FR2748044A1 - SINGLE-PIECE CONCRETE SHELL BLOCK, MOLD FOR THE PRODUCTION OF SUCH A BLOCK - Google Patents

Abstract

The invention relates to a one-piece molded concrete shell block for the protection structure of maritime and river works having an exterior surface (6) of general shape defining a smooth polyhedron (3), according to the invention, at least part of the outer surface (6) of the block has protuberances (4) and / or grooves (5) originating from molding, the protuberances (4) and / or grooves (5) having faces in planes intersecting at the local general plane of the smooth polyhedron (2).

Description

SINGLE-PIECE CONCRETE SHELL BLOCK, MOLD FOR

PRODUCTION OF SUCH A BLOCK

  The invention relates to a one-piece molded concrete shell block for a structure for protecting maritime and river works against waves and currents, and

  a mold for the production of such a block.

  The technical characteristics sought in terms of artificial blocks are firstly the stability

  hydraulic and on the other hand robustness.

  In addition to these technical characteristics, the goal of block designers is to reduce the volume of concrete required for a given shell while having stability and robustness in accordance with their use. For this, the designers play on the dimensions and the angles of the constituent parts of the block in order to increase the volume of the

  empty spaces between nested blocks.

  The tendency of designers is to modify the dimensions and general shapes of the legs or anvils constituting the block so as to generate a strong nesting while having more empty spaces in the nests of blocks. In this regard, we can compare the block of document US-A-4347017 dating from the 80s, with the more slender block of document US-A-5441362 more recent. In addition, in order to reduce the volume of concrete on each

  block, the shapes of the blocks are slender.

  This has the effect of weakening the legs of

  blocks which are then more elongated.

  The resulting blocks give a significant concrete saving result. However they are less robust and because of this, in the long term, there may appear in the shell a covering defect causing, due to the broken blocks settling, exposing part of the maritime and fluvial works and being able to be at the origin of

damage.

  One of the aims of the present invention is to maintain the optimal dimensional ratios of the existing blocks and to produce an uneven relief on the block surfaces, without influence on the structural strength, constituting a plurality of asperities. In this regard, the present invention completely opposes the general idea that, in order to facilitate its manufacture, and in particular demolding, the shell blocks made of one-piece molded concrete must have a smooth outer skin originating from molding. All of the existing one-piece molded concrete shell blocks

  currently are smooth-skinned from molding.

  To this end, the invention relates to a one-piece molded concrete shell block for the protection structure of maritime and river works having an exterior surface of general shape defining a smooth polyhedron. According to the invention at least a part of the external surface of the block has protuberances and / or grooves molded in the mass of the block, the protuberances and / or grooves having faces in planes generally intersecting

local of the smooth polyhedron.

  The rugged terrain increases the bonding coefficient between blocks, and therefore increases the coefficient of hydraulic stability. The coefficient of attachment being increased, the elementary inertia of the block (mass of concrete for a block) can be reduced, the reduction in the mass of each block being compensated for by the best attachment between blocks. This allows a saving of concrete on the realization of a given surface of shell. The faces of the protrusions and / or grooves are as many secondary planes of different orientations which multiply the possibilities of plan-to-plane contact stabilized between blocks with respect to the surfaces. smooth of

prior art.

  The multiplication of the possibilities of plane-to-plane stabilized contact between blocks induces an increase in the

  volume of empty inter-block spaces.

  Therefore, with the same number of blocks we obtain a shell of larger surface area while retaining a

  group effect equivalent to the prior art.

  Environmental criteria increasingly require that artificial structures are best integrated into the natural environment of the place where they are installed. In this respect, the one-piece molded concrete shell blocks with smooth skin do not meet these criteria and distort the sites where they are used. On these sites it is then necessary to use natural riprap from quarry. However, the opening of quarries is also strictly regulated and the transport of natural rockfills of suitable size is a source of nuisance (traffic, noise,

  pollution, installation of access infrastructure etc ...).

  It is therefore another object of the present invention to propose one-piece molded concrete shell blocks according to the invention having protuberances and / or grooves, originating from molding, of general shape similar to the general shape of the natural asperities of the type of site rock

  o they are installed (geomorphism).

  To this end, the invention relates to a shell block of one-piece molded concrete having protuberances and / or grooves, originating from molding, placed in a place having a given geomorphism. According to the invention the protrusions and / or grooves, originating from molding, have a general geomorphism substantially equivalent to the geomorphism

  roughness of the place considered.

  In addition to the general advantages of the blocks according to the invention, the block having this characteristic has the advantage of replacing natural riprap without damaging the site, and by limiting the constraints linked to the supply and delivery of natural riprap

to the site.

  Advantageously, the concrete constituting the block can be colored in the tones of the geological environment of the place considered. The invention also relates to a mold for producing a block according to the invention. Other advantages and features of this

  invention will result from the description which follows

  reference to the accompanying drawings in which: FIGS. 1A to 1C are schematic views of a

block according to the invention.

  FIGS. 2A to 2D are schematic views of an exemplary embodiment of a block according to the invention with

granitic geomorphism.

  FIGS. 3A to 3D are schematic views of an exemplary embodiment of a block according to the invention with

basalt geomorphism.

  The blocks proposed in example are blocks having for smooth polyhedron the form of the blocks of US-A-4347017 however these examples intended for illustration the

  description are in no way limitative of the basic type of

blocks according to the invention.

  The invention relates to a block 1 of a one-piece molded concrete shell for a structure for protecting structures.

maritime and fluvial.

  This block i is made up of legs 2 arranged together

  according to angles and inter-leg deviations given.

  This block 1 has an exterior surface 6 of general profile defining a smooth polyhedron 3. Smooth polyhedron 3 is the smoothed surface of the exterior profile of the block. In the prior art, this smooth polyhedron corresponds to the surface

  gross external formwork release.

  According to the invention, at least part of the outer surface 6 has, relative to the smooth polyhedron 3,

  protrusions 4 and / or grooves 5 from molding.

  It is clear that the surface defects resulting from the formwork of a smooth mold of the prior art do not constitute the protrusions 4 and / or grooves 5 of the block 1

according to the present invention.

  For a block 1 according to the invention, the smooth polyhedron 3 of block 1 is an imaginary polyhedron corresponding to the exterior surface of an equivalent block which would have been poured into a

smooth mold.

  The protrusions 4 and / or the grooves 5 are due to grooves and / or protrusions voluntarily produced in the

mold (not shown) of block 1.

  Advantageously, the mold (not shown) can be the smooth mold of the equivalent smooth-skin block in which protuberant elements have been added comprising or generating grooves between them, so that when the concrete is poured into the mold, this results , in positive,

  grooves 5 and protrusions 4 on block 1.

  Thus it is well understood that, while respecting the optimal proportions of an equivalent smooth block, the elementary volume of concrete necessary for the production of a block 1 according to the invention is reduced by the volume of the protruding elements added to the mold, these protruding elements creating on the block 1 grooves 5 and protuberances 4 coming, due to the increase in the coupling coefficient, to overcome the mass defect

  elementary of block 1 compared to its smooth equivalent.

  These protrusions 4 and / or grooves 5 have constitutive faces in planes intersecting at the local level of the smooth polyhedron. This therefore considerably increases the number of planes in which the nested blocks 1 are

  likely to find themselves in stabilized support.

  The resulting overlap presents larger inter-block void spaces than with smooth skin blocks

  while preserving the group effect of the shell.

  FIGS. 2A-2D and 3A-3D represent two examples of blocks according to the invention on which the protuberances 4 and / or the grooves 5 have a similar geomorphism with a granite site and a basalt site respectively. In this way, the blocks according to the invention are integrated into

  their deposit site without misrepresenting it.

  The geomorphic block can advantageously be dyed in the mass in a tone similar to the geological colors of the site in which it is deposited. Advantageously, the mold according to the present invention can be a rehabilitated smooth mold. The production of such a rehabilitated mold can comprise the following steps: A homothetic smooth block is produced with a volume less than the volume of the smooth mold to be rehabilitated, so that there is a vacuum thickness between the mold

rehabilitate the block.

  In a first embodiment, the protuberances and the grooves are sculpted directly on the block; then the sculpted block is kept centered in the mold and a moldable material is poured between the sculpted block and the smooth wall of the mold. A reproducible block molding is thus obtained, and perfectly integrated into molds

smooth to rehabilitate.

  In a second embodiment, the smooth block is coated with a thickness of easily shaped material in which the protuberances and the grooves are shaped; then the block with shaped outer layer is kept centered in the mold and a moldable material is poured between the block with shaped outer layer and the smooth wall of the mold. A reproducible block molding is thus obtained, and perfectly integrated into molds

smooth to rehabilitate.

  Of course, the invention is not limited to the embodiments described and shown, but it is susceptible of numerous variants accessible to a person skilled in the art without departing from the invention. In particular, without departing from the scope of the invention,

  replace the smooth base block with any other known block.

  Similarly, without departing from the scope of the invention, it is possible to decline blocks having geomorphisms similar to other natural geomorphisms than granitic or basaltic.

Claims (4)

  1. One-piece molded concrete shell block for the protection structure of maritime and river works having an exterior surface (6) of general shape defining a smooth polyhedron (3), characterized in that at least part of the exterior surface ( 6) of the block has protuberances (4) and / or grooves (5) originating from molding, the protuberances (4) and / or grooves (5) having faces in planes intersecting the plane   general general of the smooth polyhedron (3).   2. Shell block according to claim 1 arranged in a place having a given geomorphism, characterized in that the protuberances (4) and / or the grooves (5) of the block have a geomorphism substantially equivalent to the geomorphism of the protuberances and / or the natural gorges of the place considered.   3. Shell block according to claim 2 characterized in that it is dyed in the mass in the tones of the place considered.   4. Mold for one-piece molded concrete shell block, characterized in that it comprises protruding elements comprising or forming grooves between them so as to produce the grooves (5) and / or the protuberances (4) of a block of one-piece molded concrete shell according to   any one of claims 1 to 3.