"ANTI-SEISMIC CONNECTION JOINT"

FIELD OF THE APPLICATION

[0001] The present invention concerns an anti-seismic connection joint. In particular, the present invention has as its subject an anti-seismic connection joint for prefabricated structures in prestressed or normal reinforced concrete.

STATE OF THE ART

[0002] Some examples of anti-seismic connection joints for buildings are known in the state of the art, which are adapted to allow the structural framework of the existing or new building, to which they are applied, to adequately withstand the seismic forces and absorb the deformations that occur as a result of seismic events.

[0003] In particular, an anti-seismic joint creates an adequate connection between the main structural elements of the building (pillars, beams, slabs, trusses, purlins, etc.), essential to prevent serious damage and collapse during an earthquake. In effect, precisely because of seismic events, adjacent components of the same structure normally designed in simple support, with a significantly different seismic behavior, suffer relative movements, and risk bumping into each other and undergoing serious damage or, in extreme cases, falling, due to loss of support, at the various connections. At the same time, an anti-seismic joint must always allow free expansion of the building structure due to seasonal variations in temperature, preventing damage and cracking from occurring .

[0004] In particular, since industrial buildings are the preferred field of application, it is essential for the anti-seismic joint to be suitable to adequately withstand not only the first seismic shock, but also all subsequent shocks .

PRESENTATION OF THE INVENTION

[0005] The need perceived in the field of earthquake- resistant construction is to create, in compliance with the regulations and also on existing buildings, a structural connection between the components of the building that is able to adequately withstand the seismic event throughout its duration.

[0006] In addition, a further perceived need is that of an anti-seismic joint in which there is an indicator relating to the forces that have occurred during the earthquake .

[0007] Furthermore, there is a need for an anti-seismic joint that is suitable for dissipating and/or damping the forces involved during an earthquake.

[0008] The object of the present invention is to solve at least partially the problems of the prior art while taking into account the needs of the industry.

[0009] This object is achieved by an anti-seismic connection joint made in accordance with claim 1.

[0010] The dependent claims describe preferred or advantageous embodiments of the anti-seismic connection joint .

DESCRIPTION OF THE DRAWINGS

[0011] Further features and advantages of the present invention will become more apparent from the following description of the preferred and non-limiting examples of embodiment thereof, wherein:

- Figure 1 shows schematically a possible embodiment of an anti-seismic connection joint between slabs and beams according to the present invention;

- Figure 2 shows schematically an alternative embodiment of an anti-seismic connection joint between slabs and beams according to the present invention;

- Figure 3 shows schematically a cross section of a possible embodiment of an anti-seismic connection joint between slabs and beams according to the present invention, in the case of narrow slabs;

- Figure 4 shows schematically a cross section of a possible embodiment of an anti-seismic connection joint between slabs and beams according to the present invention, in the case of flat bottom slabs;

- Figure 5 shows schematically a longitudinal section of a possible embodiment of an anti-seismic connection joint between slabs and beams according to the present invention, in the case of flat bottom slabs;

- Figure 6 shows schematically a longitudinal section of a possible embodiment of an anti-seismic connection joint between slabs and beams according to the present invention, in the case of narrow slabs;

- Figure 7 shows schematically a perspective view of a possible embodiment of an anti-seismic connection joint according to the present invention;

- Figure 8 shows schematically a side view of the connection joint in Figure 7;

- Figure 9 shows schematically a possible alternative embodiment with respect to Figure 8, suitable for narrow beams ;

- Figure 10 shows schematically a cross section of the connection joint in Figure 8;

- Figure 11 shows schematically a cross section of the connection joint in Figure 9; and

- Figure 12 shows schematically a bottom view of the connection joint in Figure 7.

[0012] The elements or parts of elements in common between the embodiments described hereinafter will be indicated at the same numerical references.

DETAILED DESCRIPTION

[0013] With reference to the accompanying figures, an anti- seismic connection joint is indicated at the reference number 100.

[0014] The anti-seismic connection joint 100 comprises:

- a first element 10 (or female element) adapted to be arranged on a first structural component 110, and

- a second element 20 (or male element) adapted to be arranged on a second structural component 120.

[0015] The structural components 110, 120 may be, for example, a pillar and a beam, or a beam and a slab. Obviously, this reference is in no way restrictive with respect to the possible applications of the joint according to the present invention.

[0016] The first element 10 may comprise a connection plate 11 adapted to be attached to the first structural component 110, and the second element 20 may comprise a connection plate 21 adapted to be attached to the second structural component 120.

[0017] The fastening of the first element 10 and of the second element 20 may be carried out with fastening means 90, such as, for example, screws and bolts, chemical anchors, metal bindings.

[0018] In the embodiments shown in the accompanying figures, the fastening means comprise screws and bolts.

In this regard, the connection plates 11, 21 may be provided with holes 91, preferably oval in shape to allow for a plurality of screw or bolt positions within the hole, so as to avoid the internal reinforcement of the structural component.

[0019] In a possible alternative embodiment, the connection plates 11, 21 may be provided with lateral shoulders

(Figures 3, 6, 9, 11) for attachment along the sides around the structural components 110, 120, for example, when such structural components 110, 120 do not allow the insertion of screws along the base because it is too narrow .

[0020] The first element 10 is provided with two lateral flanges 14, 16, each comprising at least one hole 142,

162, with the holes 142, 162 aligned with each other.

[0021] The second element 20 is provided with a central plate 24 comprising at least one hole 242, 244, 246, 248.

[0022] The central plate 24 is interposed between the lateral flanges 14, 16, and at least one hole 242, 244,

246, 248 of the central plate 24 is aligned with the respective holes 142, 162 of the lateral flanges 14, 16.

[0023] The connection joint 100 comprises:

at least one dissipation bar 72, 74, 76, 78 passing through the at least one hole 142, 162 of each flange 14 16, and passing through said at least one hole 242, 244

246, 248 of the central plate 24; and

- stop means 25 for said at least one dissipation bar 72, 74, 76, 78, placed at the ends of said dissipation bar 72, 74, 76, 78.

[0024] According to a possible embodiment, the stop means 25 are obtained by means of an at least partial threading of the at least one dissipation bar 72, 74, 76, 78, so that it may be locked onto the flanges 14, 16 by means of nuts 73 screwed to the protruding ends of the bar 72, 74, 76, 78 from the flanges 14, 16.

[0025] In the embodiment shown in the example in Figure 2, the stop means 25 comprise transverse holes 251 near the ends of the said at least one dissipation bar 72, 74, 76, 78, and cotter pins 253 inserted into such transverse holes 251.

[0026] Advantageously, the dissipation bars 72, 74, 76, 78, may be smooth, i.e. without threads.

[0027] According to a possible embodiment, the dissipation bars 72, 74, 76, 78 are parallel to each other.

[0028] Advantageously, at least one dissipation bar 72, 74, 76, 78 may be parallel to the hinge axis 26.

[0029] In particular, in the embodiment shown in figures 1-

6, the dissipation bars are three, and lie on the same plane . According to alternative embodiments the dissipation bars may have different position planes from each other.

[0030] As shown in the example in figures 5 and 6, the holes 242, 244, 246, 248 of the central plate 24 may be slotted. In this case, the slotted holes allow a relative movement between the first element 10 and the second element 20 before the dissipation bars are subjected to deformation. According to a possible embodiment of the present invention, the holes 242, 244, 246, 248 may be elongated in the direction of sliding between the first element 10 and the second element 20.

[0031] According to a possible embodiment of the present invention, at least one of the holes 242, 244, 246, 248 of the central plate 24 has different dimensions from the others. In this case, the dissipation bars will begin to flex at different times, depending on the amount of relative movement between the first element 10 and the second element 20.

[0032] The at least one dissipation bar may, for example, be made of 8.8 steel. Alternatively, the dissipation bars may also be made from other metals and/or alloys thereof (e.g. aluminum, bronze, copper) or from carbon composite materials (e.g. obtained with carbon fibers, thermosetting resin and bi-directional glass fiber fabrics) . [0033] With particular reference to figures 5 and 6, the anti-seismic connection joint may comprise a block 15 adapted to limit the relative movement between the first element 10 and the second element 20. In particular, the block 15 may limit the sliding of the second structural component 120 over the first structural component 110. According to a possible embodiment of the present invention, the block comprises a recess 152 in a portion of the edge of the central plate 24 and an abutment 154 in a portion of the first element 10.

[0034] In the embodiment shown in Figure 7, the first element 10 and the second element 20 are joined by a pin 30 to form a connecting hinge 40 between the structural components 110, 120. The connecting hinge defines a hinge axis 26.

[0035] Thus, the anti-seismic connection joint 100 connects, for example, vertical and horizontal structural components and at the same time, being a hinged joint, decouples the masses so that the vibratory movement caused by seismic events occurs freely for each of the two connected parts.

[0036] The anti-seismic connecting joint 100 may comprise at least one fuse device 28 comprising:

- a first plate 280 provided with a first hole 281 and a third plate 284 provided with a third hole 285 protruding from the first element 10; and

- a second plate 282 provided with a second hole 283 protruding from the second element 20.

- at least one sacrificial element 70.

[0037] The first hole 281, the second hole 283, and the third hole 285 are aligned with each other and the sacrificial element 70 is inserted within the holes 281, 283, 285.

[0038] The sacrificial element 70 is provided with locking means 82, 88 placed at its protruding portions 702, 704 from the first plate 280 and from the third plate 284.

[0039] The sacrificial element 70 is equipped, straddling the second plate 282, with adjustment-locking means 84, 86, such as to allow relative displacements between the first element 10 and the second element 20 able to take into account the thermal expansion.

[0040] Furthermore, the sacrificial element 70 is provided with at least one planned breaking portion 706, 708.

[0041] Advantageously, the plates 280, 282, 284 may be spaced out from each other and have a parallel position.

[0042] Advantageously, the sacrificial element 70 may be provided with two planned breaking portions 706, 708.

[0043] According to a possible embodiment, the first element 10 comprises two flanges 14, 16 equipped with respective flange holes 144, 164 for accommodating the pin 30, and the second element 20 may comprise a container cylinder 60 inside which is inserted the pin 30.

[0044] Thus, the joint 100 may realize the hinged connection through the interposition of the container cylinder 60 between the two flanges 14, 16, and with the insertion of the pin 30.

[0045] The pin 30 may be locked in position with end nuts 32, 34 and/or cotter pins (not shown) .

[0046] According to a possible embodiment of the present invention, the first plate 280 and the third plate 284 protrude from a flange 14, 16 of the first element 10, and have a position parallel to the hinge axis 26. Moreover, the first plate 280 and the third plate 284 may have a position perpendicular to the position of the flange 14, 16 to which they are connected.

[0047] The second plate 282 may protrude from the connection plate 21. In addition, the second plate 282 may have a position perpendicular to the connection plate 21.

[0048] With reference to figure 7, note that the second plate 282 is interposed between the first plate 280 and the third plate 284, so that the holes 281, 283, 285 are aligned with each other.

[0049] According to a possible embodiment, the fuse devices 28 may be two.

[0050] A first fuse device 28 may be arranged in such a way that a first plate 280 and a third plate 284 are arranged to protrude from the flange 14, and a first plate 280 and a third plate 284 are arranged to protrude from the flange 16. In this case, the two pairs of flanges 14, 16 are arranged in such a way that their position is normal to the hinge axis 26. In addition, there are two second plates 282 protruding from the connection plate 21, so that one of the second plates 282 is interposed between the pair of plates on the flange 14 and the other second plate 282 is interposed between the pair of plates on the flange 16.

[0051] Advantageously, the second plate 282 may have a position perpendicular to the connection plate 21.

[0052] The sacrificial element 70 may comprise a bar at least partially threaded, which protrudes externally relative to the first plate 280 and the third plate 284. According to a possible embodiment of the present invention, the sacrificial element 70 may be made from a threaded bar by turning the planned breaking portions 706, 708.

[0053] Advantageously, the sacrificial element 70 may be made of steel, for example 10.9 steel.

[0054] According to alternative embodiments the sacrificial element 70 may also be made with other types of metal, such as, for example, aluminum, bronze, copper, or with carbon composite materials, for example obtained with carbon fibers, thermosetting resin and bi- directional glass fiber fabrics.

[0055] The locking means 82, 88 are adapted to lock rigidly the position of the sacrificial element 70 with respect to the plates 280 and 284, while the adjustment-locking means 84, 86 are provided for locking on the plate 282 only in the case of displacements exceeding predetermined values (projected thermal expansion) .

[0056] According to a possible embodiment of the present invention, the locking means may be arranged on the ends or protruding portions 702, 704 of the sacrificial element 70. While the adjustment-locking means 82, 86 may be arranged:

- between the first plate 280 and the second plate 282, so that the distance relative to the second plate 282 may be adjusted; and

[0057] - between the second plate 282 and the third plate

284, so that the distance relative to the second plate 282 may be adjusted.

[0058] Advantageously, the locking means 82, 88, and the adjustment-locking means 84, 86 may comprise nuts that may be screwed onto threaded portions of the sacrificial element .

[0059] In particular, with reference to Figure 7, the nuts 82, 84, 86, 88 may be arranged as follows:

- a first nut 82 may be arranged on the protruding portion 702 of the first plate 280,

- a second nut 84 may be arranged between the first plate 280 and the second plate 282;

- a third nut 86 may be arranged between the second plate 282 and the third plate 284; and

- a fourth nut 88 may be arranged on the portion 704 protruding from the third plate 284.

[0060] The external nuts 82, 88 are called containment nuts, and the internal nuts 84, 86 are called adjustment nuts .

[0061] Advantageously, the adjustment-blocking means 84, 86 may be adjusted to allow relative displacements between the first element 10, and the second element 20, displacements due, for example, to seasonal temperature variations. This displacement results in a relative movement between the plates 280, 282, 284.

[0062] According to a possible embodiment of the present invention, the adjustment-locking means may be adjusted to allow a longitudinal displacement of the sacrificial element 70 of about 4 mm in one direction and 4 mm in the opposite direction. [0063] In this way, the sacrificial element 70 may be stressed only in traction.

[0064] In particular, depending on the direction of relative movement between the first element 10 and the second element 20, one of the two planned breaking portions 706, 708 will be stressed by the coupling between the pairs of bolts 84, 88 or 82, 86.

[0065] Therefore, the at least one fuse device 28 is adapted to prevent the relative movements between the connected parts until a stress threshold is reached.

[0066] When a certain stress threshold is exceeded, which may be predetermined at the design stage by appropriately sizing the section of the planned breaking portion, the connection joint 100 allows (even if in a limited way) the relative movements between the connected parts.

[0067] In the embodiment in figures 7-12, the joint 100 comprises four dissipation bars 72, 74, 76, 78, fixed at their ends to the flanges 14, 16. In addition, the container cylinder 60 is provided with a central plate 24 provided with holes 242, 244, 246, 248, wherein are inserted dissipation bars 72, 74, 76, 78. As shown in the embodiment in Figure 7, they may advantageously be placed at the vertices of a square or a rectangle. Also in this case, it may be envisaged the embodiment of the stop means 25 comprising through holes 251 in proximity of the ends of the said at least one dissipation bar 72, 74, 76

78, and cotter pins 253 inserted in these transverse holes 251.

[0068] Advantageously, the holes 242, 244, 246, 248 provided in the central plate 24 may be slotted. As previously mentioned, the slotted shape of at least one of the holes 242, 244, 246, 248 allows a relative displacement between the first element and the second element, before the dissipative effect of the dissipation bars 72, 74, 76, 78 is triggered.

[0069] In this regard, the holes 242, 244, 246, 248 may be sized differently so that the dissipative effect has a progressive character.

[0070] In the embodiment shown in Figure 7, the holes 242, 246 are more elongated than the holes 244, 248. For this reason, at a determined stress value, the dissipative effect relative to the dissipation bars of the holes 244, 248 will enter into operation. Subsequently, with higher stress values, the dissipative effect of the dissipation bars of the holes 242, 246 will also enter into operation .

[0071] The energy dissipation occurs due to the cyclic deformation of at least one dissipation bar 72, 74, 76,

78, subjected to bending in the plastic field during seismic events. In essence, the system may be described as a beam on two supports with a central load, the latter relating to the displacement of the central plate 24 with respect to the flanges 14, 16.

[0072] During the complete cycle of a seismic tremor, a first deformation of the threaded bars is obtained, followed by a straightening, a second deformation towards the opposite side and a final straightening, with the advantage for the system of dissipating energy during all stages of the cycle.

[0073] The dissipation bars 70, 72, 74, 76 generate a damping, and a considerable dissipation of energy produced by the axial stresses that occur as a result of seismic events.

[0074] Advantageously, the dissipation bars 72, 74, 76, 78 may easily be adapted, for example, by varying the diameter or the features of the material used to the different structural and dimensional situations of each case and to specific design requirements.

[0075] As previously mentioned, the connection hinge 40 allows the axial and transverse stresses of the structure, and in particular of the structural components 110, 120, which are caused by seismic events, to be absorbed.

[0076] In addition, the connection hinge 40 allows the free expansion of the same structural components 110, 120 due to seasonal variations in temperature.

[0077] The connection hinge 40 may be provided with a damping element 50.

[0078] The damping element 50 may be positioned between the first element 10 and the second element 20. In particular, the damping element 50 may be positioned within the connection hinge 40, thus damping the axial stresses caused by seismic events.

[0079] In particular, by defining the hinge axis 26 and a damping plane orthogonal to the hinge axis 26, the damping element 50 dampens the forces having at least one component in the damping plane .

[0080] The damping element 50 may be positioned around the pin 30. In particular, the damping element 50 prevents the pin 30 from shearing and/or deteriorating due to the sudden and prolonged unforeseen displacements of the oscillatory type that occur during seismic events.

[0081] The damping element 50 may be housed within the container cylinder 60 of the second element 20. The assembly is then joined by the pin 30, which runs longitudinally through the damping element 50, to form the connection hinge 40.

[0082] The damping element 50 may be made of natural and/or synthetic rubber, in different "hard" "medium" or "soft" compounds. The damping element 50 may therefore be made of low-, medium- or high-density rubber, depending on the damping needs to be given to the anti-seismic joint 100. It is therefore possible to modify the damping capacity of the anti-seismic connection joint 100 according to the requirements of use by simply changing the damping element 50.

[0083] The joint shown in Figure 7, which comprises at least one fuse device, one dissipation device and one damping device, is adapted to allow the structural components to absorb both the deformations that occur slowly over time, such as thermal deformations or shrinkage, and the forces resulting from dynamic and impulsive seismic actions.

[0084] The sacrificial element 70, being much more rigid than at least one dissipation bar 72, 74, 76, 78, acts as a fuse with brittle type breakage, while the dissipation bars dissipate energy by exploiting the ductility of the material used.

[0085] Once the sacrificial element has broken in at least one of the planned breaking portions as a result of stress, the joint, during subsequent stress, remains active with regard to the dissipation device and damping device. In particular, it allows relative displacements between the connected parts, of a predefined magnitude compatible with the dimensional features of the various structural components involved.

[0086] The anti-seismic joint 100 is therefore used in buildings, for example industrial buildings, such as warehouses (of new construction or already constructed and in use) .

[0087] Advantageously, the connection joint 100 according to the present invention, provides a suitable and safe structural connection applicable to all the components (beam-pillar, beam-slab) both along the main axial direction and in the inclined or transverse directions without causing a hyperstatic condition of the same structure .

[0088] The fuse devices allow the transition between the operating load condition and the seismic condition to be controlled.

[0089] Advantageously, the connection joint 100 guarantees a safe and adequate mechanical connection between beams and pillars or between other structural elements present in prefabricated structures in reinforced concrete and prestressed reinforced concrete, in full compliance with existing regulations.

[0090] Advantageously, the presence of the damping element within the hinge-type anti-seismic connection joint provides a further damping of the axial stresses of the vertical structures. [0091] Advantageously, the anti-seismic joint described above may be made with universal geometric and dimensional characteristics, produced in different sizes and applied in several juxtaposed specimens.

[0092] Advantageously, the constructive characteristics of the anti-seismic joint described above allow easy inspection of the various components and rapid replacement of worn parts following seismic events.

[0093] To the embodiments described above, the person skilled in the art may, in order to satisfy specific needs, make changes to or replacements of the described elements with equivalent elements without thereby departing from the scope of the accompanying claims.