

  FIGS. 1 to 3 show a tool for de-

  formwork according to the invention O This tool comprises a body 1, for example solid steel, a large mass (1 tonne and more) and two profiled side parts 2 integral with the body and constituting vertical grooves that can be mounted and slide on the formwork element 3, more particularly

  on the wings 4 of it, as can be seen from the

  20 It should be noted that the width of the formwork element must be less than the width of the excavation so as to

  on each bank, a game of the order of 2 to 3 cm

  both the sliding of the tool of the invention.

  The lower part of the body 1 is conformally shaped

  5 to form a blade 5 which is in scraped contact with the face of the non-concreted formwork element. From their side, the parts 2 forming guide grooves of the tool on the flanges 4 are bevelled at their lower part. 6. The tool may be suspended from the cable of a winch by ears such as 7 provided at the upper part of the body. The implementation of the process of the invention with

  the tool of Figures 1-3 is illustrated in Figures 4-6.

  FIGS. 4 a and 4 b show a wall molded in the ground in the course of execution. More particularly, there is seen a panel P which has just been made with the shuttering element 3 still in place at its end. The excavation E in which will be poured the next panel was also

  conventionally carried out under bentonite sludge (not

  Preventing possible ground loops The height of the formwork element 5 is greater than the depth of the excavation so that it protrudes above the solo

  A projection of the order of 1 to 2 meters is generally suf-

  cient. The formwork element 3 used has a convex body C so as to leave a concave impression in the concrete of each panel. A longitudinal slot provided in the body C allows the installation of a conventional seal J of the "type". When it is desired to proceed with the extraction of the shuttering element 3, the tool of the invention is mounted on the part of the element which projects above the ground, the wings 4 being engaged in the grooves 2 so that the tool can slide, with positive guidance, along the formwork element The tool is suspended from a winch by a target 8, as shown

  We print a threshing action to the tool in

  lifting and letting down with all its weight, alternative-

  As a result of this action, the bi-lateral

  wedge shaped 6 wedges fit between the concrete panel

  and the shuttering element and cause the detachment of

  it progresses as the tool progresses towards the 4 'und of the trench During this progression, the blade 5 destroys any concrete packets that could have been destroyed.

  bypassing the shuttering element during the casting of the

  P, have not already been eliminated during the realization of the excavation E, and could be a problem with the extraction of the formwork element This blade allows

  also the possible recalibration of the excavation E if

  it was a little removed from its theoretical position O When the tool reaches the bottom of the excavation, the formwork element is released over its entire height and can be extracted

  It is often necessary, even before the end of the opera-

  tion, insure the formwork element on the surface by means of a cable such as 9, to prevent an uncontrolled tilting of it in the excavation E. During the extraction operation, the seal J does not no risk of damage,

  Thus, in a single operation, two ob-

  fundamental objectives: the extraction of the formwork element; the geometrical continuity of the wall, the recalibration of the excavation of the next panel by means of the tool guided on the shuttering element put in place during the execution of the previous panel, guaranteeing the absence of any deviation

  in the direction perpendicular to the general plane of the wall.

  We can not wait for the end of the ex-

  cavation of the next panel to use the tool of the invention.

  if, because of the nature of the land crossed, the

  Diversion risks are important.

  We will then carry out the excavation

  by successive vertical passes of a few meters in

  alternating the use of the tool of the invention with

that of the excavation bucket.

  Extraction of the formwork and geometrical continuity

  of the wall can also be realized in the case where two consecutive wall panels must form between them a certain angle as, for example, for the realization of polygonal contours It would be enough for this to modify

  the geometry of the tool accordingly.

  It goes without saying that the described embodiments

  are just examples and that it would be possible to

  to change, in particular by substitution of technical equivalents, without departing from the scope of the invention. In particular, it is possible to combine the

  method of the invention with the use of the decoding device.

  inflatable tube shoe which is the subject of the application for

  French patent published No. 2,475,091 of the Applicant.

Claims (2)

  1 Method of extracting a formwork element used during the production of a constituent panel   of a wall molded into the ground, this formwork element   bearing a profiled central part (3) whose profile corresponds to the impression that is to be imparted at the end of the panel to be produced, and two wings (4) located on the side and   of the central part, characterized in that it   takes the following steps: providing a formwork element of the above kind which protrudes from the ground surface; mounting on the portion of the formwork element projecting a tool comprising a body (1) and two parts   profiles (2) forming lateral grooves   smooth on the wings of the formwork element, the part   lower part (6) of the profiled parts being cut into two   bucket so as to form corner of formwork; print a threshing motion to the tool to force the parts of the wedge-shaped pieces between the   concrete panel and its formwork element up to   troduction of the corners between the concrete panel and the   formwork; continue the threshing movement so as to drive the tool deeper and deeper until it detaches * complete shuttering element.   2 e Tool for implementing the method of claim 1, characterized in that it comprises a body and two profiled pieces forming lateral grooves sliding on the wings of the formwork element, the lower part of the profiled parts being beveled   to form a corner of formwork.   Tool according to claim 2, characterized in that   what his body has at its lower part a vein blade   scraping the non-concreted side of the shuttering element, this blade possibly including teeth O 4 Tool according to claim 2, characterized in that   that the body of the tool is constituted by an excavation bucket.   Tool according to any one of the claims   2 to 4, characterized in that it has a mass of at least one ton.