EP1045089A1 - Masonry structure and associated reinforcement method - Google Patents

Abstract

The system may be used in old churches with stone vault ceilings (10) where the mortar between the stones (14) of the vault deteriorating. It pins the stones and holds them in position. Bores are drilled in each stone from the top surface (17) to withi short distance of the bottom surface (16) and a pin (19) is anchored in each bore. The top ends of the pins extend a considerable distance above the top surface of the vault. A synthetic mortar or cement (1 is poured onto the top surface of the vault, to a depth sufficient to cover the top ends of the pins. The layer of mortar is strong compression, when set, and extends into the spring of the arch (11) to transfer thrust to the wall of the building. The mix is chosen to give a coefficient of thermal expansion as near as possible equal to that of the stones of the vault.

Description

The present invention relates to the field of strengthening masonry structures extending between two support points, by example a roof element or a cross member, comprising a plurality of parts mutually in compression.

Over time, such structures are likely to become degrade for various reasons, water infiltration causing degradation of stones or bricks constituting the structure, settlement of the ground causing movement of the building foundations and its superstructures, modification of the building after its construction, etc.

In a known manner, the restoration of a vault or a supporting arch vault in case of cracking, degradation, deformation, can be carried out, either by lime grout, the success of this process being random, either by replacing damaged or broken elements requiring scaffolding, or even a reconstruction of the structure. These processes impose heavy operating and implementation easements, especially delay, immobilization of the building or the civil engineering structure, cost, and do not make it possible to reinforce structures that are too busy or degraded, reliably and safely, at a reasonable cost.

In addition, in the case of vaults whose lower surface supports elements of great historical or artistic interest such as frescoes, paintings or sculptures, these processes do not allow them to be fully preserve.

The object of the present invention is to remedy the disadvantages of known methods.

The object of the present invention is to propose a method of reinforcement of masonry structure of easy, fast implementation and inexpensive, while respecting the elements which should not be modified by reinforcement.

The reinforcement method according to the invention is intended for a masonry structure extending between at least two support points distinct and comprising a plurality of parts mutually compression, each part being maintained by friction on the parts adjacent. We add on an upper surface of the structure of masonry a working element made of materials of expansion coefficients and elasticity coefficients close to those of material constituting the masonry structure, and secured to said masonry structure. This avoids any intervention on the surface lower structure which is usually one of interest historical or aesthetic.

In one embodiment of the invention, the working element is joined to a vault of the masonry structure. We call "vault" a portion of vault bounded by edges or by ribs occupying the place of edges.

In another embodiment of the invention, the structure of masonry comprising at least one arch formed of juxtaposed keyboards, the working element is secured to said arc. A vault of the masonry structure can be taken between the arch and the working element.

In one embodiment of the invention, the keys are supported by the working element.

In another embodiment of the invention, the constraints are distributed at least between the keys and the element working. They can be divided between the keystones, the roof of the masonry structure and working element.

In another embodiment of the invention, the constraints of compression are distributed between a roof structure masonry and the working element.

Advantageously, the masonry structure is joined together and the element working by means of needles sealed in drilled holes in the masonry structure and projecting into the working element.

The masonry structure according to the invention extends between two support points and includes a plurality of parts mutually compression. Each part is maintained by friction on the parts adjacent. The structure includes a reinforcing element made in materials with coefficients of expansion and elasticity close to those of the material constituting the masonry structure. The element of reinforcement is arranged on an upper surface of said structure masonry and is secured to said masonry structure.

This gives a reinforced masonry structure without intervention on its lower surface and whose reinforcement is invisible on the side of this lower surface.

Reinforcement is achieved by increasing the cross-section structure worker. Depending on the efforts to be taken up by the working element and deformations of the masonry structure original, we can provide that the working element has a section variable adapted to said efforts and thus allowing a reduction of the amount of material used to make the working element and therefore a reduction in cost. This increase in section working reduces stress on existing elements. We can even provide that the working element takes over all of the efforts and supports the parts of the masonry structure. We will be able to then provide a separation member between the working element and the existing structure, for example a sheet of felt, polyane or any other compatible material having sufficient resilience.

If one wishes to increase the cohesion between the working element and the existing structure, a reinforcing veil extending from on either side of the working element, for example on a certain width of a flat vault or a vault in order, again, to increase the inertia of the vault. The working element can be of width equal to that an arc of the masonry structure or of width greater than that of the arch, in order to increase its transverse rigidity.

According to the efforts to be resumed and the deformation of the structure existing, the working element can be provided on the whole surface or on part of the surface of the existing structure, for example on some arches of a vault, on arc portions of a vault, in console between a vault and wall, etc.

In one embodiment of the invention, a plurality of rods of reinforcement are embedded in the reinforcing element.

In one embodiment of the invention, the element of reinforcement is completed by a beam element, the element of reinforcement and the beam element being integral.

Advantageously, the reinforcing element is present under the form of at least one flat beam secured to at least part of the said masonry structure, by means of tie rods.

Advantageously, at least part of said masonry structure is fitted with tie rods capable of distributing at least part of the load towards support points, each tie being secured to said part of the masonry structure and with a fulcrum.

In one embodiment of the invention, a tie rod is sealed in a support point provided with means for distributing the traction exerted by said pulling. The means of distributing a point support can be formed by at least one reinforcement bar substantially perpendicular to the tie secured to said support point.

In one embodiment of the invention, part of the said masonry structure, subjected to transverse tensile forces is reinforced by crossed reinforcements to form a traction zone homogeneous, which may include an arc part, a pillar part and a part of the intermediate blockage between lower and upper surfaces.

We will choose to make the working element, a material with a Young's modulus more or less close to that of the existing structure according to the desired load transfer between the existing structure and the reinforcement. We can realize the element working in mortar based on synthetic resin, for example resin epoxy, whether or not loaded, with quartz, glass fibers, carbon. This mortar must be able to be used under pressure atmospheric and have a grip without shrinkage.

Needles used to secure the parts of the structure of existing masonry and the working element are made from materials with good mechanical qualities and little sensitive to corrosion, for example glass fibers, carbon fibers, aramid fibers. These needles are sealed in the existing structure by means of a synthetic resin, for example epoxy, loaded or not with sand.

The invention is perfectly suited to the reinforcement of vaults flat, of arches with semicircular arches, beyond or not, with broken arches, basket handle arches, with creeping arches or multi-lobed, resting on walls or pillars, and strengthening a masonry structure right of the kind cross or lintel made in several pieces working in compression.

la figure 1 est une vue schématique d'une voûte à croisée d'ogives;

la figure 2 est une vue schématique d'un voûte à croisée d'ogives et arcs secondaires;

la figure 3 est une vue partielle en coupe d'une voûte à croisée d'ogives selon III-III de la figure 1 renforcée selon un premier mode de réalisation de l'invention;

la figure 4 est une vue partielle en coupe d'une voûte à croisée d'ogives selon IV-IV de la figure 1 renforcée selon l'invention;

la figure 5 est une vue partielle en coupe selon V-V de la figure 3;

la figure 6 est une vue schématique en coupe d'une voûte plane renforcée selon un second mode de réalisation de l'invention;

la figure 7 est une vue schématique de dessus d'une voûte plane renforcée selon un troisième mode de réalisation de l'invention;

la figure 8 est une vue schématique en coupe d'une structure plane de maçonnerie renforcée selon un quatrième mode de réalisation de l'invention;

la figure 9 est une variante de la figure 3;

la figure 10 est une vue schématique en coupe d'une voûte renforcée selon un cinquième mode de réalisation de l'invention; et

la figure 11 est une vue schématique de dessus de la voûte de la figure 10.

The present invention will be better understood on studying the detailed description of some embodiments taken by way of non-limiting examples and illustrated by the appended drawings, in which:

Figure 1 is a schematic view of a cross vault of warheads;

Figure 2 is a schematic view of a cross vault of ribs and secondary arches;

Figure 3 is a partial sectional view of a cross vault of ribs according to III-III of Figure 1 reinforced according to a first embodiment of the invention;

Figure 4 is a partial sectional view of a cross-ribbed vault according to IV-IV of Figure 1 reinforced according to the invention;

Figure 5 is a partial sectional view along VV of Figure 3;

Figure 6 is a schematic sectional view of a reinforced flat roof according to a second embodiment of the invention;

Figure 7 is a schematic top view of a reinforced flat roof according to a third embodiment of the invention;

Figure 8 is a schematic sectional view of a planar structure of reinforced masonry according to a fourth embodiment of the invention;

Figure 9 is a variant of Figure 3;

Figure 10 is a schematic sectional view of a reinforced vault according to a fifth embodiment of the invention; and

FIG. 11 is a schematic top view of the vault of FIG. 10.

In Figure 1, the principle of a cross vault is shown. warheads comprising two arcs 1 and 2 mutually perpendicular and cruising in their centers. The vault is limited on its edges 3 to 6, either by walls, either by double arches or former arches.

In Figure 2, we see that we added secondary arcs 7 cooperating with ivy 8 and 9.

The invention applies to all types of masonry structure resting on two support points and working in compression, by example a vault according to FIG. 1 or 2, or other types of vaults, vault sexpartite warheads, flat arch, or straight structure working in compression, whatever the material in which the structure, bricks, different types of stones, granite, sandstone, limestone, etc.

In Figure 3, we see a portion of stone vault 10 supported by a pedestal 11 surmounted by a sideboard wall 12. The portion of vault 10 comprises an arch 13 formed of a succession of keystones 14 juxtaposed and whose separation planes pass through the axis of the arch 10. Each key 14 is put in compression between the neighboring keys and by said neighboring keystones as well as by the load of the arch 10. The keyboards 14 are generally provided with mortar joints ensuring a maximum friction between the different keys 14. The arch 10 also includes a portion of vault bounded by arches and called vault 15. The vault 15 is of reduced thickness compared to the arc 13 on which it rests.

In most monuments and constructions, the lower surface 16 of the vault 10 is visible to the public, while the upper surface 17 is not not, being covered with a floor or roof. A working element 18, made of synthetic mortar, is poured on the upper surface 17 of the vault 10 in line with the arch 13. The working element 18 is firmly secured with each key 14 by means of needles 19, for example in resin epoxy loaded with glass fibers.

The working element 18 and needles 19 are fitted as follows. We start by clearing the upper surface 17 at the right of the arc 13 of any annoying element such as a cracked coating or waste various. From the upper surface 17, we dig into each keyway 14 at minus a blind hole in which we come to dispose a needle 19 which we seals with a synthetic resin composition, for example epoxy.

Part of the needle 19 is left projecting relative to the key 14. The depth of the blind hole and therefore the length of sealing of the needle 19 are determined according to the load at support by said needle 19. In the event of a very heavy load, it is possible to provide several needles 19 per key 14.

Then, we come to cover the upper surface 17 to the right of the arc 13 with a synthetic mortar to form the working element 18. The ends needles 19 projecting from the upper surface 17 are embedded in the synthetic mortar forming the working element 18. The section of the working element 18 is calculated according to the constraints of compression to be supported. The working element 18 can be at variable section in order to adapt to variations in constraints.

Thus, whatever the type of arch to be reinforced, the element working 18 makes it possible to reduce the stresses that must be borne by existing elements. Depending on the type and state of degradation of the vault, we can choose to share the compression constraints between the working element 18 and the arc 13 as can be seen in FIG. 3. The synthetic mortar intended to form the working element 18 is then directly cast onto the keyboards 14 to promote good adhesion between these two elements. Reinforcement reinforcements 27 can be embedded in the working element 18 to increase its characteristics mechanical. The frames 27 can be made of material synthetic, of the epoxy resin type reinforced with glass fibers or carbon.

In other cases, for example if the vault is strongly degraded, the working element 18 must take up all the constraints of compression and support each key 14 of the arc 13. We then have a separator 20 between the upper surface 17 and the working element 18 in order to avoid that the arc 13 does not support efforts. The separator 20 can be presented in the form of a membrane, for example of felt or polyane.

If the vault 15 still has good characteristics mechanical, we can choose to make it bear part of the constraints. As can be seen in FIG. 5, the separator 20 is disposed between the working element 18 and each key 14 of the arc 13. We on the upper surface 17 of the roof 15 and on the outer surface of the working element 18 a glass or laminate fabric forming a veil of reinforcement 21 and which extends over part or all of the roof 15 in in view of its participation in the resumption of compression constraints. The reinforcement web 21 can be produced by a succession of layers of canvas fiberglass and resin, possibly including panels honeycomb sandwich.

To improve the joining of the roof 15 and the element working 18, it is also possible to provide stiffeners 22 disposed between a part of the reinforcement veil 21 in front of the roof 15 and another part of the reinforcement web 21 in contact with the working element 18. The stiffeners 22 can be arranged at regular intervals, for example on the cob with a predetermined angle relative to the working element 18 and can be made of any inert material capable of withstanding tensile stresses, for example in aramid fibers.

If we want the keyboards 14 also participate in the recovery of compression stresses, the element of reinforcement 18 illustrated in FIG. 5, omitting the separator 20.

Another type of vault is illustrated in FIG. 6. This vault 10 is provided with a lower surface 16 of circular shape and a flat upper surface 17. The arch 10 is therefore of variable thickness, smaller in the center and more strong on the edges. We then drill blind holes of suitable length to penetrate into the stones or bricks forming the lower surface 16 of the vault 10. These stones or bricks can be either keystones if the vault 10 is an arch, or roof elements if the arch 10 is a flat arch not ribbed. In these blind holes of variable depth, we come arrange and then seal needles 19 of suitable length to project beyond the upper surface 17, then we pour the synthetic mortar forming the working element 18. Reinforcement reinforcements 27 can be embedded in the working element 18 to increase its mechanical characteristics.

In the embodiment illustrated in FIG. 7, the arch 10 is flat and thin, the upper surface 17 being convex. As previously, we dig blind holes in which we come to pose and seal needles, not shown. The holes and needles are short length due to the small thickness of the vault 10. We therefore provides for a large number in order to be able to ensure the necessary recovery compression constraints. Then we come to sink the mortar synthetic forming the working element 18. To ensure rigidity satisfactory to the working element 18, it is given a form of network, for example square, comprising parallel longitudinal portions 23 to each other and arched portions 24. It is possible, for a vault given, locally vary the space between portions 23 and 24 of the working element 18, and / or their sections, to adapt their performance to the constraints to be taken up. To further increase the rigidity of the working element 18, we can use so advantageous, the reinforcing web 21 illustrated in FIG. 5, which will allow to form a sort of shell for reinforcing the vault 10 and, in the extreme cases, arch support 10.

In Figure 8, we see a masonry element of straight shape working in compression and comprising a plurality of keys 26 in bevel shape to ensure their mutual wedging and a operation similar to that of a vault. Each key 26 is drilled one or more blind holes in which is arranged and sealed a needle 19 protruding above the keyway 26. A working element 18 is installed by grouting a synthetic mortar above said keys 26 and coats the free end of the needles 19. Preferably, a needle 19 is oriented with an angle between the angle of one of the faces of the bevel and the angle of the other face.

The variant illustrated in Figure 9 is close to the figure 3. A separator 20 is placed between the upper surface 17 of the arc 13 and the element working 18. Reinforcement reinforcements 27 are arranged in the working element 18. The frames 27 have the form of straight bars rigid, substantially cylindrical in diameter on the order of 10 to 30 mm. There are several frames 27 so as to match the general shape of the working element 18 while maintaining the said armatures 27 embedded in the working element 18 and intersecting in the cutting plane while being shifted in depth.

FIG. 10 illustrates a particular embodiment of the invention. A vault 28 covering a square piece is supported in its center by a pillar 29 and on its outer edges by walls 30. The upper surface 31 of the vault 28 is formed by the floor of the floor superior. The lower surface 32 is formed by arches and vaults. Between upper surface 31 and lower surface 32, or more precisely between the floor of the floor superior and arches and vaults, a blockage 33, often heterogeneous, is arranged and used to fill the space and load the vault 28. In this type of structure, there is often a deformation of the lower surface 32 and a pillar settlement 29.

A working element 34 in the form of one or more beams is arranged in one or more recesses dug in the upper surface 31 and extends into the walls 30. Needles, not shown, can be arranged to secure the working element 34 and / or the arches or vaults of the lower surface 32. Rods 35 are fixed to an upper end in the working element 34 and at one end lower in pillar 29, for example at a height between the lower surface 32 and the upper surface 31. The tie rods 35 are distributed over all or part of the length of the working element 34. The tie rods 35 are formed in the same material as the needles and sealed in the same way.

The portion 29a of the pillar 29 in which the ends are fixed lower ties 35 is subject to significant stresses traction in a horizontal plane. In addition, many tie rods 35 are fixed by sealing in the portion 29a. To take up these constraints, an armed complex 36 (FIG. 11) is formed in said portion 29a and in its neighborhood. The armed complex 36 comprises a plurality of rods 39 crossed comprising glass, carbon or other fibers and having mechanical characteristics adapted to traction. Rods 39 are arranged in substantially horizontal holes drilled from the lower surface 32 at the portion 29a. Rods 39 are sealed with the same way as the needles, in the portion 29a, the blocking 33 and the arcs or vaults of the lower surface 32. The armed complex 36 forms an area suitable for resist transverse tensile forces and receive the anchorage of the lower end of the tie rods 35.

For the simplicity of the drawing in FIG. 11, the working element 34 and the tie rods 35 have not been shown. Tie rods 37, or sheets of tie rods, are fixed to an upper end in the walls 30 and to a lower end in pillar 29 at the level of the armed complex 36. holes are drilled in the walls 30. The upper end of the tie rods 37 is sealed over almost the entire thickness of the walls 30. The tie rods 37 are made of material similar to needles and can reach sections of several square centimeters to resume efforts important. The sealing is carried out in the same way as for the needles. Prestressing can be applied to tie rods 37.

A wall 30 is a heterogeneous set of stones or bricks of various dimensions and mortar. Its resistance to tensile forces exerted by a tie rod 37 is difficult to model and, a priori, weak. To avoid tearing away stones or bricks from said walls, 30 plans to reinforce it in the following way, before installing the tie rods 37.

One or more horizontal holes are drilled in the direction of length of a wall 30 substantially perpendicular to future tie rods 37. Rods 38 of the same type as tie rods 37 are placed there and sealed there. of suitable dimensions. Prestressing can be applied to them. The area in which the rods 38 are arranged has cohesion high. The forces exerted by the tie rods 37 can be distributed in the said zone without risk of tearing stones or bricks. Thanks to the rods 38, we form a kind of horizontal beam inserted into each wall 30 and constituting a force distributor.

The area in which the rods 38 are arranged is, of all ways, stabilized by the mass of the parts of the walls 30 located at a level higher and exerting a compressive stress. To favor the distribution of forces, we can increase the number of tie rods 37 by reducing their unit section and arranging them in a fan from the armed complex 36.

Alternatively, one can design a reinforcement only based tie rods 37, rods 38 and reinforced complex 36.

So, we have a reinforcement process and a structure of masonry extending between two support points and comprising a reinforcement element made with materials of expansion coefficients and elasticity close to that of the material constituting the structure masonry, secured to said masonry structure, at least part of said masonry structure being provided with suitable tie rods to distribute at least part of the load to support points, each pulling being secured to said part of the masonry structure and with a fulcrum. We can thus reduce the compression load exercising on one point of support and transferring it to others.

A tie rod can be sealed in a fulcrum provided with distributors of the tensile forces exerted by said tie rod.

Thanks to the invention, a masonry structure is obtained considerably strengthened to the extent that its stiffness is proportional to the cube of the height of its working section.

The invention is perfectly suited to any structure whose bottom surface must be protected, both during the work of reinforcement only at the end of these.

Claims (17)

Method for strengthening a masonry structure extending between at least two distinct support points and comprising a plurality of parts mutually in compression, each part holding by friction on the adjacent parts, in which we add only on an upper surface of the masonry structure an element working on the basis of synthetic resin produced in materials of coefficients of expansion and elasticity close to those of the constituent material the masonry structure, and secured to said structure of masonry. The method of claim 1, wherein the structure of masonry comprising a vault, the working element is secured with the said vault. The method of claim 1, wherein the structure of masonry comprising at least one arch formed of juxtaposed keyboards, the working element is secured to said arc. The method of claim 3, wherein a roof top of the masonry structure is caught between the arch and the working element. Method according to any one of claims 3 or 4, in which the keys are supported by the working element. Method according to any one of claims 3 or 4, in which the compression stresses are distributed at least between the keyboards and the working element. The method of claim 6, wherein the constraints are distributed between the keyboards, the roof structure masonry and the working element. Process according to any one of Claims 1 to 5, in which the compression stresses are distributed between a roof of the masonry structure and working element. Method according to any of the claims previous, in which the masonry structure is joined and the element working by means of needles sealed in drilled holes in the masonry structure and projecting into the working element. Masonry structure (10) extending between two points support (11) and comprising a plurality of parts (14) mutually compression, each part being maintained by friction on the parts adjacent, characterized in that it comprises an element of reinforcement (18) made from synthetic resin with materials expansion and elasticity coefficients close to those of the material constituting the masonry structure, arranged only on one surface upper (17) of the masonry structure, and secured to said masonry structure. Structure according to claim 10, characterized in that that a plurality of reinforcing rods are embedded in the element of enhancement. Structure according to claim 10 or 11, characterized by fact that the reinforcing element is completed by a beam element, the reinforcing element and the beam element being integral. Structure according to claim 10 or 11, characterized by causes the reinforcing element to be in the form of at least a flat beam secured to at least part of said structure masonry, using tie rods. Structure according to any one of Claims 10 to 13, characterized by the fact that at least part of said masonry structure is fitted with tie rods capable of distributing at least part of the load towards support points, each tie being secured to said part of the masonry structure and with a fulcrum. Structure according to claim 14, characterized in that that a tie rod is sealed in a fulcrum provided with means of distribution of the tensile forces exerted by said drawing. Structure according to claim 15, characterized in that that the means for distributing a support point are formed by at least a reinforcement bar substantially perpendicular to the tie secured to said support point. Structure according to any one of Claims 10 to 16, characterized by the fact that part of said masonry structure, subjected to transverse tensile forces is reinforced by crossed reinforcements to form a homogeneous traction zone.

Images