ASEISMIC DEVICE

Abstract

An aseismic device has a flexural dissipator intended to be fixed to a first structural element, a sliding element having a sleeve closed as a ring around the flexural dissipator and slidingly mounted on the flexural dissipator, a connector intended to be connected to a second structural element, an axial dissipator connecting the connector to the sliding element, a first hinge disposed between the axial dissipator and the sliding element, and a second hinge disposed between the axial dissipator and the connector.

Claims

1. Aseismic device comprising: a flexural dissipator composed of a deformable bar intended to be fixed to a first structural element, said flexural dissipator having a longitudinal axis (X), a sliding element slidingly mounted on the flexural dissipator to slide along the longitudinal axis (X) of the flexural dissipator, a connector intended to be connected to a second structural element, an axial dissipator connecting said connector to said sliding element, said axial dissipator comprising a bracket composed of a U-shaped plate intended to be deformed with both compressive and tractive axial stress along a transversal axis (Z) that is substantially orthogonal to the longitudinal axis (X), a first hinge disposed between the axial dissipator and the sliding element to let the axial dissipator rotate with respect to the sliding element around a vertical axis (Y) orthogonal to the longitudinal axis (X) and to the transverse axis (Z), and a second hinge disposed between the axial dissipator and the connector to let the axial dissipator rotate with respect to the connector around an axis (X1) of the second hinge that is parallel to the longitudinal axis (X) of the flexural dissipator; wherein said sliding element comprises a sleeve closed as a ring around said flexural dissipator.

2. The aseismic device of claim 1, wherein said flexural dissipator is hinged to flanges intended to be connected to said first structural element so as to rotate around an axis (X2) that is parallel to the longitudinal axis (X) of the flexural dissipator.

3. The aseismic device of claim 1, wherein said sliding element comprises plates or Teflon inserts that act as sliding bearings disposed inside said sleeve to slide against a front edge and a rear edge of said flexural dissipator.

4. The aseismic device of claim 1, wherein said bracket of the axial dissipator comprises a base facing said connector and two wings orthogonal to the base and facing said flexural dissipator; said two wings being arranged on planes mutually parallel and parallel to said transverse axis (Z).

5. The aseismic device of claim 4, wherein said two wings of the bracket of the axial dissipator are arranged on planes above and below the longitudinal axis (X) of the flexural dissipator.

6. The aseismic device of claim 1, wherein said first hinge comprises screws that are passed through holes obtained in said wings of the plate of the axial dissipator and engage with holes obtained in said sliding element.

7. The aseismic device of claim 1, wherein said second hinge comprises two flanges connected to said connector and screws that are passed through slots of the flanges of the hinge and engaged with a nut fixed inside said axial dissipator.

8. The aseismic device of claim 7, wherein said axial dissipator comprises a wing fixed to the base of said plate and to said nut.

9. The aseismic device of claim 1, wherein said connector comprises: guide means intended to be fixed to the second structural element, and sliding means connected to said second hinge and slidingly mounted in the guide means so as to translate along an axis parallel to the vertical axis (Y) of the first hinge.

10. The aseismic device of claim 9, wherein said guide means comprise two guides; said sliding means comprise two carriages slidingly mounted in each guide and friction means provided in the carriages and in the guides that cooperate to control the movement of the carriages in the guides; and said connector comprises bolts fixed to the carriages and to said flanges of the second hinge.

11. The aseismic device of claim 2, wherein said flanges have an L-shaped section with a first wing intended to be fixed to the first structural element and a second wing fixed to the flexural dissipator, said first wings of the two flanges being provided with slots that are disposed orthogonally and receive inserts intended to be fixed in the first structural element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0056] With reference to the figures, the aseismic device of the invention is described, which is generally indicated with reference numeral 1.

[0057] FIG. 1 shows a first structural element (T), such as for example a beam, and a second structural element (P), such as for example a panel or a wall of a building. The second structural element (P) is intended to be connected to the first structural element (T) by means of the aseismic device (1). In the following description the terms transverse and longitudinal refer to the transverse and longitudinal direction of the first structural element (T), respectively.

[0058] When the first structural element (T) is connected to the second structural element (P), an internal surface (P1) of the second structural element is stopped against a longitudinal edge of the first structural element (T). The first structural element (T) has an upper surface (T1) orthogonal to the internal surface (P1) of the second structural element.

[0059] With reference to FIGS. 2 and 3, the aseismic device (1) comprises: [0060] a flexural dissipator (2) composed of a deformable bar intended to be fixed to the first structural element (T), [0061] a sliding element (4) slidingly mounted on the flexural dissipator (2), [0062] a connector (C) intended to be connected to a second structural element (P), and [0063] an axial dissipator (8) connected to said connector (C) and to said sliding element (4).

[0064] The flexural dissipator (2) has a longitudinal axis (X). The flexural dissipator (2) is fixed above the upper surface (T1) of the first structural element (T) so that the longitudinal axis (X) of the flexural dissipator is parallel to the longitudinal axis of the first structural element (T).

[0065] The axial dissipator (8) is extended or contracted along a transverse axis (Z) orthogonal to the longitudinal axis (X) of the flexural dissipator. Due to a mounting defect, the transverse axis (Z) can be inclined with respect to the upper surface (T1) of the first structural element by an angle comprised between 1 and 5.

[0066] The axial dissipator (8) comprises a bracket (80) composed of a U-bent plate intended to be deformed with axial stress along the transverse axis (Z), both in traction and in compression, to compensate for a movement produced by compressive actions, in which the structural elements (P, T) are moved closer, and for a movement produced by tractive actions, in which the structural elements (P, T) are moved apart.

[0067] The axial dissipator (8) is connected to the sliding element (4) by means of a first hinge (5) that permits a rotation around a vertical axis (Y) orthogonal to the longitudinal axis (X) and to the transverse axis (Z).

[0068] Moreover, the axial dissipator (8) is connected to the connector (C) by means of a second hinge (9) that permits a rotation around an axis (X1) parallel to the longitudinal axis (X).

[0069] With reference to FIG. 6, the bracket (80) of the axial dissipator (8) comprises a base (81) and two wings (82) that extend orthogonally from the base. The base (81) is faced towards the connector (C) and the wings (82) are faced towards the flexural dissipator (2). Moreover, the two wings (82) of the bracket (80) of the axial dissipator are disposed on planes above and below the longitudinal axis (X) of the flexural dissipator (2).

[0070] The transverse axis (Z) orthogonally passes by the center of the base (81) of the flexural dissipator.

[0071] A nut (83) is disposed inside the bracket (80). The nut has a threaded hole (86).The nut (83) is connected to the base (81) of the axial dissipator (8) by means of a wing (84), in such a way that the nut (83) is disposed with an axis that coincides with the axis (X1) of the second hinge (9).

[0072] Holes (85) with an axis that coincides with the vertical axis (Y) of the first hinge (5) are obtained in the two wings (82) of the axial dissipator. The vertical axis (Y) is orthogonal to the longitudinal axis (X) of the flexural dissipator and to the transverse axis (Z).

[0073] With reference to FIG. 4, for illustrative purposes, the flexural dissipator (2) can consist in a metal section, for example a steel section, and can have a shape with H-section or a tubular shape with rectangular section, being internally empty.

[0074] The flexural dissipator (2) is connected to the first structural element (T) by means of two flanges (3, 3) disposed at the ends of the flexural dissipator (2). The flanges (3, 3) are connected to the upper surface (T1) of the first structural element in order to raise the flexural dissipator (2) with respect to the first structural element (T), defining a space (G) between the upper surface (T1) of the first structural element and the flexural dissipator (2). The longitudinal axis (X) of the flexural dissipator (2) is parallel to the internal surface (P1) of the second structural element.

[0075] Each flange (3, 3) has an L-shaped transverse section and is provided with a first wing (30) connected to the first structural element (T) and a second wing (31) connected to the flexural dissipator (2).

[0076] The first wing (30) of the first flange (3) has a slot (32) that extends in parallel direction to the longitudinal axis (X) of the flexural dissipator. The first wing (30) of the second flange (3) has a slot (32) that extends along an orthogonal direction to the longitudinal axis (X) of the flexural dissipator.

[0077] Bolts or inserts (33) are passed through the slots (32, 32) of each flange and firmly engaged in the first structural element (T). In view of the above, the dissipator (2) can translate in a parallel orthogonal direction relative to its longitudinal axis (X).

[0078] It must be noted that the slots (32, 32) of the flanges (3, 3) are orthogonal .The slot (32) of the first flange (3) is parallel to the longitudinal axis (X) in order to mount the aseismic device astride two different beams. In such a case, the slot (32) must be on a smooth surface in order to avoid the stress produced on the insert (32) by temperature variations between the beams. Instead, the slot (32) of the second flange (3) is orthogonal to the longitudinal axis (X) in order to minimize any errors made during the mounting process.

[0079] To control said orthogonal translation, a small plate (34) is connected to the bolt (33) of the second flange. By tightening the bolt (33), the small plate (34) is stopped against the first wing (30) of the second flange, producing friction between the small plate (34) and the first wing (30). In order to increase the friction, the small plate (34) has a grooved or knurled lower surface that is engaged with a grooved or knurled upper surface (36) of the first wing of the second flange. Advantageously, the grooved surface (36) of the first wing of the second flange is provided with a plurality of ribs that protrude in upper position from the first wing of the second flange in parallel direction to the longitudinal axis (X) of the flexural dissipator. Such a grooved surface (36) of the second flange (3) is used to retain the aseismic device (1) firmly in the most correct position.

[0080] The second wing (31) of each flange has a circular hole (37) and a slot (38) that extends in a direction orthogonal to the longitudinal axis (X) of the flexural dissipator and to the slot (32) of the first wing of the second flange.

[0081] Two attachments (20) are disposed at the ends of the flexural dissipator (2). Each attachment (20) has a first hole (21) and a second hole (21) with axes parallel to the longitudinal axis (X) of the flexural dissipator. A first screw (22) is inserted in the circular hole (37) of the second wing of the flange and in the first hole (21) of the attachment. A second screw (22) is inserted in the circular hole (38) of the second wing of the flange and in the first hole (21) of the attachment.

[0082] In this way, the first screw (22) can act as pivoting axis and the second screw (22) can move in the slot (38) of the second wing of the flange. Consequently, the flexural dissipator (2) can rotate around an axis (X2) that passes by the first screw (22); otherwise said, it can rotate around an axis parallel to the longitudinal axis (X) of the flexural dissipator. The dimensions of the slot (38) of the second wing control the rotation of the flexural dissipator. Such a measure compensates for the torsional stress suffered by the flexural dissipator (2) during an earthquake. Because of the provision of two hinges with axis parallel to the longitudinal axis (X) of the flexural dissipator (2), the first and the second structural element (T, P) can translate vertically in case of sussultatory seismic actions.

[0083] Advantageously, the first screw (22) and the second screw (22) are equally spaced and disposed in opposite position relative to the longitudinal axis (X) of the flexural dissipator.

[0084] Bushings (24, 24) are mounted on the screws (22, 22) that are partially threaded to prevent the screws (22, 22) from being overtightened and reduce the friction of the screws relative to the flanges (3).

[0085] As shown in FIG. 5, the sliding element (4) comprises a sleeve (40) closed as a ring around the flexural dissipator (2). Preferably, the sleeve (40) has a tubular shape with rectangular section. In view of the above, the sliding element (4) can slide on the flexural dissipator (2) along the space (G) between the flexural dissipator (2) and the first structural element (T). The flanges (3) disposed at the ends of the flexural dissipator (2) act as travel stops for the sliding element (4).

[0086] The sleeve (40) of the sliding element is disposed between the two wings (82) of the bracket (80) of the axial dissipator and surrounds the flexural dissipator (2) completely. Therefore, in case of vertical sussultatory oscillations combined with horizontal undulatory oscillations, the sleeve (4) is deformed, but retains the flexural dissipator (2) without producing clearance, thus preventing a hammering effect between the first structural element (T) and the second structural element (P).

[0087] Advantageously, the sleeve (40) is obtained from four plates that are mutually connected: a lower plate (41), an upper plate (42), a front plate (43) and a back plate (44). Two Teflon inserts (40a, 40b) are disposed in the sleeve (40) and intended to rub against a longitudinal front edge (2a) and a longitudinal rear edge (2b) of the flexural dissipator, respectively. The Teflon inserts (40a, 40b) act as sliding bearing. Considering that the flexural dissipator (2) is made of steel and steel and Teflon have a very low friction coefficient (approximately 0.04), the sliding element (4) can slide freely on the flexural dissipator (2).

[0088] The front and the back plates (43, 44) have a grooved or knurled internal surface (45) that is coupled with a grooved or knurled surface (48) of the Teflon inserts (40a, 40b). The grooved surface (45) of the front plate and of the back plate is provided with a plurality of ribs that protrude from the front plate and from the back plate in parallel direction to the axis (Y). The grooved surfaces (45, 48) of the sliding element and of the Teflon inserts are used to prevent the Teflon inserts from sliding relative to the sliding element.

[0089] The upper plate and the lower plate (41, 42) are provided with holes (46) with axis that coincides with the vertical axis (Y) of the first hinge (5). In view of the above, the sliding element (4) is disposed between the wings (82) of the axial dissipator in such a manner that the holes (85) of the wings of the axial dissipator are aligned with the holes (46) of the sliding element. The holes (46) of the sliding element are threaded holes.

[0090] Screws (50) are inserted in the holes (85) of the wings of the axial dissipator and tightened into the threaded holes (46) of the sliding element in such a way to form the first hinge (5) that permits the rotation of the axial dissipator around the vertical axis (Y). The screws (50) that are tightened in the threaded holes (46) of the sliding element are partially threaded to prevent overtightening.

[0091] The connector (C) comprises guide means (M) fixed to the second structural element (P). The second hinge (9) is connected to the guide means (M) in such a way to permit a translation and centering of the second hinge (9) along an axis parallel to the vertical axis (Y).

[0092] With reference to FIG. 7, the guide means (M) comprise two guides (6) intended to be fixed to the second structural element (P). Each guide (6) is provided with anchoring clamps (61) intended to be anchored to the second structural element (P).

[0093] Each guide (6) comprises two guide tracks (60) disposed in parallel position in such a way to form a space (62). The guide (6) can be a traditional Halfen guide composed of a C-section, which is normally found on the market.

[0094] Two carriages (7) are disposed in the space (62) of each guide, being suitable for sliding vertically in the direction of an axis parallel to the vertical axis (Y). Friction means are provided to block a free sliding movement of the carriages (7) in the guides (6). Each carriage (7) comprises a plate wherein a bolt (70) is mounted, protruding from the guide. A bushing is mounted on the bolt (70) to minimize the sliding friction.

[0095] The second hinge (9) comprises two flanges (90) shaped as a plate and disposed in parallel position. Each flange (90) has a slot (91) that extends in vertical direction. Two perforated attachments (92) protrude from each flange (9), being engaged by the bolts (70) of the guides (6), in such a way to connect the flanges (90) to the guides (6).

[0096] The axial dissipator (8) is disposed between the two flanges (90) of the second hinge, in such a way that the threaded hole (86) of the nut of the axial dissipator is in register with the slots (91) of the two flanges (90) of the second hinge. Two screws (93) are inserted in the slots (91) of the flanges (90) and tightened inside the nut (83) of the axial dissipator. The screws (93) are partially threaded to prevent overtightening. In view of the above, the axial dissipator (8) can rotate around the axis (X1) of the screws (93) that coincides with the axis of the second hinge (9). Moreover, the screws (93) can translate in the slots (91) of the two flanges, letting the axial dissipator additionally slide along the vertical axis (Y) in case of overtightening the screws (70) with the head inserted in the space (62) of the guides. In any case, the entire second hinge (9) can translate relative to the guides (6) along an axis parallel to the vertical axis (Y).

[0097] The longitudinal axis (X) of the flexural dissipator (2), the vertical axis (Y) of the first hinge (5) and the transverse axis (Z) form a Cartesian or non-Cartesian set of three axes because the transverse axis (Z) can be inclined with respect to a horizontal plane composed of the upper surface (T1) of the first structural element due to a mounting defect.

[0098] It must be noted that the aseismic device (1) permits a free relative moment of the second structural element (P) with respect to the first structural element (T) only in the direction of the longitudinal axis (X) because the sliding element (4) can slide freely relative to the flexural dissipator (2) along the longitudinal axis (X) of the flexural dissipator, permitting oscillatory actions parallel to the longitudinal axis (X).

[0099] Instead, the aseismic device (1) dampens the oscillatory actions in the direction of the transverse axis (Z), controlling the relative movement of the second structural element (P) with respect to the first structural element (T), in the direction of the transverse axis (Z) because of the provision of the axial dissipator (8) and of the flexural dissipator (2).

[0100] Moreover, because of the clearance of the hinges around the axes (X1 and X2) parallel to the longitudinal axis (X), the aseismic device (1) permits movements along the vertical axis (Y) as a consequence of the sussultatory seismic actions.

[0101] Moreover, the aseismic device (1) does not permit a free relative movement of the second structural element (P) with respect to the first structural element (T), in the direction of the vertical axis (Y) because of the provision of the friction means that block a free sliding movement of the carriages (7) in the guides (6), which have the main purpose of centering the device, controlling the mounting errors in vertical direction.

[0102] Consequently, if the first structural element (T) suffers oscillations in the direction of the longitudinal axis (X) of the flexural dissipator during an earthquake, the flexural dissipator (2) joined to the first structural element (T) can slide relative to the sliding element (4) in the direction of the axis (X), regardless of the second structural element (P), thus preventing any impulsive stress on the second structural element (P) and possible failures.

[0103] Moreover, if the first structural element (T) suffers oscillations in the direction of the transverse axis (Z) during an earthquake, the axial dissipator (8) and the flexional dissipator (2) are deformed when the structural elements (P, T) are moved apart, being compressed and shortened when the structural elements (P, T) are moved closer. In view of the above, the axial dissipator (8) and the flexional dissipator (2) compensate for the oscillations of the first structural element (T) in the direction of the transverse axis (Z), preventing the first structural element (T) from violently hitting and damaging the second structural element (P). The movement of the first structural element (T) along the transverse axis (Z) is additionally compensated because of the provision of the plate (34) of the second flange (3) that can frictionally slide on the first wing (30) of the second flange (3).

[0104] Moreover, if the first structural element (T) suffers oscillations in the direction of the vertical axis (Y) during an earthquake, such a movement is mainly compensated because of the rotation of the flexural dissipator (2) around the axis (X2) and of the rotation of the axial dissipator (8) around the axis (X1).

[0105] In order to prevent the flexural dissipator (2) from suffering high torsional stress during the earthquake, the aseismic device (1) of the invention provides for hinging the flexural dissipator (2) to the flanges (3, 3) along an axis (X2) parallel to the longitudinal axis (X) of the flexural dissipator. Moreover, also the axial dissipator (8) is connected to the second hinge (9) in such a way to rotate around an axis (X2) parallel to the longitudinal axis (X) of the flexural dissipator.

[0106] The axial dissipator (8) suitable for being deformed both in traction and compression, and the presence of the first hinge (5) and of the second hinge (9) connected to the axial dissipator permit to control the compression of the Teflon inserts (40, 40a) that act as sliding bearings when the flexural dissipator (2) is mounted with its longitudinal axis (X) not parallel to the plane (P1) of the structural element (P) and consequently not aligned with the sliding axis of the sliding element (4).

[0107] As a matter of fact, when the longitudinal axis (X) of the flexural dissipator (2) is inclined with respect to the sliding axis of the sliding element (4), during the sliding movement of the sliding element (4) along the flexural dissipator (2), in some areas of the flexural dissipator (2) the structural elements (P, T) are mutually stopped and tend to compress the Teflon inserts (40a, 40b) with the risk of causing the failure of the Teflon inserts (40a, 40b) and consequently jamming the sliding element (4). In such a case, because of its deformation, the axial dissipator (8) and the hinges (5, 9) prevent the compression and the failure of the Teflon inserts (40, 40a).

[0108] FIGS. 8 and 9 show the case in which the second structural element (P) is lowered with respect to the first structural element (T). Consequently, the flexural dissipator (2) rotates around the axis (X2) of the screws (22) that are engaged in the flanges (3, 3), and the screws (22) are lowered in the slots (38) of the flanges (3, 3).

[0109] FIGS. 10 and 11 show the case in which the first structural element (T) is lowered with respect to the second structural element (P). Consequently, the flexural dissipator (2) rotates around the axis (X2) of the screws (22) and the screws (22) are raised in the slots (38) of the flanges (3, 3).

[0110] In the cases of FIGS. 8-11, the flexural dissipator (2) does not suffer a high torsional stress because of the provision of the second hinge (9) connected to the axial dissipator that permits a rotation of the axial dissipator relative to the connector (C) around the axis (X1) of the second hinge.

[0111] FIGS. 12-14 show the case in which the aseismic device (1) is mounted with a mounting defect, wherein the axis (X) of the flexural dissipator (2) is not parallel to the internal surface (P2) of the second structural element. Because of such an installation, the first structural element (T) and the second structural element (P) are moved closer and apart during the sliding movement of the sliding element (4) on the flexural dissipator (2).

[0112] As shown in FIG. 13, when the sliding element (4) slides towards the area where the distance between the flexural dissipator (2) and the second structural element (P) increases, the axial dissipator (8) is deformed, discharging the very high tractive stress that would compress the Teflon insert in most external position (40a).

[0113] As shown in FIG. 14, when the sliding element (4) slides towards the area where the distance between the flexural dissipator (2) and the second structural element (P) decreases, the axial dissipator (8) is deformed, discharging the compressive stress that would compress the Teflon insert in most internal position (40a). As shown in FIG. 14, the space (S) between the first structural element (T) and the second structural element (P) increases when the sliding element (4) slides along the flexural dissipator (2) towards the area where the distance between the flexural dissipator (2) and the second structural element (P) decreases.

[0114] During the sliding movement of the sliding element (4) on the flexural dissipator (2), it is very important that the axial dissipator (8) can rotate around the axis (Y) of the first hinge (5) otherwise the sliding element (4) gets jammed and its sliding movement on the flexural element is prevented.

[0115] As shown in the examples of FIGS. 12-14, the flexural dissipator (2) and the axial dissipator (8) are not only used to dampen the actions by which the two structural elements (T, P) are moved closer or apart, but are mainly used to control the forces produced when the sliding movement of the sliding element (4) is prevented by mounting defects of the flexural dissipator (2).

[0116] Numerous variations and modifications can be made to the present embodiment of the invention, which are within the reach of an expert of the field, falling in any case within the scope of the invention.