Voussoirs for constructing vaults and domes

Abstract

The invention relates to a novel technique for constructing temporary or permanent vaults and domes, with a high degree of stability, without centring, using self-supporting voussoirs (1 or 3 or 4) that are inserted from the extrados. The invention can also be implemented as formwork / centring and can be used for structures that are above ground level, semi-buried or completely buried. The applications are numerous and varied, and include industrial warehouses, infrastructure (bridges, tunnels, accessible stormwater drainage systems), large shopping centres, entertainment facilities, sports facilities, etc.

Description

[0001] KEYS FOR THE CONSTRUCTION OF VAULTS AND DOMES

[0002]

[0001] The present invention relates to a new type of voussoir

[0001] as described for the easy construction of vaults and domes, stable without curvature. The structures can be temporary or permanent, completely buried or semi-buried or above ground level.

[0003]

[0002] The present invention also relates to the use of this form of key (1) as a cof f rage / bending.

[0004] [3] Since time immemorial, the arch / vault / dome form has been used. It is a super-resistant and extremely durable structure, as evidenced by the fact that some Roman buildings, among others, dating back almost 2000 years, are still in use. However, this type of construction had three major drawbacks: firstly, instability / collapse in the event of even slight displacement of the arch / vault / dome's supports; secondly, the need for curving at significant heights, which greatly complicated construction and significantly increased the cost; and thirdly, it was a very time-consuming operation. This invention solves these three major problems and offers significant stability even in the event of displacement of the vault supports (3), which can be due to various causes such as geotechnical, accidental, or seismic events, etc.

[0005]

[0004] Two prior inventions (US2067414 and US884498) are somewhat similar to the present invention in that the construction is carried out without curvature, with the blocks interlocking on the extrados. However, they exhibit excessive structural rigidity that cannot withstand significant displacement of the arch supports, which can be due to various causes such as geotechnical, accidental, or seismic events, etc. Furthermore, these structures cannot withstand significant loads, limiting these systems to very small structures of low height, with low loads, and using small blocks. Also, the newly installed blocks are embedded and supported on only one side while awaiting the arch closure, and the embedded portion is too weak, which will induce significant tensile stresses requiring substantial reinforcement with rebar.

[0006] [5] Figure 1 shows a standard voussoir (1) with its six interlocking systems (2). This interlocking system eliminates the need for bending and provides significant stability to the structure. The interlocking system can have several different forms and may even consist of several sub-interlocking systems. Form (2) is only an illustration of one possible construction. The interlocking system is characterized by an interlocking mechanism on the extrados, which allows half of the voussoir to be embedded in the initially laid voussoirs, forming an arc with a width corresponding to half the length of a voussoir (1). Figure No. 2 shows a voussoir at the base of the vault (3) with its 4 interlocking systems (2) because voussoirs at the base of the vault (3) compared to the standard form (1) must be truncated by 2 interlocking systems (2) on their lateral face in order to be laid flat.Figure 3 shows a voussoir (4) at the free end of a vault with its 5 interlocking systems (2). The 6. ème the interlocking system is truncated compared to the standard form ( 1 ) for obvious aesthetic considerations.

[0007]

[0006] Figure 4 shows a possible embodiment of the first section of the vault, corresponding to the beginning of the vault's construction. This section can be curved as in the construction of a conventional vault using a centering (6) mounted on temporary shoring (5), or it can be constructed by temporarily keying the first voussoirs together at the extrados to form one or more sections of the arch. A new voussoir is added progressively by lifting the section(s) of the arch from one side using a hydraulic excavator or a mobile crane. While awaiting the arch's closure, the sections of the arch at the base of the vault can be temporarily shored on one side or supported by cables at the base. The other sections of the arch can be shored on both sides. It will of course be necessary to subsequently unlock the keying between the voussoirs to maintain this overall stability / flexibility of the structure.It is also necessary to brace (8) the first arches of the vault to prevent a complete overturning of the structure due to the weight of the cantilevered voussoirs. To simplify the operation of placing the first arch, whose width corresponds to half the length of a voussoir (1), one can temporarily key half-voussoirs (7) with voussoirs that are not symmetrical with respect to the curvature (6). Figure No. 4 is only one example of this construction. There are several possible methods for building the first section of the vault.

[0008]

[0007] Next, the new voussoirs (1) are inserted at the extrados level into the gaps left by the last voussoirs placed, forming an arc with a width corresponding to half the length of a voussoir (1) (Figure No. 5). These voussoirs (1) are thus embedded / locked and can no longer rotate to fall; this is why curving is no longer necessary. These gaps correspond perfectly to the shape of half the voussoir. Once a section of the vault is completed (closing the arc with a width corresponding to half the length of a voussoir with the keystone), it becomes stable and load-bearing and can in turn receive the new voussoirs. In Figure No. 6, the arch feet (10) are laid first, then tie rods (11) are put in place between these arch feet (10) as shown in Figure No. 7.The intermediate voussoirs (12 and 13), only two in the case of this vault, though there could be many more, are positioned (inserted from the extrados) in Figures 8 and 9. Figure 10 shows the keystone voussoir (14), which is also inserted from the extrados. It is advisable to install either tie rods between the voussoirs at the base of the vault or backfill to resist the lateral thrusts of the arched shape. When several vaults of the same size are built side by side, these lateral thrusts self-balance in the vault bases (3), which are not located at both ends of the overall structure.

[0009]

[0007] It is possible to create floors suspended by cables from the vaults / domes or to excavate under the keystone / dome so as to increase the height under the keystone. The voussoirs (1) can be of similar, different or optimized size: feet in the shape of an elephant's foot (15) and thin at the keystone (16) as shown in Figure No. 11 or be designed to follow the different shapes of arches / vaults (pointed arch, semicircular arch, etc.) or the vault may have a surface undulating in the longitudinal direction (17) (as stipulated in Figure No. 12) or an undulation of the dome in the radial or concentric direction or following a geodetic network for the stabilization of the vault / dome. It is possible to put in place several layers of voussoirs (possibly with geotextile / geomembrane / reinforcement between these layers) to increase the overall thickness of the vault.In this case, the voussoirs in the upper layer will need to be able to be slightly modified in order to follow the shape of the lower layer.

[0010]

[0008] These vaults / domes (permanent / temporary) can be above ground level, partially buried, or completely buried. In the latter case, it is possible to backfill them with various types of materials (stabilized with polymers / copolymers / cement / binders such as soil, crushed materials, crushed construction waste, mine tailings, or industrial waste, etc., or not). This would allow for a fairly significant vault / dome thickness when using stabilized materials, capable of even withstanding a very heavy load (as in tunnels, for example).

[0011]

[0009] The voussoirs can be made, in whole or in part, from various materials such as, but not limited to, concrete in general, including reinforced, lightweight, and high / ultra-high-performance concrete, wood, plaster, plastics, brick, ceramics, metals or alloys with the mechanical and physical characteristics for such an application, stone, polymer-stabilized materials, cements or various binders, and composite materials such as engineered wood (Wood Plastic Composite), which may optionally be reinforced with nanostructured carbon. The choice of material depends on its physical characteristics, cost, availability, manufacturing process, and the application and the various stresses on the structure during construction and operation.

[0012]

[0010] This invention can also be used as formwork / bending for installing voussoirs, not necessarily following the shape of the voussoirs (1), which interlock even when small, or for manufacturing concrete vaults / elements or assembling structures made of different materials (same as

[0009] ). As shown in Figure 13, in order to be able to remove the voussoirs from the formwork / bending when the time comes, it is important that the voussoirs can be split into two halves (18) and have a temporary connecting system (19). Several temporary connecting systems can be implemented. Figure 13 shows a very simple system with a simple bar that is inserted into the slot (19) passing through the two halves of the blocks (18). The projections (20) of the interlocking system (2) can be separated from half of the key (18) and at that moment they can be fixed by bolting or any other fixing system.

[0013]

[0011] The voussoirs (1, 3, and 4) can be cast in formwork, including lost formwork, 3D printed, or manufactured or prefabricated in part or in whole. These voussoirs (1, 3, and 4) can also have a dual structural and aesthetic function, offering not only structural strength but also an aesthetic function (e.g., decorative patterns or special finishes). This can include specific voussoir shapes to create unique visual effects inside or outside the vaults. The voussoirs (1, 3, and 4) can also have integrated mechanical reinforcements or multiple layers of voussoirs, including layers corrugated in the longitudinal direction (17).

[0014]

[0012] Joint covers such as expansion joints can be put in place to prevent water from passing between the voussoirs.

[0015]

[0013] This invention can be used for the design of new compact cities where a large part of the major structures can be underground and even very close together. The potential applications of this technology are numerous, but not limited to: bridges, tunnels, subways, transport in general, stormwater drainage, hangars (factories, depots, cold storage facilities, markets, supermarkets, underground structures, etc.), storage (energy with molten salts for example, water, hydrocarbons, raw materials, etc.), parking lots, hydroponic crops (supported by cabling), various activities (tourism, commercial, productive including animal and plant production, leisure, social, educational, professional, cultural, restaurant, sporting, religious, medical, residential or office use, etc.).

Claims

AMENDED CLAIMS received by the International Bureau on June 29, 2026 (29.06.2026) Claim 1.A vault construction device comprising voussoirs (1, 3, 4) with curved or polygonal surfaces, the extrados face of which has a larger surface area than the intrados face, characterized in that the voussoirs are assembled by means of an interlocking system (2) whereby each voussoir is inserted from the extrados onto two previously placed adjoining voussoirs forming an arch in progress, a length corresponding to half the dimension of the voussoir, measured along the direction of progression of the arch, being fixed onto said two adjoining voussoirs while the remaining length remains cantilevered until the placement of the next voussoir, the interlocking system (2) giving the vault a high degree of freedom allowing it to maintain its stability even in the event of relative displacement of the vault supports (3), the construction continuing without centering or temporary support after the establishment of a first initial arc. Claim 2. Device according to claim 1, wherein the interlocking system (2) consists of several complementary interlocking subsystems acting jointly. Claim 3. Device according to claim 1 or 2, wherein each key (1) comprises two interlocking means (2) on each of the two opposite faces oriented along the direction of progression of the arc. Claim 4. A device according to any one of claims 1 to 3, wherein the voussoirs (1) have a variable thickness, thicker at the foot of the vault (15) and thinner at the keystone (16), in order to optimize the quantity of material. Claim 5. A device according to any one of claims 1 to 4, wherein the vault has an undulation in the longitudinal direction (17). Claim 6. Device according to any one of claims 1 to 5, wherein each voussoir (1) is split into two halves (18) connected by a temporary connecting system (19) allowing the voussoirs used as formwork or bending to be removed. Claim 7. Device according to any one of claims 1 to 5, wherein the voussoirs (1) are cast in forms including lost, 3D printed, or manufactured or prefabricated in part or totally. Claim 8. Device according to any one of claims 1 to 5 and 7, wherein the voussoirs (1) provide a dual structural and aesthetic function, in particular by means of decorative motifs, special finishes or voussoir shapes producing visual effects on the interior or exterior of the vault. Claim 9. Device according to any one of claims 1 to 5 and 7 to 8, wherein the voussoirs (1) have integrated mechanical reinforcements or several layers of voussoirs, including layers corrugated in the longitudinal direction (17). Claim 10. Device according to any one of claims 1 to 5 and 7 to 9, wherein a joint cover, of the type of expansion joint covers, is put in place to prevent water from passing between the voussoirs (1).

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