FR2492866A1 - Building foundations resistant to vertical earthquake tremors - incorporating components of rubber and PTFE - Google Patents

Abstract

In designs for foundation supports to protect buildings from vertical as well as horizontal vibrations from earthquake tremors etc., the building stands on platforms connected by resilient supports to lower platforms fixed to the ground by a combination of elastic supports and dashpots. The elastic supports include pillars of 'neoprene' (polychloroprene) rubber. PTFE is used for low friction pads to allow horizontal shifts between metal caps on rubber pillars and steel plates under the platforms which may be supported by the pillars. PTFE coatings are used to line openings in metal plates through which some of the rubber pillars pass. PTFE hoops are also used to reduce friction between concentric caps on rubber pillars used to damp torsional movements. Designed to cope with vertical accelerations greater than 1g. No specific dimensions or rubber characteristics quoted.

Description

 The subject of the invention is a structure for the protection of a construction against oscillations liable to destroy it as a result of a large earthquake, an explosion, etc. This structure uses the principles that are already described in US Patent No. 4,166,344 to the applicant. The present invention provides an improvement by the addition of a mechanism which protects the construction against vertical oscillations in addition to the protection against horizontal oscillations, which provides a three-dimensional insulating structure.

 The oscillation that a point of the earth can undergo, as a result of a seismic shock, occurs in three dimensions and is different at each earthquake. In other words, this oscillation is expressed in a three-dimensional coordinate system OXYZ comprising three components, that is to say: the oscillation consists of three components along the three axes OX, OY and OZ. Assuming that the OZ axis is vertically arranged, the oscillation component of a tremor along this axis is called the vertical component and the components along the OX and OY axes are called the horizontal components. The seismographs, that is to say the devices that record the movements of the earth, record these three components. However, the relative importance of the components is not the same when it comes to building safety. It has been generally accepted that the vertical component is usually less important than the horizontal components because the capacity of the structure to transfer vertical loads is generally much greater than for horizontal loads. This is because the structures are designed in a way that is suitable for the transfer of vertical loads and that the soil capacity is generally much larger to contain the vertical forces than the horizontal forces. Moreover, it has been assumed that the possibility of observing a vertical component OZ of seismic accelerations greater than 1 g is very small because it has been assumed that the soil and the surface which carries the structure are not generally capable of transferring tension forces.

From these data, the construction technique for earthquake protection focused mainly on horizontal components and gave only minor consideration to vertical components. However, during an earthquake that occurred in Imperial Valley, California,
USA, in 1979, an accelerometer (station 6) recorded a vertical component of 1.74 g. The reason for this fact is not yet fully understood. However, this particular station was located at a distance of a few kilometers from the fault and, in fact, was between two faults that were disturbed during the earthquake. It is possible that the earth was squeezed horizontally at this point by simultaneous disturbances along the two faults, which would have caused a great vertical acceleration. In any case, this event has made it clear that the vertical components of earthquakes need more attention and that the isolation of structures from all components, both horizontal and vertical, is desirable, at least in some cases. The cases in which this isolation may be necessary will be better known when it becomes clearer what are the conditions which give rise to vertical accelerations of significant magnitude.

 In Applicant's US Pat. No. 4,166,134 there has been described an insulating structure with respect to ground motions when horizontal seismic accelerations exceed a predetermined value. This system comprises a disc, usually made of reinforced concrete, supports that bear the weight or vertical load of the structure and which also impose on the structure elastic restitution forces that react against horizontal movements, connecting means that prevent movement horizontal of the structure in normal circumstances, for example when the building is subject to the force of the wind. The connecting means are designed to unhook when the structure is subjected to horizontal forces greater than a predetermined value.

 Until we invent new building materials, whose properties would be suitably different from the properties of existing materials, something that can not be predicted. it is also absolutely necessary to avoid certain structural elements in order to eliminate the instability of the structure. The elements to be avoided are those which transfer the large axial loads in a first direction and which are simultaneously solicited to follow large deformations in a second direction which is perpendicular to the first. For this reason, it is necessary to provide separation elements to achieve vertical and horizontal insulation.

 The main object of the invention is to provide support for insulating structures both horizontally and vertically. In particular, the invention provides a vertical isolation means in combination with the horizontal insulation means disclosed in US Patent No. 4,166,134. However, the vertical insulation means which is part of the present invention may also be used. regardless of the vertical insulation means or, on the contrary, at the same time as other horizontal insulation means. An important feature of the invention is the separation of the elements which provides the isolation of the vertical direction and the horizontal direction.Thus, unlike the structure described in the aforementioned patent where there is a single disc of protection against ground movements, now two discs are planned. Between these disks, which are placed one above the other, there are isolation means and additional insulation means are arranged between the lower disk and the foundation. One isolation means isolates the vertical forces and the other isolates the horizontal forces. This separation of the isolation means is important if one wants to avoid the instability of the constituent elements and the entire structure.

For the sake of convenience, the ground motion protection system described in US Pat. No. 4,166,134, which has been known hitherto as Alexisismo, will be referred to herein as Alexisismo No. 1 so that distinguishes it well from the three-dimensional isolation means of the present invention. The vertical isolation means of the present invention will be called
Alexisismo No. 2. The structure according to the invention which will be described later contains both Alexisismo No. 1 and
Alexisismo nO 2. However, as we said before,
Alexisismo nO 2 can be used independently or with other means of horizontal insulation.

Alexisismo nO 1 can be characterized by the following elements that it includes
a) supportsAlexisismo nO 1 (AS1)
b) Alexisismo connection means n0 1 (AC1)
c) one or more Alexisismo discs nO 1 (AD1).

In order to provide insulation in all three dimensions, the present invention comprises three additional elements that can be designated as follows
a) Alexisismo supports nO 2 (AS2)
b) Alexisismo nO 2 liaison means (AC2)
c) one or more Alexisismo discs nO 2 (AD2).

 It should be understood that under certain circumstances the axes of the coordinates OX and OY and the axis OZ may not be horizontal and vertical respectively but that they are in all cases perpendicular to each other. However, for simplicity, we will use the words "vertical" and "horizontal." The same principles can be applied to the structures for which the reactions of the supports are inclined with respect to the vertical.

 The AS1 support (s) are the same as those of the Alexisismo # 1 structure which are described in the patent already mentioned. We can refer to the latter whose description is included by reference to this application.

 The means AS2 comprises the structural elements which transfer the vertical loads of the superstructure to the foundation and which are arranged between AD2 and the foundation (the ground) or between AD1 and AD2. The location and number of supporting elements that collectively constitute AS2 are left to the discretion of the designer of the structure.

However, it is preferred that these elements be arranged at the points of concentration of the vertical loads, ie below the columns. The elements that make up AS2 must be able to safely transfer the vertical loads of the structure. They must have sufficient flexibility in the vertical direction to ensure a period of vertical oscillation of the structure that is sufficiently wide to adequately isolate the structure of vertical seismic ground motions.

As will be apparent from the description given below, means are provided to prevent the imposition of significant eccentricity on AS2. These means comprise elements which limit the relative horizontal movements between the members united by AS2, that is to say between
AD2 and the foundation or between AD2 and AD1; these means do not restrict the relative vertical movements between the organs united by AS2. This characteristic gives the assurance that
AS2 is not subject to horizontal deformations that could make the structure unstable. The elements that provide this protection may be vertical columns extending upward from the foundation and comprising
AD2 or columns extending vertically from AD1 and including AD2. Other arrangements will be readily apparent by themselves. Of course, these columns, or similar elements, should allow small movements that are due to thermal expansion and contraction. In addition, these elements must be strong enough to withstand the horizontal forces that are established in the isolated structure during an earthquake. Depending on their design, these elements can also prevent rotations between AD2 and the foundation or between AD1 and AD2 or can allow rotations, in accordance with the requirements of the structure.

Similarly, means can be provided to substantially prevent vertical displacements between the elements united by AS1.

The exact design of AS2 results from the evaluation of the expected behavior of the entire structure during an earthquake based on the principles of dynamic structure analysis. AS2 must be very flexible and elastic in the vertical direction. Consequently, the displacements of the superstructure with respect to the ground, as a result of the vertical oscillations, can be great and may not be acceptable during the normal duration of the structure, that is to say outside of the great earthquakes . Therefore, the installation of AC2 may be required to prevent these movements during periods other than those of a large earthquake. However, in the case where these movements are acceptable in normal times,
AC2 can be omitted.

 The connecting means AC1 is of the same type as the Alexisismo nO 1 connecting means and will not be described in detail here. Reference is made to the description of the patent already mentioned above.

AC2 comprises structural elements which are arranged between the same elements as AS2, that is to say between AD2 and AD1 or between AD2 and the foundation. The elements of AC2 are designed to provide resistance to relative vertical movements between AD1 and AD2 or between AD2 and the foundation, in proportion to the speed of these movements. As a result, AC2 offers little or no resistance to slow movements but provides substantial resistance against fast movements. In the example shown and described here,
AC2 comprises a cylinder containing a piston and a fluid (usually liquid) so that the piston divides the cylinder into two vertically spaced chambers. The piston is joined by a rod, for example to AD2, and the cylinder is joined for example to the foundation. There is a small tube around the cylinder or an opening through the piston to allow the transfer of a small amount of liquid only. As a result, in the case of rapid movements, due to the limited flow of fluid through the tube or opening; the fluid opposes a resistance. On the contrary, in the case of slow movements, the fluid offers almost no resistance.

Detachment or disconnection elements are provided so that the fluid members are functional only during normal circumstances. Thus, for example, the connection between the cylinder and the foundation may include a rod that breaks when subjected to a predetermined magnitude of force. The arrangement is such that during slow movements the cylinder containing the fluid provides only a slight resistance, so that a small force, if any, is exerted on the rupture element. On the contrary, when rapid vertical movements occur, for example during an earthquake, the fluid offers resistance and a stress is imposed on the rupture element. When this stress becomes greater than the resistance of this element, for example in the case of a large earthquake, it breaks and the connection with AC2 is removed. The only link that remains between AD1 and AD2 or between AD2 and the foundation, after the breakage of these elements, is through AS2. The flexibility of AS2 allows vertical oscillation and, if desired, rotation at an appropriate period, so that the structure is not damaged. Degrees may be provided to limit vertical oscillations to predetermined displacements which prevent damage to
AS2 when the structure is likely to undergo vertical oscillations that would otherwise damage AS2.

 The number and location of the elements of AC2 are determined at will by the designer of the structure.

AC2 is arranged to substantially pocket any rapid vertical relative motion between the superstructure and the foundation under the effect of wind and small earthquakes. These elements allow slow vertical movements and are disconnected in case of strong earthquakes.

 AD2 disks are similar to AD1 disks and, typically, are made of reinforced concrete or steel. Their strength and structure are left to the discretion of the designer.

We will now give a detailed description of several embodiments of a structure according to the invention. Reference is made to the accompanying drawings in which
FIG. 1 is a schematic sectional view through a vertical plane of an embodiment of the invention.
- Figure 2 is a sectional view through a horizontal plane according to 2-2 of FIG. 1
FIG. 3 is a sectional view along a longitudinal plane of a support pot used as a component of a kind of AS1, useful for the invention,
FIG. 4 is a sectional view of a kind of AS2
- Figure 5 is a sectional view of another kind of
AS2
FIG. 6 is a sectional view of a preferred embodiment of AC2
FIG. 7 is a schematic sectional view through a vertical plane of another embodiment of the invention,
FIG. 8 is an elevational view, partly in section, showing a constituent part of AS1
FIG. 9 illustrates another embodiment of AS1
FIG. 10 is a view from above of AD2 illustrating another embodiment of columns which limit the relative horizontal movement and the rotations between AD2 and
AD1 or the foundation
FIG. 11 is a sectional view along 11-11 of FIG.
Figure 12 is an enlarged view in elevation; partially in section, of an embodiment of AS1 similar to that of FIG.
FIGS. 13 and 14 are respectively perspective views of another embodiment of AS2
- Figure 15 is a sectional view through a vertical plane of another embodiment of the structure of the invention.

 FIG. 1 illustrates a structure which comprises a superstructure 1 of which columns 2 are part. These are supported by a concrete platform or by a metal platform 3 which includes Alexisismo discs nO 1. structure there is a horizontal platform 4 made of reinforced concrete or metal which constitutes a disc Alexisismo nO 2, and under the platform 4 there is a foundation 5. To limit the horizontal movement of the platform 4 ( AD 2), the foundation is provided with columns 6 extending upwards, which are spaced from this platform 4 by a slight clearance to allow expansion.

The same columns 6 can be used as stops in the vertical direction to limit the possible vertical movement between AD2 and the foundation. Similarly a stop 106 is provided to limit the vertical movements between AD1 and AD2. This abutment consists of a vertical pillar 206 with a head 207 extending vertically from the top. The pillar 206 extends from AD2 through an opening 208 provided in AD1. This opening 208 must be large enough to allow the horizontal oscillations envisaged during an earthquake. A plastic layer 209, for example polytetrafluoroethylene, may be placed between the abutment head 207 and AD1.

 Between the platforms 3 and 4 (AD1 and AD2) are the components components of Alexisismo nO 1, namely AS1 and AC1. They are represented in schematic form only. In particular, AS1 comprises, for example, support pots 7 which are provided with a frictionless sliding surface, for example polytetrafluoroethylene, which slide on a stainless steel surface and rubber columns 8. A suitable support pot is shown in Fig. 3. A suitable type of rubber column is shown in Fig. 8 and will be described later. AC1, schematically illustrated and designated 9, may be of the type described in the application. U.S. Patent No. 4,6,760 filed June 8, 1979; reference can be made to the description given in this application which is included by reference to this description.

 As shown in Figure 3, the carrier member 7 may be a support pot comprising a base 11 of steel and a cylinder 12 which extends upwardly therefrom. Inside the cylinder is disposed a mass 13 of neoprene. A closure ring 14 and a piston 15, placed on the neoprene mass, close the chamber that contains the latter. The piston 15 has at its top a lateral flange 16 which extends laterally and which projects beyond the cylinder 12 but which is spaced vertically from the latter by a clearance b. This game allows a limited rotation.

The upper face of the piston 16 has a recess which contains a pad 17 of polytetrafluoroethylene; it extends above the upper face of the piston. On this buffer 17 rests with a sliding possibility a plate 18 of stainless steel. The latter must be sufficiently larger than the polytetrafluoroethylene buffer to allow any intended horizontal movement. These displacements can be rather important.

The plate 18 of stainless steel is welded to a steel plate 19 which is, in turn, bolted or otherwise fixed to the concrete covering it.

 Another embodiment of a support pot specially adapted to the basic insulation structure Alexisismo No. 1 is illustrated in Figure 9. For convenience, the parts that correspond to the example of Figure 3 are designated by the same reference with the premium index. Thus, the disc 13 'of elastomer is enclosed in a cylinder 12' below a piston 15 '. Above this is the polytetrafluoroethylene buffer 17 ', the stainless steel disk 18' and the steel plate 19 '.

Below the disk 13 'of elastomer is a metal plate 40, of the same surface, disposed inside the cylinder, and a ring 41 welded inside the cylinder 12' or integral with it, so when it occupies its lowest position, the plate 40 is supported by the ring 41. In the case of vertical oscillations which increase the distance between a part of AD1 and the ground under this part of the structure, the pot of Supporting Figure 9 provides the means to ensure the integrity of support; there exists inside the ring 41 a compression spring 42 which raises the plate 40. This spring 42 does not support the weight of the structure but it raises the elastomeric disk when the distance between AD1 and the ground increases by As a result, the spring ensures that the parts 17 'and 18' will not separate one from the other.

Figure 8 shows another constituent part of AS1 that can be used with the support pot of FIG. 3. It is a cylindrical column 8 rubber anchored at its base AD2 (or foundation). A hole 108 is formed through AD1 to a size large enough to pass the rubber column; this hole can be lined with a steel tube. During horizontal movements between
AD1 and AD2, or between AD1 and the foundation, the upper part of the rubber column 8 is displaced in the lateral direction and it applies to the structure horizontal forces of repositioning whose magnitude increases with displacement. The dimensions of the columns 8 depend on the characteristics of the rubber used. These can be determined by evaluating the intended behavior of the overall structure during an earthquake, using the principles of dynamic structure analysis.

 A more evolved design of the rubber column 8 is illustrated in FIG. 12. On the left side of the latter, a column 43 can be seen at its normal position and, on the right side, a column 43 'which is located in the state where it is set when AD1 has been moved laterally with respect to AD2. In each case the column comprises a vertical rubber cylinder 44 and a steel cylinder 45 extending vertically from the top of the rubber cylinder. The two cylinders are joined to each other at 46.

 A steel tube 47 is embedded vertically in the disk AD1, with its lower end open to receive the steel cylinder 45 the tube 47 has an inner diameter greater than that of the cylinder 45.

The steel tube 47 and the steel cylinder 45 must be of sufficient length so that the cylinder is not pulled out of the tube when AD1 is moved horizontally with respect to AD2. The necessary length can be calculated by any engineer who knows the maximum horizontal displacements for which the structure is designed.

As shown in Fig. 12, two rings of friction reducing material, such as polytetrafluoroethylene, surround the steel cylinder 45 and are spaced from each other vertically. The upper ring 147 is joined to the steel cylinder 45 and the lower ring 247 is joined to the steel tube 47. In both cases. the ring has a thick
less than the space between the cylinder 45 and the tube 47.

 AS2 may comprise a cylindrical rubber column, as shown in FIG. 4, which allows substantial vertical movements or a steel spring, shown in FIG. 5, or bearing blocks composed of alternating rubber and steel plates; etc. The modulus of elasticity, the dimensions and the profile of AS2 are chosen to give a sufficiently high fundamental period to the vertical oscillation of the structure. These values can be calculated according to the principles of dynamic analysis.

 Figures 13 and 14 illustrate a different embodiment of AS2. Figure 13 shows a rubber column and Figure 14 shows how this column is enclosed in a tube. As seen in FIG. 13, there is a steel pillar 55 extending downward from AD2 and a rubber column 56 having the same cross-section as the pillar and extending downward from this one until the foundation or until AD1, in 57-. The rubber column can be joined to the pillar.

The rubber column is divided into four portions 58, 59, 60 and 61 which are separated by plates 62, 63 and 64.

The parts of the rubber column are joined to these plates. For convenience, two flat plates can be used together, as shown in the figure, to make replacement of a portion of the rubber column easier. The assembly is enclosed, in its entirety, inside a tube 65 of the same profile as the plates 62, 63 and 64, with the steel pillar 55 extending upwards to AD2 above from the top 66 of the tube. There must be a sufficient distance between this vertex 66 and AD2 so that they do not come into contact during the envisaged vertical oscillations of the structure. There is clearance between the rubber column and the inside of the tube 65 but the plates 62, 63 and 64 slide against the inner surface of the tube 65. Accordingly, the tube 65 limits the buckling of the rubber column. The plates 62, 63 and 64 increase to a certain extent the rigidity of the latter but also help to limit buckling.

 A preferred embodiment of AC2 is visible in Figure 6. Its constitution is similar in part to a conventional shock absorber and comprises a cylinder 20 filled with fluid containing a piston 22. The latter is provided with a piston rod 22 which extends upwardly through an opening 23 formed in the upper wall of the cylinder and which is joined to the concrete platform above it. A small diameter tube 24 extends vertically along the cylinder 20 and is connected at its upper and lower ends 26 to the upper and lower end portions of the cylinder 20. Thus, as the piston moves up or bottom, fluid is forced through the tube 24.

During slow movements, such as the descent of the disks during construction or because of the settling of AS2 or slow vertical movements caused by a weak seismic shock, the tube provides little or no resistance to the flow of liquid, so that AC2 opposes little or no resistance to vertical movements.

On the contrary, the tube opposes a substantial resistance to the rapid flow of the liquid, so that AC2 opposes a substantial resistance to the vertical movements that occur during a strong earthquake.

 The piston 21 has from its underside a vertical blind recess 27 in which a rod 28 extends from the bottom of the cylinder 20 with a possibility of sliding in association with a suitable seal. The rod 28 serves to equalize the volume of the fluid due to the movement of the piston rod during the movements of the latter. Other known equalization mechanisms can be used.

 A breaker designated by the general reference 29 is disposed under the cylinder 20 to join AC2 to the foundation or disk. This element comprises two pillars 30 and 31 which support a rupture bar 32.

This extends with a possibility of sliding through a hole 33 which passes through the lower part of the cylinder 20. Notches 34 and 35 are cut in the bar 32 which breaks when a force of predetermined magnitude is applied thereto. Such a force is exerted on the bar when rapid vertical oscillations are imposed on the structure and the fluid in the cylinder 20 opposes a substantial resistance. The force required to break the bar 32 can be calculated from the knowledge that one has vertical forces that the designer intends to support the superstructure without substantial vertical oscillation relative to the ground. After an earthquake, we can replace the bar 32.

 Instead of the columns 6 which limit the horizontal displacement but which allow a rotation between the parts joined by AS2, one can employ the devices illustrated by FIGS. 10 and 11 which limit both the horizontal displacement and the rotation between these same parts. .

 As shown in FIG. 11, each device consists of a vertical plate 48 supported at 49 by the foundation or by AD1. This plate slides in a rectangular tube 50 which extends downwards from AD2.

Between the sides of the plate 48 and the tube are pads 51 of friction-reducing material which reduce the friction between the plate 48 and the tube 50. This arrangement is similar to that of the rings 147 and 247 described above.

As can be seen in FIG. 10, each plate 48 slides along its sides along a pair of opposite sides of the rectangular tube 50. Therefore, any horizontal displacement is prevented in a first direction. On the other hand, displacements are allowed in a second direction since the plate 48 is not as wide as the tube 50 in this second direction.

 Four tubes and four plates are used, in sets of two, which are perpendicular to each other.

Therefore, both games prevent any horizontal movement. In addition, they substantially prevent rotations. However these organs allow the thermal expansion and contraction of AD2 perpendicular to the plates 48; they are arranged so that these thermal movements are possible in all directions. The plates may be supported by tension (150) and shear bars (149) that break when the moments and shear forces become greater than a predetermined value.

 Figure 7 shows an alternative embodiment in which the superstructure is anchored to AD2 and AD1 is between AD2 and the foundation. In this case vertical columns are joined to AD1 and extend upwards around AD2. Moreover, as can be seen in fig. 7, the foundation is composed of several distinct parts, a provision that can be adopted also in the exemplary embodiment illustrated in FIG.

FIG. 15 illustrates an exemplary embodiment that is suitable for very large structures in which
AD2 is divided into several segments 60, e.g. 18 square meters, each of which supports a portion of AD1.

In the left part of Figure 15, the structure is represented with high AD2 and in the right part we can see AD2 lowered, which shows how the structure can move in the vertical direction. However, since AD2 is divided into five parts, the structure can be accommodated because at every moment parts of the soil that support it are at different levels from the other parts because of the seismic waves.

 According to this design, AD2 includes many columns or many vertical pillars extending up and down about 1.5 meters. Holes are provided in the foundation to receive the pillars AS2 and AC2 and to prevent the buckling of AS1.

 It is understood that the structure can be modified in its details and in its mode of operation without thereby going beyond the scope and spirit of the invention.

Claims (25)

 A structure supporting a superstructure and comprising isolation means for isolating said superstructure from the ground during an earthquake or other important oscillations of the ground, said insulating means comprising  a first load distribution platform (3) characterized in that it comprises  a second load distribution platform (4) substantially parallel to the first distribution platform (3), this first distribution platform (3) supporting the superstructure (1) and the other platform (3); 4) being arranged between the first platform (3) and the floor (5)  first elastic support means (7),  second elastic support means (10), said first elastic support means (7) joining a load distribution platform (3) and the other load distribution platform (4) and the second means (4) for distributing the load. elastic members (10) joining this other load distribution platform (4) and the ground (5)  means (8, 50) substantially opposing any shearing movement of one of the elastic support means (7) so as to allow substantially only rotational movements about a horizontal axis and substantially translational movements perpendicular to the load distribution platforms (3, 4) between the elements joined by one of the elastic support means (7), another means (50) being constructed and arranged to allow only substantially parallel translation movements at platforms (3, 4) for distributing the load and rotational movements about a vertical axis between the elements joined by the second elastic support means (10) so that the respective support members provide an insulation .  2. Structure according to claim 1 characterized in that it comprises means (6) substantially preventing movements between the elements joined by the second elastic support means (50) in a direction perpendicular to the platforms (3, 4) load distribution.  3. Structure according to claim 1 characterized in that the means substantially preventing any shear movement comprise columns (8) extending in said perpendicular direction.  4. Structure according to claim 3 characterized in that the columns (8) are spaced from one of the platforms (3) of load distribution by a small clearance (108) for thermal expansion.  5. Structure according to claim 1 characterized in that it comprises means (45, 47) preventing rotation between the elements joined by the first elastic means (50) of support.  6. Structure according to claim 5 characterized in that the means (45, 47) preventing rotation comprise a plate (48), means (149) joining this plate to one of the elements (49), a rectangular tube ( 50), means joining this tube (50) to the other of the elements (AD2), the plate (48) being introduced into the rectangular tube (50) with its edges being able to slide along the narrowest sides of the tube ( 50) and its main faces spaced from the longer sides of the rectangular tube (50), the members being movable toward and away from each other but substantially prevented from performing any translational movement relative to each other in the direction of the length of the plate (48) and any rotational movement about an axis perpendicular to the plate (48). the gap between the main faces thereof and the longer sides of the rectangular tube (50) for thermal expansion and contraction of the load distribution platforms (3, 4) in a direction perpendicular to said plate (48).  7. Structure according to claim 6 characterized in that it comprises at least two sets of plates (48) and tubes (50) with the plates (48) and the tubes (50) arranged perpendicularly to each other, said plates (48) and said tubes (50) being arranged so that thermal expansion and contraction are possible in all directions but that any rotational movement and relative translational movement parallel to the platforms (3, 4) of load distribution are substantially prohibited in all directions.  8. Structure according to claim 1 characterized in that the first elastic support means comprises an elongated column (56) of rubber, an elongate hollow cylinder (65) which receives the column (56), the latter being joined to the one of the elements and the cylinder (65) being joined to the other of the elements between which this elastic support means ensures the connection  9.Structure according to claim 1 characterized in that it comprises connecting means (AC2) joined to the elements which are connected by the first elastic means (8) of support, these connecting means (AC2) opposing resistance to movement between the elements in rotation and in translation perpendicularly to the platforms (3,4) of distribution of the load, this resistance being proportional to the speed of the movements, these connecting means (AC2) being constructed and arranged to be detached when the resistance is greater than a predetermined force, so that after strong accelerations have been imposed on the structure, the connecting means are detached and the structure is then supported by said elastic support means.  10. Structure according to claim 9 characterized in that the connecting means (AC2) comprise  a cylinder (20),  a piston (21) slidably mounted in the cylinder (20),  connection means (24,25,26) for transferring a fluid between spaces on opposite sides of the piston (21) to allow a fluid to flow between these spaces when the movement of the piston (21) repels this fluid  a piston rod (22) connected to the piston (21) and to one of the elements which are joined by the first elastic support means  means for joining the cylinder (20) to the other elements which are joined by the same elastic means, these connection means comprising connecting means (30, 31, 32) for disconnecting the cylinder (20) from the other element when it is subjected to a predetermined force.  11. Structure according to claim 10 characterized in that the connecting means for the circulation of the fluid is constituted by a tube (24) whose diameter is smaller than the diameter of the cylinder (20).  12. Structure according to claim 10 characterized in that the connecting means (30, 31, 32) comprise a rod (32) which extends through a wall of the cylinder (20), the rod (32) having a notch breaking (34), so  it breaks under the effect of the predetermined force.  13. Structure according to claim 1 characterized in that the second elastic means (10) of support comprise  a cylinder (12 ') which has an opening at one end,  a piston (15 ') slidably mounted in this cylinder,  a mass (13 ') of elastomer disposed inside the cylinder (12')  a carrier (41) extending inwardly from the inner face of the cylinder (12 '), between its ends; for supporting the elastomer mass (13 ') when compressed by the piston (15'), (42)  elastic means / s extending through the support (41) to push the mass (13 ') against the action of the piston (15') so that the free end of the piston (15 ') is constantly pushed towards the flat -form of load distribution (4) between the structure and the ground.  14. Structure according to claim 13 characterized in that it comprises a plate (18 ') in the vicinity of the free end of the piston (15') means (17 ') of friction reduction disposed between said free end and the plate (18 ') to allow a sliding movement between the latter and the free end in a direction parallel to the load distribution platforms (3, 4).  15. Structure according to claim 13 characterized in that the means (17 ') for reducing the friction consist of polytetrafluoroethylene.  16. Structure according to claim 1 characterized in that the other means preventing shearing movements comprises an elastomer column (44), a cylinder (45) fixed at one end of this column (44) and extending in direction axial from this end, a tube (47) receiving the cylinder (45) with a possibility of sliding, means for fixing the free end of the column (44) to one of the elements joined by the second means support elastics, fastening means of the tube tut7) to 1 other elements joined by the same elastic support means, so that following any movement between the elements in substantially parallel direction to the platforms ( 3, 4), the cylinder (45) slides into the tube (47).  17. Structure according to claim 16 characterized in that means (147, 247) for reducing the friction are interposed between the cylinder (45) and the tube (47).  18. Support pot forming part of the structure according to claim 1 for the insulation of the base of the latter, characterized in that it comprises  a cylinder (12 ') with an opening at one end,  a piston (15 '> slidably mounted by this end inside the cylinder  a mass (13 ') of elastomer disposed inside the cylinder  a support (41) extending internally from the inner face of the cylinder, between its ends, to support the mass (13 ') of elastomer when compressed by the piston (15')  elastic means (42) extending through the support (41) for urging the elastomer mass (13 ') against the piston (15') so that the free end of the piston (15 ') is continuously pressed against a structure in the case of a displacement in the direction of this support pot between said structure and a foundation.  19. Support pot according to claim 18 characterized in that it comprises a plate (18 ') associated with the free end of the piston (15') and means (17 ') of friction reduction arranged between this free end and said plate (18 ') to allow a sliding movement between the latter and the free end of the piston (15') in a direction perpendicular to the axis of the support pot.  20. Pot support according to claim 19 charac terized in that the friction reduction means are constituted by polytetrafluoroethylene.  21. Connecting device forming part of the structure according to claim 1 for the insulation of the base of this structure, characterized in that it comprises  a cylinder (20),  a piston (21) slidably mounted in this cylinder,  connecting means (24, 25, 26) for transferring a fluid between spaces on opposite sides of the piston (21) to allow a fluid to be transferred between these spaces when the movements of the piston ( 21) move this fluid,  a piston rod (22) joined to said piston (21) and extending out of the cylinder (20) in a first direction, said piston rod (22) being constructed to be joined to a portion of the structure  means (30, 31, 32) for connecting the cylinder (20) to another part of the structure, these means (30, 31, 32) comprising coupling means (34, 35) capable of uncoupling the cylinder ( 20) of this other part of the structure when they are subjected to a predetermined force, so that the connecting device allows slow movement between the respective parts of the structure but is out of action when a predetermined force is applied to these connecting means (30, 31, 32).  22. Connecting device according to claim 21 characterized in that the connection means for transferring the fluid is a tube (24) whose diameter is smaller than the diameter of the cylinder (20).  23. Connecting device according to claim 21 characterized in that the connecting means (30, 31, 32) comprise a rod (32) extending through a wall of the cylinder (20), the rod (32) having a notch (35) so that it breaks as a result of the application of said predetermined force.  24. An elastic elastomer device forming part of the structure according to claim 1 for controlling the horizontal movements of the latter, characterized in that the tool comprises an elastomer column (44), a cylinder (45) fixed at one end of this column. (44) and extending axially from this end, a tube (47) slidably receiving the cylinder (45), means for fixing the free end of the column (44) to a portion of the structure and means for fixing the tube (47) to another part of the structure, so that following a movement between the two parts of the structure to which this elastic device has been attached, in perpendicular direction at the axis of the elastomer column (44), the cylinder (45) slides in the tube (47).  25. Elastic device according to claim 24 characterized in that it comprises means (147, 247) for reducing the friction between the tube (45) and the cylinder (47).