EP1045089B1 - 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 reinforcement of masonry structures comprising at least one arc extending between two support points, for example example a vault element or a cross member, comprising a plurality of mutually compressive parts.

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

The article "Calculation, disorders, repair and modernization of bridges in masonry "by Messrs Delbecq, Michotey and Simonet, published in Works No. 561 of December 1981, describes the damage and different ways of repairing masonry bridges. In the case of disorders of the intrados of the vault, it is planned to carry out a counter-attack in shotcrete after cleaning and rejoining the intrados. The sided is anchored in the healthy parts by steel pins and armed with a welded mesh attached to these pins. In the case of a bulging of the upper part of the vault, one can proceed to dismantling and reassembling the eardrum. In the case of cracks cross-sections of the vault, it is first necessary to reinforce the foundations then, if the state of the vault is not very critical, one can be attempted to restore the monolithism of masonry by injections. he do not forget that a masonry vault fits very well Well, this remedy does not always seem useful; moreover, he risks modify the mechanical diagram of the vault making it more rigid. In besides, we do not know very well what we do by injecting a crack: where will spend the effort next? If a solution of this type is adopted, will also have to recompress the vault (dismantling and keying of the stone of key, jacking with the key). In any event, in the case of of the vault, this solution is ineffective: it is necessary to increase "the rupture coefficients "of the vault by giving it back the thickness, after possibly injecting the cracks to block them. A thickening above is achieved after disbursement of the embankment with creation of a concrete vault pinned to the vault masonry. Thickening from underneath is done with a concrete counter-shield projected or with arched metal beams which are then drowned in shotcrete or poured in progress.

In known manner, the restoration of a vault or a carrier arch in the event of cracking, degradation, deformation, may be carried out, either by slurry of lime, the success of this process being random, by replacing the degraded or broken elements requiring scaffolding, even a reconstruction of the structure. These methods imposes heavy easements of exploitation and of implementation, in particular of delay, immobilization of the building or the structure of art, cost, and do not make it possible to reinforce overworked structures or degraded, reliably and safely at a reasonable cost.

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

The present invention aims to remedy disadvantages of known methods.

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

The reinforcement method according to the invention is intended for a masonry structure comprising at least one arc extending between at least two support points distinct and comprising a plurality of mutually compression, each piece is now by friction on the parts adjacent. We add on the upper surface of the structure of masonry to the right of the arc an element made in materials of coefficients of expansion 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 inferior of the structure which is usually the one of interest historical or aesthetic.

In one embodiment of the invention, the element is secured with a vault of the masonry structure. We call "vault" means a portion of a vault bounded by ridges or ribs occupying the place of ridges.

In another embodiment of the invention, the structure of masonry comprising at least one arc formed of juxtaposed clavels, the element is secured to said arc. A vault of the Masonry structure can be caught between the bow and the element.

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

In another embodiment of the invention, the constraints of compression are distributed at least between the claveaux and the element. They can be divided between the claveaux, the vault of the masonry structure and element.

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

Advantageously, the masonry structure and the reinforcing element by means of needles sealed in drilled holes in the masonry structure and protruding into the working element.

The masonry structure comprising at least one arc according to the invention extends between two ful points and includes a plurality of pieces mutually compression. Each piece is held by friction on the parts adjacent. The structure comprises a reinforcement 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 disposed on an upper surface of said structure of masonry to the right of the arc 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 section working of the structure. Depending on the efforts to be taken up by the working element and deformations of the masonry structure of origin, it can be expected that the working element has a section variable adapted to the said efforts and thus allowing a reduction of amount of material used for the realization of the working element and therefore a reduction of the cost. This increase of the section working environment makes it possible to reduce the constraints on the existing elements. It can even be expected that the working element will take up all 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 with sufficient resilience.

If we want to increase the cohesion between the working element and the existing structure, one can provide a reinforcement veil extending from on both sides of the working element, for example on a certain width of a flat vault or vault to increase the inertia of the vault. The working element can be of width equal to that arc of the masonry structure or of a width greater than that of the bow, in order to increase its transverse rigidity.

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

In one embodiment of the invention, a plurality of rods 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 under the form of at least one flat beam secured to at least a portion of the said masonry structure, by means of tie rods.

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

In one embodiment of the invention, a tie rod is sealed in a fulcrum provided with means of distribution of the efforts of traction exerted by the said pulling. The means of distribution of a point of support may be formed by at least one reinforcing bar substantially perpendicular to the tie secured to said fulcrum.

In one embodiment of the invention, part of the so-called masonry structure, subjected to transverse tensile forces is reinforced by crossed frames to form a traction zone homogeneous, which may include a bow part, a pillar part and a part of the intermediate block between intrados and extrados.

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

The needles to secure the parts of the structure existing masonry and the working element are made from materials with good mechanical properties and little sensitivity to corrosion, for example fiberglass, carbon, aramid fibers. These needles are sealed in the existing structure by means of a synthetic resin, for example epoxy, filled or not with sand.

The invention is perfectly adapted to reinforcement vaults with semicircular arches, horseshoe or not, with broken arches, basket-shaped arches, creeping arches or multilobed arches, resting on walls or pillars, and reinforcement of a masonry structure right of the kind crosses 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 variante de la figure 3;

la figure 7 est une vue schématique en coupe d'une voûte renforcée selon un cinquième mode de réalisation de l'invention; et

la figure 8 est une vue schématique de dessus de la voûte de la figure 7.

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

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

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

Figure 3 is a partial sectional view of a warhead vault 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 vault of warheads 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 variant of Figure 3;

Figure 7 is a schematic sectional view of a reinforced arch according to a fifth embodiment of the invention; and

FIG. 8 is a schematic view from above of the vault of FIG. 7.

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

In FIG. 2, it can be seen that secondary arcs 7 have been added. cooperating with liernes 8 and 9.

The invention applies to all types of masonry structure resting on two points of support and working in compression, by example a vault according to Figure 1 or 2, or other types of vaults, vault of sexpartite warheads, flat vaults, or straight structure working in compression, regardless of 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 side 11 surmounted by a side wall 12. The portion of vault 10 comprises an arc 13 formed of a succession of clavels 14 juxtaposed and whose separation planes pass through the axis of the vault 10. Each keyway 14 is placed in compression between the neighboring clavels and neighboring knuckles and the load of the vault. 14 are usually provided with mortar joints ensuring maximum friction between the different bells 14. The vault 10 also includes a vaulted portion bounded by arches and 15. The vault 15 is of reduced thickness compared to the arc 13 on which it rests.

In most monuments and constructions, the intrados 16 of the vault 10 is visible to the public, whereas the upper surface is not, being covered with a floor or a roof. A working element 18, made of synthetic mortar, is cast on the extrados 17 of the vault 10 to the right of the bow 13. The working element 18 is firmly attached to with each key 14 by means of needles 19, for example resin epoxy filled with glass fibers.

The laying of the working element 18 and the needles 19 is carried out as follows. We start by clearing the extrados 17 at the right of the arc 13 of any annoying element such as a cracked coating or waste various. Starting from the upper surface 17, each keyway 14 is hollowed out less a blind hole in which we just have a needle 19 that we sealed by means of a synthetic resin composition, for example epoxide.

A part of the needle 19 is left protruding from the 14. The depth of the blind hole and therefore the length of sealing of the needle 19 are determined according to the load at supported by said needle 19. In case of very heavy load, it can provide several needles 19 per key 14.

Then we just cover the upper surface 17 to the right of the arc 13 of a synthetic mortar to form the working element 18. The ends needles 19 projecting from the extrados 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 to adapt to the variations of the constraints.

Thus, whatever the type of vault to be reinforced, the element working 18 reduces the constraints to be supported by the existing elements. Depending on the type and state of degradation of the vault, one can choose to share the compression constraints between the working element 18 and the arc 13 as can be seen in FIG. synthetic mortar for forming the working element 18 is then directly cast on the claveaux 14 to promote good adhesion between these two elements. Reinforcement frames 27 can be embedded in the working element 18 to increase its characteristics mechanical. The frames 27 may be made of material synthetic material, 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 keystone 14 of the bow 13. a separator 20 between the extrados 17 and the working element 18 to avoid that the bow 13 does not support efforts. The separator 20 can present itself in the form of a membrane, for example of felt or polyane.

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

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

If we want the claveaux 14 to participate in the recovery of compressive stresses, we will proceed with the installation of the element of reinforcement 18 illustrated in FIG. 5, omitting the separator 20.

The variant illustrated in FIG. 6 is to be compared with FIG. 3. A separator 20 is placed between the upper surface 17 of the arc 13 and the element working 18. Reinforcement frames 27 are arranged in the working element 18. The frames 27 are in the form of straight bars rigid, substantially cylindrical in diameter of the order of 10 to 30 mm. We have several frames 27 so as to follow the general shape of the working element 18 while maintaining the said reinforcement 27 drowned in the working element 18 and intersecting in the cutting plane while being shifted in depth.

Figures 7 and 8 illustrate a particular embodiment of the invention. An arch 28 covering a square-shaped piece is supported at 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 intrados 32 is formed by arches and vaults. Enter the upper surface 31 and the lower surface 32, or more precisely between the floor of the floor superior and the arches and vaults, a blockage 33, often heterogeneous, is disposed and used to fill the space and to load the vault 28. In this type of structure, there is often a deformation of the intrados 32 and a settlement of the pillar 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, no represented, can be arranged to secure the working element 34 and / or the arches or vaults of the underside 32. Tie rods 35 are attached to an upper end in the working member 34 and at one end in the pillar 29, for example at a height between the intrados 32 and the extrados 31. The tie rods 35 are distributed over all or part 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 tie rods 35 is subject to important constraints of 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 his neighborhood. The armed complex 36 comprises a plurality of rods 39 crosses comprising glass, carbon or other fibers and possessing mechanical characteristics adapted to traction. The rods 39 are arranged in substantially horizontal holes drilled from the intrados 32 at the portion 29a. The rods 39 are sealed from the same as the needles, in the portion 29a, blocking 33 and arches or vaults of the intrados 32. The armed complex 36 forms an area suitable for withstand transverse tensile forces and receive anchorage from the lower end of the tie rods 35.

For the simplicity of the drawing in Figure 8, the working element 34 and tie rods 35 have not been shown. Tie-rods 37, or tablecloths tie rods, are attached to an upper end in the walls 30 and to a bottom end in pillar 29 at the armed complex. holes are drilled in the walls 30. The upper end of the tie rods 37 is sealed on almost the entire wall thickness. are in a material similar to that of the needles and can reach sections of several square centimeters to recover efforts important. The sealing is done in the same way as for the needles. Prestressing may be applied to tie rods 37.

A wall 30 is a heterogeneous set of stones or bricks of varied dimensions and mortar. Its resistance to traction forces exerted by a tie 37 is difficult to model and, a priori, weak. To avoid the tearing of stones or bricks of said walls 30, one plans to reinforce it in the following way, prior to the laying of tie rods 37.

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

The zone in which the rods 38 are arranged is, of all ways, stabilized by the mass of the parts of walls 30 located at a level superior and exerting a compressive stress. To favor still the distribution of efforts, we can increase the number of ties 37 by decreasing their unit section and arranging them as a fan from the armed complex 36.

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

Thus, one has a method of reinforcement and a structure of masonry extending between two points of support and comprising a reinforcing element made with materials of expansion coefficients and elasticity close to those of the material constituting the structure of masonry, solidarisé with the said structure of masonry, at least a part of the 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 the said part of the masonry structure and with a fulcrum. It can thus reduce the compression load exercising on a fulcrum and postponing it on others.

A tie rod may be sealed in a fulcrum provided splitters of the tensile forces exerted by the said pulling.

Thanks to the invention, a masonry structure is obtained considerably strengthened in so far as its stiffness is proportional to the cube of the height of its working section.

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

Claims (17)

1. Process for reinforcing a masonry structure comprising at least one arch, extending between at least two distinct bearings and comprising a plurality of mutually compressed parts, each part maintaining itself by friction on the adjacent parts, in which a reinforcing element, having a synthetic resin base and made of materials with coefficients of expansion and of elasticity approximate to those of the material constituting the masonry structure and fixedly connected to the said masonry structure, is added solely on the upper surface of the masonry structure at right angles to the arch.
2. Process according to Claim 1, in which, where the masonry structure contains a vaulting, the reinforcing element is fixedly connected to the said vaulting.
3. Process according to Claim 1, in which, where the masonry structure comprises at least one arch formed of juxtaposed arch bricks, the reinforcing element is fixedly connected to the said arch.
4. Process according to Claim 3, in which a vaulting of the masonry structure is contained between the arch and the reinforcing element.
5. Process according to either of Claims 3 and 4, in which the arch bricks are supported by the reinforcing element.
6. Process according to either of Claims 3 and 4, in which the compressive stresses are distributed at least between the arch bricks and the reinforcing element.
7. Process according to Claim 6, in which the compressive stresses are distributed between the arch bricks, the vaulting of the masonry structure and the reinforcing element.
8. Process according to any one of Claims 1 to 5, in which the compressive stresses are distributed between a vaulting of the masonry structure and the reinforcing element.
9. Process according to any one of the preceding claims, in which the masonry structure and the reinforcing element are fixedly connected by means of needles sealed in holes drilled in the masonry structure and projecting into the reinforcing element.
10. Masonry structure (10) comprising at least one arch, extending between two bearings (11) and comprising a plurality of mutually compressed parts (14), each part maintaining itself by friction on the adjacent parts, characterized in that it comprises a reinforcing element (18), realized with a synthetic resin base and made with materials with coefficients of expansion and of elasticity approximate to those of the material constituting the masonry structure, disposed solely on an upper surface (17) of the masonry structure at right angles to the arch, and fixedly connected to the said masonry structure.
11. Structure according to Claim 10, characterized in that a plurality of reinforcement rods are embedded in the.reinforcing element.
12. Structure according to Claim 10 or 11, characterized in that the reinforcing element is complemented by a beam element, the reinforcing element and the beam element being fixedly connected.
13. Structure according to Claim 10 or 11, characterized in that the reinforcing element takes the form of at least one flat beam fixedly connected to at least a part of the said masonry structure, by means of ties.
14. Structure according to any one of Claims 10 to 13, characterized in that at least a part of the said masonry structure is provided with ties capable of distributing at least a part of the load towards bearings, each tie being fixedly connected to the said part of the masonry structure and to a bearing.
15. Structure according to Claim 14, characterized in that a tie is sealed in a bearing provided with distributing means for the traction forces exerted by the said tie.
16. Structure according to Claim 15, characterized in that the distributing means of a bearing are formed by at least one reinforcing bar substantially perpendicular to the tie fixedly connected to the said bearing.
17. Structure according to any one of Claims 10 to 16, characterized in that a part of the said masonry structure, subjected to transverse traction forces, is reinforced by mattresses in order to form a homogeneous traction zone.

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