EP3910108B1

EP3910108B1 - Reinforced dilatation joint for road and railroad applications

Info

Publication number: EP3910108B1
Application number: EP21173317.5A
Authority: EP
Inventors: Mauro Scaramuzza
Original assignee: Bearings And Joints Srl
Current assignee: Bearings And Joints Srl
Priority date: 2020-05-12
Filing date: 2021-05-11
Publication date: 2024-01-31
Anticipated expiration: 2041-05-11
Also published as: EP3910108A1

Description

The invention relates to a reinforced expansion joint for road and rail applications.
In particular, the present invention has as its object an expansion and waterproof joint, particularly designed for applications in the road and civil sectors, having a modular composition of studied elements of reinforced elastomer.
It is now known that one of the main functions of an expansion joint is to ensure the continuity of the road surface, ensuring the flatness thereof in order to ensure a smooth and comfortable driving even at the expansion joint itself. Another important function of an expansion joint is to allow the development of structural deformations, of a road section or a railway section, related to thermal variations or other factors, such as an earthquake. A prior art expansion joint is known from US 4 022 538 A .
In essence, the expansion joint must allow the increase or decrease in the size of the gap, or the space, existing between two opposing structural elements, where the change in the gap can be related to any phenomenon, or thermal gradient, or earthquake, or oscillation, or other phenomena involving a shift of the parts between which the gap is defined.
In practice, the purpose of an expansion joint is to ensure the load-bearing coverage of the gap underlying the joint in the field of the slidings for which the expansion joint is designed.
It is also essential that an expansion joint is able to guarantee the impermeability of the gap to which it is applied.
The expansion joint object of the present invention is referable to the type of joints identified as "bridge plate" expansion joints.
Basically, these are expansion joints in which the required sliding is developed by exploiting the shear deformation of flat rubber blocks suitably positioned with respect to each other.
These flat rubber blocks are connected together so as to form the real joint by means of rubber junction portions and vulcanized steel metal sheets within the same flat blocks.
It should be remembered that the technological process of vulcanisation is a well-known industrial process through which, by means of the combined action of heat and pressure, steel elements, also known as 'armature', placed together with raw rubber inside a mould, are made to adhere closely to the rubber itself, giving rise to a product having the same geometry as that of the mould used, at the same time giving the rubber making up the product mechanical characteristics according to the chemical characteristics of the rubber used.
Figures 1, 2 and 3 show schematically a typical example of a "bridge plate" type expansion joint in its neutral configuration (Figure 1), in the maximum contraction configuration (Figure 2), and in the maximum extension configuration (Figure 3), so as to make clear its operating principle.
An expansion joint of known type shown in Figures 1, 2 and 3 is wholly referred to therein as A1.
Such an expansion joint A1 comprises:

an upper central flat block B,
two lower lateral flat blocks C and D.

In the normal arrangement of use of the expansion joint A1, the upper central flat block B is placed above the two lower lateral flat blocks C and D, and is partially superimposed on them.
The flat blocks are developed in mutually parallel planes.
The upper central flat block B and the lower lateral flat blocks C and D are connected by means of respective elastically deformable junction sections E and F.
A metal reinforcing plate H1 is incorporated in the upper central flat block B and extends within the block itself substantially over its entire width and over its entire length.
Corresponding metal plates H2 and H3 are embedded also in the lower lateral flat blocks C and D.
The metal plates H2 and H3 allow the anchoring to the ground, by means of threaded fixing systems, of the lower lateral flat blocks C and D.
The expansion joint A1 also comprises end portions L and M developing upwards along the respective opposite edges of the lower lateral flat blocks C and D, at which the through holes for the ground anchoring screws are defined.
The upper surfaces of the upper central flat block B and the end portions L and M lie on the same plane, which in use is the transit plane, i.e., the plane on which the wheels of the vehicles run.
A gap K1 and K2 is defined between the upper central flat block B and an end portion L and M respectively, which gap widens or narrows according to the reciprocal movement of the two opposite road sections between which the expansion joint is fixed.
The flat blocks B, C and D, the junction sections E and F and the end portions L and M are integrated into a single plastic body, for example of vulcanized rubber, as described above.
The end portions L and M are not reinforced; such end portions L and M define a rest sidewall for a corresponding lateral screed for the connection to, for example, the road asphalt.
The geometric configuration shown in these figures 1, 2 and 3 is the typical configuration used by almost all manufacturers for the realization of expansion joints with maximum sliding, i.e., with a deformation in the direction of travel, up to 150 mm, that is joints with a maximum extension capacity of 75 mm and a maximum contraction capacity of 75 mm.
Above this sliding value, that is 150 mm, expansion joint manufacturers currently use "multiple" geometric configurations of the illustrated configuration, as exemplified in the section of figure 4.
For the expansion joints with a sliding capacity higher than 150 mm, the number of bridge plate elements indeed is increased and new elements are inserted, generally always in symmetry, referred to as 'transition elements', whose purpose is to increase the number of flat blocks of reinforced rubber that with their displacement guarantee the required performance to the expansion joint.
The expansion joint A2 of figure 4 comprises substantially the same elements as the expansion joint A1 of figures 1 to 3, with the addition of:

two upper lateral flat blocks W and S, positioned on opposite sides of the upper central flat block B, connected to the end portions L and M which define corresponding second junction sections L and M, and are added to the first junction sections E and F;
two external lower lateral flat blocks U and V, arranged externally to the two lower lateral flat blocks C and D;
elastically deformable junction sections R and T between the upper lateral flat blocks W and S and the external lower lateral flat blocks U and V.

Also in this known expansion joint A2 the external lower lateral flat blocks U and V comprise respective end portions Y and Z developing upwards along the respective opposite edges of the external lower lateral flat blocks U and V, at which the through holes for the ground anchoring screws are defined.
In this expansion joint A2 also the end portions Y and Z are reinforced by means of a steel profile H6 and H7 respectively, shaped like an "L", whose horizontal part allows the external lower lateral flat blocks U and V to be anchored to the ground, while the vertical part reinforces the central and upper part of the same end portion Y and Z.
This expansion joint A2 comprises four gaps K1, K2, K3 and K4.
The expansion joints A1 and A2 described above can change their length in the direction of travel, i.e., the direction in which the vehicles run over them, thanks to the elastically deformable junction sections E, F, L, M, R and T which, by deforming elastically in shear, allow the upper flat blocks to move away or closer.
The expansion joint A1 having two gaps K1 and K2 has two elastically deformable junction sections E and F.
The expansion joint A2 having four gaps K1, K2, K3 and K4 has instead six elastically deformable junction sections E, F, L, M, R and T.
The need to increase the number of flat blocks in reinforced rubber, as the need for the sliding of the expansion joint increases, derives from the limitations placed on some of the geometric elements that make this type of expansion joint.
The first limitation is related to the width of the single transversal gap of an expansion joint that one can have in the phase of maximum extension, that is the maximum distance in the direction of travel between two flanked upper flat blocks; this maximum width is fixed in literature at 80 mm, a value beyond which there is an exponential increase in the stresses transmitted by the wheels of transiting vehicles to the structure of the joint itself when these vehicles engage the gap.
The second limitation concerns the maximum tangential deformation imposed on the single junction sections connecting the flat blocks, which is comprised between values of 0.7 and 1.2 of the height value of the junction section itself.
Therefore, for slidings equal to and greater than 200 mm, that is between +100 mm and -100 mm, it is necessary to achieve this overall sliding by dividing and distributing the deformation over a number of elastically deformable junction sections greater than two, both in order to avoid too high, that is too thick, expansion joints and to avoid gaps greater than 80 mm at maximum extension.
At present, manufacturers of expansion joints are making this technical requirement a reality by arranging several elastically deformable junction sections in series, until the development and therefore the desired performance in terms of overall sliding are obtained.
It is evident how an expansion joint obtained in this way is characterized by a plurality of transversal gaps to each of which the development of a portion of the overall required sliding is assigned.
It is also evident that each transversal gap represents a direct source of noise when a gap is crossed and engaged by a wheel of a vehicle transiting on the expansion joint which, it is worth remembering, engages the transversal gaps in a direction, corresponding to the above-mentioned direction of travel, orthogonal to them with respect to their longitudinal development direction. The origin of the noise is constituted by the impact of the vehicle wheels on the edge "coming out" from the gap, an impact that, in addition to the noise produced, inevitably produces a dynamic stress on the expansion joint and from this to the structure.
The presence of the transversal gaps on expansion joints must be considered a "necessary evil", "evil" because they are a source of noise and dynamic stresses, "necessary" because these gaps are those allowing the required slidings of the joint.
The task of the present invention is to develop a reinforced expansion joint for road and rail applications capable of obviating the limitations and drawbacks of expansion joints known today.
In particular, one object of the invention is to develop a reinforced expansion joint capable of slidings higher than 150 mm while minimizing the number of gaps.
Another object of the invention is to develop a reinforced expansion joint which is quieter than the known type joints.
Again, one object of the invention is to develop a reinforced expansion joint that is more compact than expansion joints capable of slidings higher than 150 mm of known type.
The above-mentioned task as well as the above-mentioned objects are achieved by a reinforced expansion joint for road and rail applications according to claim 1.
Further features of the reinforced expansion joint according to claim 1 are described in the dependent claims.
The aforesaid task and objects, together with the advantages that will be mentioned hereinafter, are indicated by the description of an embodiment of the invention, which is given by way of non-limiting example with reference to the attached drawings, where:

figure 1 represents a sectional side view of a road expansion joint of known type, in a first operating arrangement;
figure 2 represents the expansion joint of figure 1 in a second operating arrangement;
figure 3 represents the joint of figures 1 and 2 in a third operating arrangement;
figure 4 represents a sectional side view of a further expansion joint of known type;
figure 5 represents a perspective view of a reinforced expansion joint according to the invention;
figure 6 represents a sectional side view of the reinforced expansion joint according to the invention in a first operating arrangement;
figure 7 represents a sectional side view of the reinforced expansion joint according to the invention in a second operating arrangement;
figure 8 represents a sectional side view of the reinforced expansion joint according to the invention in a third operating arrangement.

With reference to the above-mentioned figures, a reinforced expansion joint for road and rail applications according to the invention is indicated as a whole by numeral 10.
Said reinforced expansion joint 10 comprises:

an upper central flat block 11, inside which a reinforcement armature 12 is incorporated,
two lower lateral flat blocks 13 and 14, inside each of said lower lateral flat blocks 13 and 14 a respective reinforcement armature 15 and 16 being incorporated.

With respect to an arrangement of use, the upper central flat block 11 is placed above the two lower lateral flat blocks 13 and 14.
The upper central flat block 11 and the lower lateral flat blocks 13 and 14 are connected by means of respective first elastically deformable junction sections 17 and 18.
The reinforced expansion joint 10 according to the invention further comprises:

two upper lateral flat blocks 19 and 20, positioned on opposite sides of the upper central flat block 11, connected to said two lower lateral flat blocks 13 and 14 through corresponding second elastically deformable junction sections 21 and 22; the upper surfaces of the upper central flat block 11 and of the upper lateral flat blocks 19 and 20 lie on the same plane, which in use is a transit plane; the lower lateral flat blocks 13 and 14 lie below said transit plane;
two opposite end blocks 25 and 26, each developing from a said upper lateral flat block 19 and 20 downwards with respect to an arrangement of use;
a reinforcement armature 23 and 24, positioned inside each of the upper lateral flat blocks 19 and 20 and configured in such a way as to extend in the upper portion 25a and 26a of the respective end block 25 and 26;
an anchoring armature 27 and 28 positioned inside the lower part 25b and 26b of a corresponding end block 25 and 26.

A first variable width gap 40 is defined between the upper central flat block 11 and a first upper lateral flat block 19; a second variable width gap 41 is defined between the upper central flat block 11 and a second upper lateral flat block 20.
A lower variable width recess 42 and 43 is defined between a lower lateral flat block 13 and 14 and a corresponding flanked end block 25 and 26.
Said lower variable width recesses 42 and 43 are configured to each define an external lateral variable width gap, each external lateral variable width gap being placed below a corresponding upper lateral flat block 19 and 20.
Such lower variable width recesses 42 and 43 substantially define 'covered' or inverted gaps, thanks to which the movement away from or approach between a lower lateral flat block 13 and 14 and a corresponding flanked end block 25 and 26 is permitted as if there were a gap open upwards in a known manner, but without having the interruption of the structural continuity caused by a normally upwards facing gap.
The reinforcement armatures 12, 23, 24 of the upper central flat block 11 and of the upper lateral flat blocks 19 and 20 respectively each comprise at least one upper metal plate.
Such upper metal plates develop on the same reference plane P.
The reinforcement armature 12 of the upper central flat block 11 comprises a main metal plate 12a and an auxiliary metal plate 12b.
Said auxiliary metal plate 12b is placed below the main metal plate 12a.
The reinforcement armatures 15 and 16 and the anchoring armatures 27 and 28 each comprise at least one respective lower metal plate.
A central portion 25c and 26c of the end blocks 25 and 26 is sandwiched between an outer zone 23a and 24a of the reinforcement armature 23 and 24 of a said corresponding upper lateral flat block 19 and 20 and a corresponding anchoring armature 27 and 28.
The upper central 11, lower lateral 13 and 14, upper lateral 19 and 20 flat blocks, the end blocks 25 and 26 and the elastically deformable junction sections 17, 18, 21, 22 are part of a single body made of plastic material.
The reinforcement armatures 12, 15, 16, 23, 24 and the anchoring armatures 27, 28 are embedded and incorporated inside said single body in plastic material.
In particular, the single plastic body is made of vulcanized synthetic rubber. Each of said end blocks 25 and 26 comprises niches 30 for accessing the respective anchoring armature 27 and 28.
The anchoring armatures 27 and 28 are known to have through holes for inserting a threaded fastener, such as a threaded bar, for fixing to an underlying slab.
The reinforced expansion joint 10 according to the invention therefore has a metal plate, i.e., the corresponding reinforcement armature 23 and 24, also in each of the two opposite end blocks 25 and 26 which opposite end blocks 25 and 26 are directly on the border with the road pavement, except for a lateral cement mortar screed not illustrated for simplicity's sake and of a type known in itself.
In this way, the wheels of a vehicle immediately find a stable support from the very first approach to the reinforced expansion joint 10, unlike to what happens with the known expansion joints exemplified in Figures 1 and 4, where the corresponding end portions L and M, Y and Z have no reinforcement armature in the upper part developing over the whole extension of the upper part itself.
In this way, the end blocks 25 and 26 develop their deformation below the corresponding reinforcement plate 23 and 24, i.e., the reinforcement armature 23 and 24 which protects the respective lower recess 42 and 43 underlying it from the impact of the vehicle wheels.
The result is a reinforced expansion joint 10 that is more compact, quieter and less impactful to the structure.
A further advantage of positioning the first reinforcement plate 23 and 24, i.e. of the reinforcement armature 23 and 24 of the end blocks 25 and 26, at the extrados of the reinforced expansion joint 10, is that this first reinforcement plate 23 and 24 contributes to the transverse stiffening of the joint itself, working as a "sandwich" with the anchoring zone in which the anchoring reinforcement 27 and 28 is positioned on which slotted through holes are obtained, for the insertion of the anchoring screws for which said anchoring reinforcement acts as a contrast for their tightening.
As can be seen in figure 4, nowadays the stiffening of the end blocks, if any, is carried out using a steel profile, indicated with H6 and H7 in figure 4, usually shaped as an "L", as a reinforcement element in the anchoring zone.
This "L" stiffening is not able to support the load of a wheel transiting on the end portion Y and Z with consequent inhomogeneous crushing of the end portion Y and Z itself, and consequent generation of an effective gap K3 greater than the ideal expected one.
During the vulcanization phase, a slotted recess 30 is obtained in the rubber thickness placed at the slotted hole, in order to allow the housing of the head and of the relative washer of the anchoring screw, so that nothing protrudes from the thickness of the synthetic rubber body of the reinforced expansion joint 10 and so that it cannot in any way interfere with the flow of the vehicles on it.
This technical solution can obviously be used for any reinforced expansion joint, both for road and rail use, and above all for any sliding interval, preferably but not limited to, higher than 100 mm.
It has in practice been established that the invention achieves the intended task and objects.
In particular, a reinforced expansion joint 10 has been developed by the invention, which makes it possible to reduce to only two, that is, the gaps 40 and 41 in figures 6, 7 and 8, the gaps required to make an expansion joint having a total sliding capacity equal to and greater than 200 mm, instead of four gaps like in the joints of the known type.
In particular, with the invention, a reinforced expansion joint has been developed which is quieter than known type joints, due to the halved number of gaps, i.e., zones of increased noise at the transit of vehicle wheels.
In addition, with the invention, a reinforced expansion joint has been developed which is more compact than the expansion joints capable of slidings greater than 150 mm of the known type, and which therefore requires less space in the direction of travel, and fewer special materials to be set up.
The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept; moreover, all the details may be replaced by other technically equivalent elements.
In practice, the components and materials used, as long as they are compatible with the specific use, as well as the contingent dimensions and shapes, can be any according to the needs and the prior art.
Where the characteristics and techniques mentioned in any claim are followed by reference notes, such reference notes should be intended as having been added for the sole purpose of increasing the intelligibility of the claims and consequently such reference notes have no limiting effect on the interpretation of each element identified by way of example by such reference notes.

Claims

Reinforced expansion joint (10) for road and rail applications, comprising:
- an upper central flat block (11), inside which a reinforcement armature (12) is incorporated;

- two lower lateral flat blocks (13, 14), inside each of said lower lateral flat blocks (13, 14) a respective reinforcement armature (15, 16) being incorporated,
with respect to an arrangement of use, said upper central flat block (11) being placed above said two lower lateral flat blocks (13, 14),

said upper central flat block (11) and said lower lateral flat blocks (13, 14) being connected by means of respective first elastically deformable junction sections (17, 18),

said reinforced expansion joint (10) comprising:
- two upper lateral flat blocks (19, 20), positioned on opposite sides of the upper central flat block (11), connected to said two lower lateral flat blocks (13, 14) through corresponding second elastically deformable junction sections (21, 22), the upper surfaces of said upper central flat block (11) and of said upper lateral flat blocks (19, 20) lying on the same plane, which in use is a transit plane, said lower lateral flat blocks (13, 14) lying below said transit plane;

- two opposite end blocks (25, 26), each developing from a said upper lateral flat block (19, 20) downwards, with respect to an arrangement of use;

- a reinforcement armature (23, 24), positioned inside each of said upper lateral flat blocks (19, 20) and configured in such a way as to extend in the upper part (25a, 26a) of the respective end block (25, 26);

- an anchoring armature (27, 28) positioned inside the lower part (25b, 26b) of a corresponding end block (25, 26);

a first variable width gap (40) being defined between said upper central flat block (11) and a said first upper lateral flat block (19), a second variable width gap (41) being defined between said upper central flat block (11) and a said second upper lateral flat block ( 20), a lower variable width recess (42, 43) being defined between a said lower lateral flat block (13, 14) and a corresponding flanked end block (25, 26), said lower variable width recesses (42, 43) being configured to each define an external lateral variable width gap, each external lateral variable width gap being placed below a corresponding upper lateral flat block (19, 20), characterized in that the reinforcement armature and anchoring armature are vulcanized within the respective blocks and a central portion (25c, 26c) of said end blocks (25, 26) is sandwiched between an outer zone (23a, 24a) of said reinforcement armature (23, 24) of a said corresponding upper lateral flat block (19, 20) and a said corresponding anchoring armature (27, 28).
Reinforced expansion joint according to claim 1, characterized in that said reinforcement armatures (12, 23, 24) of said upper central flat block (11) and of said upper lateral flat blocks (19, 20) each comprise at least an upper metal plate, said upper metal plates developing on the same reference plane (P).
Reinforced expansion joint according to one or more of the preceding claims, characterized in that said reinforcement armatures (15, 16) and said anchoring armatures (27, 28) each comprise at least one respective lower metal plate.
Reinforced expansion joint according to one or more of the preceding claims, characterized in that said upper central (11), lower lateral (13, 14), upper lateral (19, 20) flat blocks, said end blocks (25, 26) and said elastically deformable junction sections (17, 18, 21, 22) are part of a single body made of plastic material.
Reinforced expansion joint according to one or more of the preceding claims, characterized in that said reinforcement armatures (12, 15, 16, 23, 24) and said anchoring armatures (27, 28) are embedded and incorporated inside said single body in plastic material.
Reinforced expansion joint according to claim 4, characterized in that said single plastic body is made of vulcanized synthetic rubber.
Reinforced expansion joint according to one or more of the preceding claims, characterized in that each of said end blocks (25, 26) comprises niches (30) for accessing the respective anchoring armature (27, 28).