EP0001367A1 - Antiseismic buildings with basements forming an atombomb-proofed shelter - Google Patents

Abstract

The present invention relates to earthquake-resistant constructions, in particular constructions with basements forming atomic shelters. In this type of construction, the underground base of the construction is constituted by a plurality of independent elements (3, 10) having a mechanical resistance such that each of them is capable of withstanding without damage to the seismic wave of maximum intensity. These constructions are used as atomic shelters.

Description

The present invention relates to the construction of buildings liable to be subjected to earthquakes of natural origin or caused by atomic explosions.

It is generally known to reinforce the cellars of existing buildings to transform them into shelters against shells and explosive bombs of the conventional type. In this case, the shelter must be able to withstand the puncturing power of the device and the shaking of the ground caused by the explosions. However, these are phenomena corresponding to a fairly low energy released and, except in the case of blows falling directly on the shelter or in its very immediate vicinity, disturbances that may occur in the structure of the shelter such as cracks , do not endanger the lives of the occupants.

It is quite different in the case of atomic shelters because nuclear weapons with incomparably greater power act at distances from the point of impact corresponding to several kilometers by several phenomena which it is necessary to protect the users of the shelter . These phenomena are a wave atmospheric overpressure which results in a violent blast of the cyclone type, a seismic pressure wave, radiation of the pure calorific and radioactive type and radioactive fallout. It is also necessary to protect users against derivative phenomena, in particular fires ignited by heat radiation, projectiles, rubble and dust resulting from the atmospheric overpressure wave, gaseous fumes resulting from destruction of distribution networks, or even gases. or biological agents used to infect the bombed area and finally possible floods.

In fact, therefore, the shelter must have a mechanical resistance far superior to conventional shelters in order to be able to resist in particular the seismic pressure wave, any cracking removing the seal necessary to cope with pollution and the dangers resulting from radioactive fallout. , gases and thermal effects and also water.

It is difficult to envisage an atomic shelter in superstructure because it must then resist by itself and in all its parts to the wave of atmospheric overpressure, it must be very monolithic which makes its construction expensive and in addition its architectural aspect is unsightly. It can be buried outside any construction but, on the one hand, it is often difficult to find a site of establishment, on the other hand, it must be occupied almost permanently because of its forced distance from the premises of housing and workplaces and, finally, buildings constructed in superstructure on the shelter form, especially when they are, in reinforced concrete, primary screens against conventional bombs and shells. However, they create a risk collapse on the shelter and fire that may develop above it.

It is therefore essential that the buried atomic shelter perfectly withstand the seismic pressure waves generated by the bomb. Depending on the distance from the point of impact, the determining phenomenon for the collapse of the superstructures can be the atmospheric overpressure wave, or the seismic wave acting on the foundations which shakes the entire structure. In the case of an earthquake, it is the seismic wave that causes the buildings to shake and collapse.

The aim of the present invention is to produce constructions in which the buried part can withstand intense seismic tremors, whether of natural or atomic origin, without risk of serious degradation, the horizontal displacements to which the buried part may be subjected. of construction, not being transmitted to the superstructure.

This object is achieved in accordance with the invention by the fact that the buried base of the construction is constituted by a plurality of independent elements having a mechanical resistance such that each of them is capable of withstanding without damage to the seismic wave of maximum intensity and to support a large fraction preferably greater than a third of the weight of the superstructure, the superstructure being calculated to resist in the case of an isostatic bearing on three points distributed randomly among its points of support provided for construction on the base elements, the shear strength of the connections to the support points of the super structure on the base elements being less than the overall shear strength of the elements of the structure leading to the point considered.

With this embodiment, the elements of the base can, under the effect of seismic waves, undergo relative displacements without any effort, in particular of shearing, greater than the mechanical resistance of the superstructure, being transmitted to the latter.

A dislocation of the base into its independent elements can result in a support of the superstructure on only three of these elements providing isostatic support but without dislocation of the superstructure, which protects the occupants from the risk of collapse and allows a resumption in subsequent underpinning, for example by injection, to level the base again.

Preferably and in accordance with another characteristic of the invention, the independent elements of the base are constituted, at least in part, by habitable cells forming atomic shelters.

According to another characteristic, the independent elements are spaced from each other by a distance at least equal to the compressibility of a ground thickness equal and parallel to their greatest horizontal dimension under the maximum pressure developed by the seismic wave d 'maximum intensity.

The gap between two independent elements is, in particular in the case of habitable cells, closed by a compressible material as impervious as possible to water, gases and radiation. This material distorted ble may be a heavy metal filled foam or a composite material based on foam and malleable metal layers.

According to another characteristic, the elements of the base are separated from the elements of vertical walls delimiting the excavation of the base, the gap being filled with a tight compressible material.

It is customary to provide access to the atomic shelters with airlocks and such airlocks will eventually be provided to give access to the cells or to the group of cells. However, normal inputs located under the superstructure may be obstructed by collapse of the superstructure under the effect of the atmospheric overpressure wave. To remedy this, it has already been proposed, for example in French patent No. 1,375,468 of November 22, 1963, to provide air-raid shelters with an emergency exit constituted by an underground hose connecting said shelter to a well dug in the ground . It is known that this outlet well must be located at a distance from the building at least equal to the height of the latter and the above patent proposes to provide at the entrance and at various points of the hose doors of isolation. It is however certain that such a hose subjected to an intense seismic shock is likely to collapse and that metal doors are likely to jam. In the context of the development of the present invention, the emergency exit is carried out by tubular elements which can individually resist without crushing the earthquake of maximum intensity, the various elements being joined together by flexible joints capable of absorbing the relative displacements of two successive elements. According to one embodiment, the ends of two tubular elements successive, spaced apart by a sufficient distance to absorb the relative displacement, are engaged in a tubular junction element having the same mechanical resistance characteristics but reserving between its internal surface and the external peripheral surface of the internal elements a clearance greater than the relative displacement, this clearance being filled with a deformable material similar to that used between the base elements.

According to another characteristic, access to the emergency exit is closed off by a rigid destructible wall with the tools located in the shelter, for example a masonry wall, unreinforced concrete or other similar material.

• La figure 1 est une vue en coupe verticale schématique d'un immeuble conforme à l'invention;
• La figure 2 est une vue de détail d'une partie de la cellule reliée à la sortie de secours.

The present invention will be described in more detail below in the form of an exemplary embodiment with reference to the attached drawings in which:

• Figure 1 is a schematic vertical sectional view of a building according to the invention;
• Figure 2 is a detail view of part of the cell connected to the emergency exit.

The invention, in the embodiment shown in the drawings, is applied to a two-story building. The buried basement is on one floor and has a part 1 forming garages and a part 2 forming an atomic shelter. Part 1 comprises a certain number of slabs 3, reinforced concrete slabs having a thickness and a sufficient reinforcement to be able to support each a significant fraction which can theoretically reach a third of the total weight of the construction, concentrated in their center. To increase their resistance, these slabs can be profiled and include beams forming a crossed network. The building is supported on the slabs 3 by posts 4 provided with a distribution sole 5. The distribution sole 5 is not secured to the slab 3, except possibly by irons of small section capable of being sheared in the event of a shear force exceeding the shear strength of the post 4. In the case of a construction in a particularly exposed area or a construction of a particular nature whose destruction could constitute a serious danger, for example power stations nuclear, a vertical elastic connection can be provided between each slab 3 and each post 4. An optimal solution would be a construction of the completely isostatic type in which each support between the building and the base comprises, as shown in Figure 2, a cylinder 6 interposed with a ball joint system between each sole 5 and each post 4 or between a metal distribution sole 5 'bearing on a habitable cell 10 forming atomic shelter as described below and a support plate 7 incorporated in the system of load-bearing beams 8 of the building in superstructure. The jacks 6 are divided into three groups and the jacks of the same group are interconnected by pipes 9. Each jack or group of jacks can be connected to an enclosure for absorbing pressure waves in the form of a hydropneumatic chamber or analog not shown. With this embodiment, a vertical wave which propagates under the elements with a vertical amplitude less than the stroke of the cylinders, can be absorbed without damaging the construction.

Part 2 is made up of habitable cells also made of reinforced concrete 10. These cells are calculated individually to be able, like the slabs 3, to support a large fraction of the weight of the construction and to be able to resist crushing by seismic waves acting on their lateral faces. It should be noted that when distributor actuator systems 6 are provided, the weight of the construction is always distributed between the various supports and the fraction of the weight of the building that each support must support is therefore lower. These cells are equipped, like all conventional atomic shelters, with standard emergency equipment with regard to means of survival, ventilation, lighting and disinfection. They can be used directly as support, without mechanical connection preventing a horizontal displacement or limiting it beyond a certain shearing force, to the superstructure construction. This support can also include a hydrostatic connection device as shown in FIG. 2.

In general and in accordance with the invention, the base elements, slabs 3 and cells 10, are separated by a distance approximately equal to the maximum amplitude of the displacement which can receive the element under the effect of a natural or atomic earthquake. The gap thus created is filled by a seal 11 made of an elastically deformable waterproof material which can be a plastic foam loaded with heavy metal salts. This joint can, as shown in Figure 2, be delimited or subdivided by lead walls or the like 12 which can be folded and anchored in neighboring elements. The plastic foam of the joint, which must have as high elongation and compression coefficients, is preferably cast on site and it is possible to provide cavities in the surfaces of the adjacent parts. anchor for the foam (not shown) so that, even when stretched, the foam continues to seal.

To reduce as much as possible the transmission of seismic waves to the elements of the base, the side walls of the cells 10 directed towards the ground, can be doubled by walls 13 which are separated from it by a thickness of foam 14 treated like the foam of the joints 11 The side walls 15 of the other basements are preferably mounted also floating with seals 11 at the base and at the top. The watertightness, gas and radiation tightness of the seals not incorporated in part 2 forming an atomic shelter, can be neglected and they may be simple overlapping seals liable to shear under the stresses resulting from 'an earthquake.

The superstructure construction 16 is constituted as a self-supporting element, especially when the load is transferred directly, that is to say without connection of the type of jacks 6, to the elements 3 and 10 of the base. To do this, truss-forming reinforcements 17 are embedded in the partitioning walls made of sheet concrete arranged in two orthogonal orientations. Architectural elements such as thresholds 18, pediments 19, balconies 20 and others are calculated as belt elements and reinforced accordingly. To increase the moment of inertia and the resistance to fracture along a median plane, beams such as 21 in which a part of the truss reinforcement is embedded can be arranged in a grid on the terrace.

Those of cells 10 which are in the vicinity of the land, may include emergency exits leading by a buried hose 22 to an outlet well 23 disposed at a distance from the building 16 substantially equal to its height to prevent its outlet from being blocked by the collapsed parts. In the embodiment, this outlet is surrounded by a concrete ring 24 forming a barrier against runoff water. The hose 22 consists of elements such as centrifugal reinforced concrete pipes 25 capable of resisting the seismic wave. The connections between elements are constituted by foam rings 26 having thicknesses sufficient to absorb the relative displacements. These rings are held in place by metal hoops 27. Access to the hose 22 can be achieved by destruction, using the tools located in the shelter, of a thinned part 28 of the facing wall. -vis cell 10, the frames 29 also being interrupted to the right of this thinned part.

The embodiments described above are capable of receiving numerous modifications without departing from the scope of the present invention.

Claims (11)

1. Anti-seismic construction, in particular construction with basements forming atomic shelters,
characterized in that the buried base of the construction is constituted by a plurality of independent elements having a mechanical resistance such that each of them is capable of withstanding without damage the seismic wave of maximum intensity. 2. Anti-seismic construction according to claim 1,
characterized in that the shear strength of the connections at the points of support of the superstructure on the base elements is less than the overall shear resistance of the elements of the structure leading to the point considered. 3. Anti-seismic construction according to any one of claims 1 and 2,
characterized in that the independent elements of the base consist, at least in part, of habitable cells forming atomic shelters. 4. Anti-seismic construction according to any one of claims 1 to 3,
characterized in that the independent elements are spaced from each other by a distance at least equal to the compressibility of a thickness of ground equal and parallel to their greatest horizontal dimension under the maximum pressure developed by the seismic wave of maximum intensity. 5. Anti-seismic construction according to claim.4,
characterized in that the interval between two independent elements is, in particular in the case of habitable cells, closed with a compressible material as impervious to water, gas and radiation. 6. Anti-seismic construction according to any one of claims 1 to 5,
characterized in that the base elements are spaced from the vertical wall elements delimiting the excavation of the base, the gap being filled with a compressible waterproof material. 7. Anti-seismic construction according to any one of claims 1 to 6,
characterized in that the emergency exit constituted by a buried hose leaving the habitable cells is formed by tubular elements which can individually resist without crushing the earthquake of maximum intensity, the various elements being joined together by flexible seals which can absorb the relative displacements of two successive elements. 8. Anti-seismic construction according to claim 7,
characterized in that the ends of two successive tubular elements, spaced apart by a distance sufficient to absorb the relative displacement, are engaged in a tubular junction element having the same characteristics of mechanical resistance but reserving between its internal surface and the external peripheral surface interior elements play greater than the relative displacement, this play being filled with a deformable material. 9. Anti-seismic construction according to any one of claims 7 and 8,
characterized in that the access to the emergency exit is closed by a rigid destructible wall with the tools being in the shelter for example a wall in masonry, in non-reinforced concrete or other similar material. 10. Anti-seismic construction according to any one of claims 1 to 9,
characterized in that the superstructure construction is supported on the base elements by means of jacks distributed in three groups, the jacks of the same group being interconnected. 11. Anti-seismic construction according to any one of claims 1 to 9,
characterized in that the superstructure is calculated to resist in the case of an isostatic support on three points distributed randomly among its support points provided for construction on the base elements.

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